Language：Japanese   Publisher：(公社)日本障害者歯科学会  

被虐待児童はう蝕が多いとされているが,これまでの報告の多くは,う蝕有病者率やう蝕経験歯数に限られていた.本研究では,被虐待児童におけるう蝕罹患状況の特徴を探索するため,歯種別に解析を行った.歯種別解析の対象は,2～19歳の一時保護所への入所理由が「虐待」の児童(虐待群)323名とした.年齢に応じて,乳歯の解析では2区分(2～5歳,6～9歳),永久歯では3区分(5～9歳,10～14歳,15～19歳)とし,歯科疾患実態調査(対照群)と比較を行った.乳歯,永久歯ともに一人平均未処置歯数は虐待群において有意に高く,永久歯においては一人平均う歯数がすべての年齢区分で虐待群が有意に高かった.歯種別に解析した結果,乳歯では上顎左側乳中切歯と上顎右側乳犬歯,永久歯では第一大臼歯と第二大臼歯において,虐待群が有意にう歯保有者率が高かったが,虐待群の歯種別う蝕罹患状況として明確な特徴と判断できるものはなく,一般にう蝕が発生しやすい部位において虐待群ではさらに高い割合でう蝕を有し,永久歯萠出直後早い段階で罹患していると考えられた.一人平均う歯数のパーセンタイル値では,いずれの年齢区分においても虐待群の25%は対照群と同様にう歯を有していなかった一方で,虐待群の一部の者のう歯数が非常に多く,虐待群の全体的なう蝕歯数の数値を引き上げていると推察された.(著者抄録)

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Other Link： https://search.jamas.or.jp/default/link?pub_year=2023&ichushi_jid=J02489&link_issn=&doc_id=20230403180002&doc_link_id=10.14958%2Fjjsdh.44.10&url=https%3A%2F%2Fdoi.org%2F10.14958%2Fjjsdh.44.10&type=J-STAGE&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00007_3.gif

Language：Japanese   Publisher：(公社)日本小児歯科学会  

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Language：Japanese   Publisher：(公社)日本小児歯科学会  

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Language：Japanese   Publisher：(公社)日本小児歯科学会  

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Language：Japanese   Publisher：新潟歯学会  

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Language：Japanese   Publisher：新潟歯学会  

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Language：Japanese   Publisher：新潟歯学会  

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Language：Japanese   Publisher：(公社)日本障害者歯科学会  

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Language：Japanese   Publisher：(公社)日本障害者歯科学会  

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Language：Japanese   Publisher：新潟歯学会  

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Language：Japanese   Publisher：新潟歯学会  

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Language：Japanese   Publisher：(公社)日本小児歯科学会  

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Language：Japanese   Publisher：(公社)日本小児歯科学会  

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Language：Japanese   Publisher：(公社)日本小児歯科学会  

わが国における舌小帯異常の発生頻度は、報告によって大きな開きがある。そこで、発現頻度、年齢間の比較、形態的異常と機能的問題との相関について検討することを目的として、全国的に4〜6歳の小児2,886名を対象として実態調査を行い、以下の結果を得た。1. 舌小帯は、長さが1cm未満および舌尖部の形態がハート型になる小児の割合が約10%であり、2mm以上肥厚している割合は約3%、中程度(1〜2mm)は約25%であった。また、年齢間で差は認められなかった。2. 舌の前方、側方および垂直運動で問題が認められた小児は、形態的な異常と同程度で、ポッピングや構音の不明瞭者は約30%であった。また、機能的項目については、年齢間で相関が認められ、年齢が増すごとに舌の可動域が大きくなり、指示通りに動かすことができた。3. 舌小帯の形態と機能との間には相関が認められ、長さや舌尖の形態は前方、側方および垂直運動での機能的な問題と関連が強かった。4. 下顎の正中離開や咬合関係は、舌小帯の形態的および機能的な問題との関連性は非常に弱かった。(著者抄録)

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY  

BACKGROUND/AIM: Root length is a critical factor for dental pulp regeneration following tooth replantation. The aim of this study was to analyze the effects of reducing the root length by apicoectomy on the pulp healing process using a model for tooth replantation. MATERIAL AND METHODS: After extraction of the upper first molars (M1) of 3-week-old mice, the roots from the experimental group (EG) were shortened to half to two-thirds of their length before replantation, whereas in the control group (CG) the extracted teeth were immediately repositioned into their alveolar sockets. To determine the effects of root resection on the survival of inherent pulp cells, this study included tooth transplantation with root resection using wild-type (WT) and green fluorescent protein (GFP) transgenic mice. The M1 of GFP transgenic mice were transplanted into the alveolar socket of the M1 of WT mice. The roots of the right M1 were shortened (EG), whereas the left M1 remained untreated (CG). RESULTS: Apoptotic cells in the EG significantly decreased in number compared with the CG at day 3. Cell proliferative activity in the EG was significantly higher than that in the CG in the root pulp during days 3-5, and nestin-positive odontoblast-like cells began to arrange themselves along the pulp-dentin border in the cusp area at day 5 in the EG but not in the CG. At week 2, tertiary dentin had formed throughout the pulp in the EG, whereas the combined tissue of dentin and bone occupied the pulp space in 60% of the CG. Root resection also positively affected the survival of inherent pulp cells to differentiate into odontoblast-like cells as demonstrated by transplantation using GFP transgenic mice. CONCLUSIONS: Reducing the root length accelerated pulp regeneration following tooth replantation due to the better environment for revascularization.

DOI： 10.1111/edt.12679

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Alpha-thalassemia X-linked intellectual disability (ATR-X) syndrome affects males and is associated with profound developmental delay, facial dysmorphism, genital abnormalities, and alpha thalassemia. Appropriate oral health management for affected patients is important. The purposes of this report are to describe a case involving six years of oral health management, including training in eating, drinking and swallowing, for a patient with ATR-X syndrome, and to discuss the morphological and functional oral characteristics of this disorder. The patient's oral dysfunctions were incompetent lip-closing, inappropriate tongue protrusion, deviation of chewing acquisition, and incompetent oral and pharyngeal bolus propulsion. Other problems included inappropriate ingestion posture, low interest in meals, and poor oral hygiene. A stable oral intake and an improved eating posture were achieved through an intervention; however, the patient's inappropriate tongue protrusion, deviation of chewing acquisition, and incompetent bolus propulsion remained unchanged.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY  

OBJECTIVES: Weakening of lip-closing strength (LCS) associated with an incompetent lip seal (ILS) may affect the oral balance between the lip and tongue pressures. The purpose of this study was to evaluate the effects of lip-closing training in children with lower LCS and/or abnormal habits across different age groups and to compare its effects on increasing LCS in children with malocclusion and/or oral habits. MATERIAL AND METHODS: Lip-closing training was performed by 154 Japanese children aged 3-12 years using a specialized training device at home for 3 months. Children with oral habits and/or exhibiting less than standard LCS were included. LCS was measured using a digital strain force gauge at a dental clinic at the beginning (T0) and after each month (after 3 months: T3). RESULTS: Children had higher LCS responses after lip-closing training. The first month of lip-closing training was more effective than the subsequent months. With lip-closing training, the LCS increased from an average of 6.2 N (T0) to 11.4 N (T3) in Group I, 7.9 N (T0) to 12.8 N (T3) in Group II, and 6.8 N to 11.4 N in Group III. Anterior cross bite, including reverse bite, open bite, and tongue thrusting, significantly reduced training effects. CONCLUSION: Our findings showed that lower LCS in children with ILS resulted in greater responses to lip-closing training in a short period, but oral dysfunction, such as abnormal habits, inhibited the positive effects of training. Our results suggest that less detrimental effects of malocclusion and abnormal oral habits lip-closing training enhances LCS in younger children.

DOI： 10.1002/cre2.490

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY  

BACKGROUND: Understanding the refinement of self-feeding skills is useful for the assessment of oral functional development in children. OBJECTIVES: To determine normative data on lip closing during food intake in the development of independent spoon-feeding in normal children, we tested the hypothesis that lip-closing pressure and spoon operation differ depending on food type. METHODS: Fifteen normal children (eight boys, seven girls; mean age: 6.5 years) were asked to eat test foods (2, 3 and 5 g of yogurt and cream cheese) freely with a spoon. Lip-closing pressures and kinematic data on spoon operation were recorded simultaneously with a strain gauge transducer embedded in the spoon and Vicon motion analysis, respectively. RESULTS: In the most common lip-pressure pattern, only positive pressure was generated. In the second most common pattern, negative pressure occurred first, followed by positive pressure; this pattern was seen infrequently. Positive pressure (P < .001), pressure duration (P < .001) and spoon intra-oral time (P < .05) during intake of cream cheese (an adhesive food) were significantly greater than those during intake of yogurt (a non-adhesive food). Pressure onset occurred at the beginning of the spoon withdrawal period or at the turning point from spoon insertion to withdrawal, depending on the food. CONCLUSIONS: Lip-closing force and spoon operation varied depending on food type in preschool and early elementary school children. Our findings suggest the need to consider the importance of food diversity and to pay attention to the spoon withdrawal period when assessing the development and maturation of lip function.

DOI： 10.1111/joor.13155

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

BACKGROUND: Systemic and local factors may lead to disruption of craniofacial growth and development, causing an imbalance between the orofacial skeleton, muscle and soft tissue, dental occlusion, and the dental arch during growth periods. We aimed to reveal whether the prevalence of incompetent lip seal (ILS) varies with age and region, as well as to clarify the factors related to an ILS, in a national, large-scale epidemiological study. METHODS: We surveyed 3399 children, from 3 to 12 years of age, visiting 66 pediatric dental clinics throughout Japan. For this survey, we employed a questionnaire consisting of 44 questions regarding daily health conditions and lifestyle habits. We evaluated the differences in ILS prevalence by age and region (using a Cochran-Armitage test for trend and a Kruskal-Wallis test), and the relationship between ILS and factors investigated in the questionnaire (using Spearman's rank correlation coefficient). RESULTS: We observed that 30.7% of Japanese children exhibited an ILS and that the ILS rate increased with age (p < 0.001). There were no regional differences in the rate of ILS in Japanese children (p = 0.506). We revealed that 12 of 44 survey items exhibited a statistically significant correlation with ILS (p < 0.001), using Spearman's rank correlation coefficient. These items involved orofacial morphology, mouth breathing, and possibly, allergic rhinitis. CONCLUSION: The rate of ILS seems to increase with age in children, throughout Japan. Therefore, this disorder may not self-correct during the growth periods in these children. Guidelines are required for pediatric dentists to recognize ILS among children aged 3-12 years.

DOI： 10.1186/s12199-021-00933-5

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Language：Japanese   Publisher：新潟歯学会  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MDPI  

Pluripotent stem cells are classified as naïve and primed cells, based on their in vitro growth characteristics and potential to differentiate into various types of cells. Human-induced pluripotent stem cells (iPSCs, also known as epiblast stem cells [EpiSCs]) have limited capacity to differentiate and are slightly more differentiated than naïve stem cells (NSCs). Although there are several in vitro protocols that allow iPSCs to differentiate into pancreatic lineage, data concerning generation of β-cells from these iPSCs are limited. Based on the pluripotentiality of NSCs, it was hypothesized that NSCs can differentiate into pancreatic β-cells when placed under an appropriate differentiation induction condition. We examined whether NSCs can be efficiently induced to form potentially pancreatic β cells after being subjected to an in vitro protocol. Several colonies resembling in vitro-produced β-cell foci, with β-cell-specific marker expression, were observed when NSC-derived embryoid bodies (EBs) were induced to differentiate into β-cell lineage. Conversely, EpiSC-derived EBs failed to form such foci in vitro. Intrapancreatic grafting of the in vitro-formed β-cell foci into nude mice (BALB/c-nu/nu) generated a cell mass containing insulin-producing cells (IPCs), without noticeable tumorigenesis. These NSCs can be used as a promising resource for curing type 1 diabetes.

DOI： 10.3390/jcm9092838

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS LTD  

The present study aimed to develop a more biomimetic tissue-engineered oral mucosa equivalent comprising 1% type I tilapia scale collagen scaffold having microstructures mimicking the dermal-epidermal junction of oral mucosa and oral keratinocytes as graft materials for human use. We designed four micropattern prototypes mimicking the dermal-epidermal junction. Using a semiconductor process and soft lithography, negative molds were fabricated to develop microstructures using both polydimethylsiloxane and silicon substrates. Micropattern configurations of dermal-epidermal junctions manufactured from fish collagen consisting of a fibril network using our micropatterning system were well preserved, although the internal fibril network of the pillar pattern was sparse. Mixing 1% chondroitin sulfate with the collagen matrix minimized tissue-engineered oral mucosa equivalent contraction. Histologic examinations showed a flattening of the vertical dimensions of all microstructures and expansion of their pitches, indicating changes in the originally designed configurations. Nonetheless, histologic examinations revealed that a fully differentiated and stratified epithelial layer was developed on all scaffolds, suggesting that the microstructured fish scale collagen scaffolds have potential in the manufacturing of tissue-engineered oral mucosa equivalents for clinical use; however, enhancement of the mechanical properties of micropatterns is required. Our micropatterning technology can also apply to the development of oral mucosa in vitro models.

DOI： 10.1080/09205063.2019.1706147

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Lip closing is an important motor act in food acquisition. Appropriate food capture in anticipatory and early oral stages of feeding is essential for mastication and swallowing. The aim of this study was to investigate the effect of food type and quantity on lip closing pressure during food capture with a spoon, and to identify normal lip function during food acquisition in healthy young adults. Twenty young healthy males (age range: 22-30 years) participated in this study. They were asked to eat the test food freely with a spoon. Test foods were yogurt and cream cheese, which were given in quantities of 3, 5 and 10 g in weight; 3 ml water was included as a reference. A strain gauge transducer was embedded in the spoon in advance, and lip closing pressures during food capture were measured and recorded. The Vicon motion analysis system was used to collect three-dimensional kinematic data of spoon operation. Positive pressure with lip closing during capture of adhesive food, such as cream cheese, significantly increased (P < 0.001). Moreover, positive pressure significantly decreased when food quantity increased (P < 0.01), irrespective of food type. Negative pressure that preceded positive pressure appeared more frequently during cream cheese intake and increased when food quantity on the spoon increased (P < 0.001). These findings indicated that participants sucked or squeezed the spoon further during capture of adhesive food. Maximum mouth opening occurred predominantly during the spoon insertion period, while mouth closing occurred predominantly during the spoon withdrawal period. After mouth closing, all subsequent lip pressure events appeared in the withdrawal period. Our results may be useful for comprehending normal lip function during food acquisition in healthy young adults. They may also aid in the diagnosis and management of abnormal lip function in oral hypofunction and dysfunction, which can be examined in future studies.

DOI： 10.1016/j.physbeh.2019.112743

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER  

Objective: Investigation of dynamic occlusal contacts when food particles are being pulverized during chewing is of interest for many researchers and clinicians. However, measurement of dynamic occlusal contacts during chewing is difficult, and differences between children and adults have not been established. The purpose of this study is to test the hypothesis that dynamic occlusal contacts of children differ from those of adult females.Subjects: and methods: Thirteen healthy children (4-6 years of age; mean age 5 years, 7 months) and thirteen adult females (18-26 years of age; mean age 20 years, 7 months) with normal occlusion participated in this study. Occlusal contact area (OCA) was estimated with a developed measurement system combining 3-D digitization of tooth shape with 3-D tracking of mandibular movements (1) during the closing stroke, (2) at the maximum closing position (MCP), and (3) during the opening stroke. OCA at static maximum intercuspation (ICP) was also estimated.Results: At the MCP, the children's OCA was less than 76.4% of the contact area seen at the ICP. The timing of maximum OCA in children was shifted more towards the opening stroke compared with adults, and the OCA remained greater during opening in children than adults. The occurrence of the MCP was less stable in children than in adults, both between subjects and within subjects.Conclusions: We conclude that both the amount of OCA and the pattern of occlusal contacts during the occlusal phase of chewing completely differ between children and adult females. (C) 2019 Japanese Society of Pediatric Dentistry. Published by Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.pdj.2019.07.004

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Language：Japanese   Publisher：日本歯科衛生学会  

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J-GLOBAL

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

Human tissue-specific stem cells (hTSCs), found throughout the body, can differentiate into several lineages under appropriate conditions in vitro and in vivo. By transfecting terminally differentiated cells with reprogramming factors, we previously produced induced TSCs from the pancreas and hepatocytes that exhibit additional properties than iPSCs, as exemplified by very low tumour formation after xenogenic transplantation. We hypothesised that hTSCs, being partially reprogrammed in a state just prior to iPSC transition, could be isolated from any terminally differentiated cell type through transient reprogramming factor overexpression. Cytochemical staining of human deciduous tooth-derived dental pulp cells (HDDPCs) and human skin-derived fibroblasts following transfection with Yamanaka's factors demonstrated increased ALP activity, a stem cell marker, three weeks after transfection albeit in a small percentage of clones. Repeated transfections (≤3) led to more efficient iPSC generation, with HDDPCs exhibiting greater multipotentiality at two weeks post-transfection than the parental intact HDDPCs. These results indicated the utility of iPSC technology to isolate TSCs from HDDPCs and fibroblasts. Generally, a step-wise loss of pluripotential phenotypes in ESCs/iPSCs occurs during their differentiation process. Our present findings suggest that the reverse phenomenon can also occur upon repeated introduction of reprogramming factors into differentiated cells such as HDDPCs and fibroblasts.

DOI： 10.1038/s41598-018-37291-2

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：(一社)日本衛生学会  

日本全国の7〜9歳児4496名を対象に、第一大臼歯と切歯に限局して発生するエナメル質形成不全(MIH)の有病率と全国8地域の差異を調査した。対象児の地域は妊娠時の母親の居住地とした。ロジスティック回帰分析を使用して、MIH有病率が年齢群、性別、地域間で異なるか否か評価した。その結果、日本全体のMIH有病率は19.8%であった。MIH有病率は、北海道地区が14.0%、東北地区が11.7%、関東信越地区が18.5%、東海北陸地区が19.3%、近畿地区が22.3%、中国地区が19.8%、四国地区が28.1%、九州地区が25.3%であり、この地域差は統計的に有意であった。また、MIH有病率は年齢とともに低下し、性別による差異は観察されなかった。以上から、MIHの有病率には地域差があり、北東部よりも南西部で頻度が高いことが判明した。

DOI： 10.1186/s12199-018-0748-6

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY  

Streptococcus pyogenes is a bacterium that causes systemic diseases such as pharyngitis and toxic shock syndrome. S. pyogenes produces molecules that inhibit the function of the human immune system, thus allowing growth and spread of the pathogen in tissues. It is known that S. pyogenes CAMP factor induces vacuolation in macrophages; however, the mechanism remains unclear. In the current study, the mechanism by which CAMP factor induces vacuolation in macrophages was investigated. CAMP factor was found to induce calcium ion uptake in murine macrophage RAW264.7 cells. In addition, EDTA inhibited calcium ion uptake and vacuolation in the cells. The L-type voltage-dependent calcium ion channel blockers nifedipine and verapamil reduced vacuolation. Furthermore, the phosphoinositide 3-kinase inhibitors LY294002 and wortmannin also inhibited the vacuolation induced by CAMP factor. Fluorescent microscopy revealed that clathrin localized to the vacuoles. These results suggest that the vacuolation is related to calcium ion uptake by RAW264.7 cells via L-type voltage-dependent calcium ion channels. Therefore, it was concluded that the vacuoles induced by S. pyogenes CAMP factor in macrophages are clathrin-dependent endosomes induced by activation of the phosphoinositide 3-kinase signaling pathway through calcium ion uptake.

DOI： 10.1111/1348-0421.12647

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier Ltd  

Objective: Mouth breathing syndrome (MBS) is defined as a set of signs and symptoms that may be completely or incompletely present in subjects who, for various reasons, replace the correct pattern of nasal breathing with an oral or mixed pattern. It is important to identify the relevant factors affecting MBS in order to diagnose its cause since breathing obstructions can result from multiple factors. The purpose of this study is to clarify the relevant factors and the interrelationships between factors affecting MBS among children. Design: We surveyed 380 elementary school children from 6 to 12 years in age. The questionnaire consisted of 44 questions regarding their daily health conditions and lifestyle habits and was completed by the children's guardians. A factor analysis was performed to classify closely related questions into their respective factors and to examine the strength of the correlation between the newly revealed factors. Results: Twenty-six out of the 44 questions were selected, and they were classified into seven factors. Factors 1–7 were defined as “Incompetent lip seal”, “Diseases of the nose and throat”, “Eating and drinking habits”, “Bad breath”, “Problems with swallowing and chewing”, “Condition of teeth and gums”, and “Dry lips”, respectively. There were also correlations between these factors themselves. Conclusion: MBS was categorized according to 7 major factors. Because Factor 1 was defined as “Incompetent lip seal”, which was representative of the physical appearance of mouth breathers and correlated with other factors, we suggested that MBS should consist of 7 factors in total.

DOI： 10.1016/j.archoralbio.2018.03.012

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY  

BackgroundOral inflammatory lesions assist in the diagnosis of certain systemic diseases that primarily affect other organs.MethodsA young girl, 3 years and 3 months old, presented with aphthous stomatitis, upper lip cheilitis, and swelling and bleeding of the upper gingiva. She had a medical history of repeated fever, skin tag of the anus, and constipation. Thus, it was suspected that her disease is a systemic disease with digestive symptoms. From clinical manifestation and endoscopy findings containing aphthoid ulcers in the bowel, she was diagnosed with very early-onset Crohn's disease (CD). Immediately, mesalazine was started.ResultsAfter 1 month, the oral symptoms were dramatically improved, and her general condition stabilized.ConclusionsOral symptoms often precede the appearance of gastrointestinal lesions in young CD patients, and oral conditions worsen if the disease remains untreated. Thus, assessment of patients with intractable stomatitis from the viewpoint of CD may aid in rapid diagnosis and better prognosis.

DOI： 10.1002/cap.10013

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DOI： 10.15761/DOCR.1000258

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DOI： 10.15761/DOCR.1000255

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Streptococcus pyogenes is a bacterium that causes systemic diseases, such as pharyngitis and toxic shock syndrome, via oral- or nasal-cavity infection. S. pyogenes produces various molecules known to function with serum components that lead to bacterial adhesion and invasion in human tissues. In this study, we identified a novel S. pyogenes adhesin/invasin. Our results revealed that CAMP factor promoted streptococcal adhesion and invasion in pharyngeal epithelial Detroit562 cells without serum. Recombinant CAMP factor initially localized on the membranes of cells and then became internalized in the cytosol following S. pyogenes infection. Additionally, CAMP factor phosphorylated phosphoinositide 3-kinase and serine-threonine kinase in the cells. ELISA results demonstrate that CAMP factor affected the amount of phosphorylated phosphoinositide 3-kinase and serine-threonine kinase in Detroit562 cells. Furthermore, CAMP factor did not reverse the effect of phosphoinositide 3-kinase knockdown by small interfering RNA in reducing the level of adhesion and invasion of S. pyogenes isogenic cfa-deficient mutant. These results suggested that S. pyogenes CAMP factor activated the phosphoinositide 3-kinase/serine-threonine kinase signaling pathway, promoting S. pyogenes invasion of Detroit562 cells without serum. Our findings suggested that CAMP factor played an important role on adhesion and invasion in pharyngeal epithelial cells.

DOI： 10.1016/j.micinf.2017.09.007

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier Ltd  

Objective Detailed evidence of a relationship between maltreated children and dental caries is limited. The purpose of this study was to investigate the prevalence of dmft and DMFT, and the characteristics of dental treatment level of children at two child guidance centers (CGC). Subject and methods A total of 166 children (mean age: 11.6 y ± 2.8) staying at two CGCs were examine, and their results were compared with those of the Survey of Dental Disease (SDD) carried out by the Japanese Society for Oral Health. Results Mean numbers of dental caries were 5.70 at the CGCs and 2.25 in the SDD. “Completely treated” children were 21.7% of total participants in the SDD, but only 3.6% at the CGCs. In addition, 7.0% of participants were “untreated” in the SDD, but 41.0% at the CGCs. The percentage of children without dental caries was 18.7% at the CGCs and 45.7% in the SDD. These differences between the CGCs and in the SDD were statistically significant. Conclusions Our results indicate that, due to a lack of daily oral care, dental caries are significantly more prevalent in children at CGCs. CGCs may be good places to improve neglected children's dental caries and oral health care.

DOI： 10.1016/j.pdj.2017.08.003

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Management of the developing dentition and occlusion performs early and healthy oral optimization by diagnosing and treating their malocclusion and dysfunction in optimal period. We treated a posterior open-bite triggered by an impacted tooth with ankylosis. Her second primary molar was impacted with ankylosis of the buccal roots. She usually had her tongue thrust against her right posterior teeth. Timely and actively accelerated eruption of her second premolar was produced by extracting her second primary molar with fenestration. Her result shows the importance of improving oral habits and treating the submersion in the optimal period during early growth.

DOI： 10.1016/j.pdj.2017.04.001

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：(公社)日本小児歯科学会  

口唇閉鎖力の強さ(LCS)の年齢に関連して変化するパターンや、その他の関連因子を調査する横断研究を施行した。日本人の小児554名(女児275名、年齢3〜12歳)を調査対象とした。口唇閉鎖力測定器の「りっぷるくん」を用いてLCSを測定し、被験児の親に対して質問紙調査を行った。検討の結果、LCSは3〜6歳にかけて年齢と共に増大したが7〜12歳では平坦相に達し、そのパターンはScammonの発育曲線における一般型に類似していた。3〜6歳児の集団では、調査項目のうち「年齢」とLCSとの間の相関係数は他の項目に比べて高かった。7〜12歳児では「性別」や「食事中に飲み物を飲むこと」がLCSと中等度に相関していた。小児のLCSに関しては、発達期(3〜6歳)と安定期(7〜12歳)の2つの時期が区別されることが示された。

DOI： 10.1016/j.pdj.2017.06.002

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DOI： 10.15761/DOCR.1000242

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DOI： 10.15761/DOCR.1000237

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Objective: Lymphoid enhancer-binding factor-1 (LEF1) is a 48-kD nuclear protein that is expressed in pre-B and T cells. LEF1 is also an important member of the Wnt/beta-catenin signaling pathway that plays important roles in the self-renewal and differentiation of embryonic stem cells. We speculated that LEF1 might function in the stem cells from human exfoliated deciduous teeth (SHED). In this study, we attempted to isolate such LEF1-positive cells from human deciduous dental pulp cells (HDDPCs) by genetic engineering technology, using the human LEF1 promoter.
Design: A piggyBac transposon plasmid (pTA-LEN) was introduced into HDDPCs, using the Neon (R) transfection system. After G418 selection, the emerging colonies were assessed for EGFP-derived fluorescence by fluorescence microscopy. Reverse transcription polymerase chain reaction (RT-PCR) analysis was performed using RNA isolated from these colonies to examine stem cell-specific transcript expression. Osteoblastic or neuronal differentiation was induced by cultivating the LEF1-positive cells with differentiation-inducing medium.
Results: RT-PCR analysis confirmed the expression of several stem cell markers, including OCT3/4, SOX2, REX1, and NANOG, in LEF1-positive HDDPCs, which could be differentiated into osteoblasts and neuronal cells.
Conclusions: The isolated LEF1-positive HDDPCs exhibited the properties of stem cells, suggesting that LEF1 might serve as a marker for SHED.

DOI： 10.1016/j.archoralbio.2017.04.033

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier Ltd  

Objective International association dental traumatology has published guideline for the primary dentition. The guideline indicates that, when the crown is dislocated in a labial direction, extraction of the affected tooth is the only choice of treatment for lateral luxation cases with severe displacement. However, retaining primary teeth is important. Here we present a case of a tooth with lateral luxation and severe displacement. Case A three-year-old girl presented with complaint of severe mobility of the left lower primary canine caused by hitting a water tap 1 month earlier. Result We performed a root canal filling after pulpectomy and crown height reducing. After 37 weeks, radiographic examination showed dramatically alveolar bone regeneration and we were able to treat and maintain. Conclusion We conclude that conservative treatment of a traumatized tooth can be effective even in cases of lateral luxation and severe displacement.

DOI： 10.1016/j.pdj.2016.11.002

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DOI： 10.15761/DOCR.1000232

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PUBLIC LIBRARY SCIENCE  

Type 1 diabetes occurs due to the autoimmune destruction of pancreatic beta-cells in islets. Transplantation of islets is a promising option for the treatment of patients with type 1 diabetes that experience hypoglycemic unawareness despite maximal care, but the present shortage of donor islets hampers such transplantation. Transplantation of insulin-producing cells derived from the patients themselves would be one of the most promising approaches to cure type 1 diabetes. Previously, we demonstrated that insulin-producing cells could be produced by transfecting murine pancreatic cells with Yamanaka's reprogramming factors. Non-obese diabetic (NOD) mice are naturally occurring mutant mice defective in insulin production due to autoimmune ablation of pancreatic beta-cells. In this study, we showed that glucose-sensitive insulin-producing cells are successfully generated by transfecting primary pancreatic cells from NOD mice (aged 6 months old) with a plasmid harboring the cDNAs for Oct-3/4, Sox2, Klf4, and c-Myc. Transfection was repeated 4 times in a 2 day-interval. Sixty-five days after final transfection, cobblestone-like colonies appeared. They proliferated in vitro and expressed pluripotency-related genes as well as Pdx1, a transcription factor specific to tissue-specific stem cells for the beta-cell lineage. Transplantation of these cells into nude mice failed to produce teratoma unlike induced pluripotent stem cells (iPSCs). Induction of these cells to the pancreatic beta-cell lineage demonstrated their capability to produce insulin in response to glucose. These findings suggest that functional pancreatic beta-cells can be produced from patients with type 1 diabetes. We call these resultant cells as "induced tissue-specific stem cells from the pancreas" (iTS-P) that could be valuable sources of safe and effective materials for cell-based therapy in type 1 diabetes.

DOI： 10.1371/journal.pone.0163580

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Language：Japanese   Publisher：(一社)日本口腔衛生学会  

DOI： 10.5834/jdh.66.3_338

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Other Link： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2016&ichushi_jid=J00440&link_issn=&doc_id=20160524380005&doc_link_id=%2Fdk1dehea%2F2016%2F006603%2F005%2F0338-0343%26dl%3D0&url=https%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fdk1dehea%2F2016%2F006603%2F005%2F0338-0343%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

Language：English   Publisher：(公社)日本小児歯科学会  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Streptococcus pyogenes produces molecules that inhibit the function of human immune system, thus allowing the pathogen to grow and spread in tissues. It is known that S. pyogenes CAMP factor increases erythrocytosis induced by Staphylococcus aureus beta-hemolysin. However, the effects of CAMP factor for immune cells are unclear. In this study, we investigated the effects of CAMP factor to macrophages. Western blotting analysis demonstrated that all examined strains expressed CAMP factor protein. In the presence of calcium or magnesium ion, CAMP factor was significantly released in the supernatant. In addition, both culture supernatant from S. pyogenes strain SSI-9 and recombinant CAMP factor dose-dependently induced vacuolation in RAW 264.7 cells, but the culture supernatant from Delta cfa isogenic mutant strain did not. CAMP factor formed oligomers in RAW 264.7 cells in a time-dependent manner. CAMP factor suppressed cell proliferation via G2 phase cell cycle arrest without inducing cell death. Furthermore, CAMP factor reduced the uptake of S. pyogenes and phagocytic activity indicator by RAW 264.7 cells. These results suggest that CAMP factor works as a macrophage dysfunction factor. Therefore, we conclude that CAMP factor allows S. pyogenes to escape the host immune system, and contribute to the spread of streptococcal infection. (C) 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

DOI： 10.1016/j.micinf.2015.10.003

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SAGE PUBLICATIONS INC  

Feeder cells are generally required to maintain embryonic stem cells (ESCs)/induced pluripotent stem cells (iPSCs). Mouse embryonic fibroblasts (MEFs) isolated from fetuses and STO mouse stromal cell line are the most widely used feeder cells. The aim of this study was to determine which cells are suitable for establishing iPSCs from human deciduous tooth dental pulp cells (HDDPCs). Primary cultures of HDDPCs were cotransfected with three plasmids containing human OCT3/4, SOX2/KLF4, or LMYC/LIN28 and pmaxGFP by using a novel electroporation method, and then cultured in an ESC qualified medium for 15 days. Emerging colonies were reseeded onto mitomycin C-treated MEFs or STO cells. The colonies were serially passaged for up to 26 passages. During this period, colony morphology was assessed to determine whether cells exhibited ESC-like morphology and alkaline phosphatase activity to evaluate the state of cellular reprogramming. HDDPCs maintained on MEFs were successfully reprogrammed into iPSCs, whereas those maintained on STO cells were not. Once established, the iPSCs were maintained on STO cells without loss of pluripotency. Our results indicate that MEFs are better feeder cells than STO cells for establishing iPSCs. Feeder choice is a key factor enabling efficient generation of iPSCs.

DOI： 10.3727/215517915X689038

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER HEIDELBERG  

The aim of this study was to demonstrate the effectiveness of an analysis of tooth brushing cycles using a system that measures tooth brushing motion and brushing force with an accelerometer and strain tension gage attached to a toothbrush.
Mechanical plaque removal with a manual toothbrush remains the primary method of maintaining good oral hygiene for the majority of the population. Because toothbrush motion has not been fully understood, it should be clarified by analysis of tooth brushing cycles.
Twenty healthy female dental hygienists participated in this study. Their tooth brushing motions were measured and analyzed using an American Dental Association-approved manual toothbrush to which a three-dimensional (3-D) accelerometer and strain tension gage were attached. 3-D motion and brushing force on the labial surface of the mandibular right central incisor and the lingual surface of the mandibular left first molar were measured, analyzed, and compared. Multilevel linear model analysis was applied to estimate variables and compare motion and forces related to the two tooth surfaces.
The analysis of tooth brushing cycles was feasible, and significant differences were detected for durations and 3-D ranges of toothbrush motion as well as brushing force between the two tooth surfaces.
The analysis used in this study demonstrated an ability to detect characteristics of tooth brushing motion, showing tooth brushing motion to change depending on the brushed location. These results also suggest that more detailed instructions might be required according to patient's oral condition.

DOI： 10.1007/s00784-013-1172-3

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS LTD  

The purpose of this study was to investigate the relationship between cephalometric nasal soft tissue and skeletal landmarks in adults. Lateral cephalograms from Japanese adults (30 men: mean age, 24.5 +/- 4.9years; 30 women: mean age, 20.3 +/- 3.3years; overall mean age, 22.4 +/- 2.4years) were used in this study. Twenty-two skeletal points and three soft tissue nasal points were marked on each subject's lateral cephalogram, and the coordinates of all the points were systematically digitised and transformed to a standardised plane. A forward stepwise regression analysis determined how combinations of the skeletal landmarks predict the location of the nasal soft tissue landmarks. Based on the result of our research, the location of the nasal soft tissue cephalometric landmarks in our adult subjects may be predicted based on skeletal landmarks, and different skeletal landmarks predicted the position of each soft tissue landmark in the adult males and females in this study.

DOI： 10.1080/00450618.2013.877079

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DOI： 10.1016/j.jdsr.2014.04.001

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STO feeder cells, a line established from mouse SIM embryonic fibroblasts, have been frequently used for establishing embryonic stem cells and maintaining them in an undifferentiated state. There are some reports demonstrating that fibroblastic cells have the ability to phagocytose Gram-positive bacterium (e.g., streptococci and staphylococci). In this study, we examined the possibility that STO cells could phagocytose Streptococcus mutans (a bacteria causing tooth decay), which always contaminates cultures of primarily isolated human deciduous dental pulp cells (HDDPCs). Simple cultivation of the primary HDDPCs in the absence of STO cells allowed S. mutans to massively propagate in the medium, thus leading to an opaque medium. In contrast, there was no bacterial contamination in the cultures containing mitomycin C (MMC)-inactivated STO cells. Furthermore, STO cells indicated bacterial phagocytic activity under fluorescent microscopy with the dye pHrodo. Besides removal of contaminating bacteria, STO feeder cells allowed the HDDPCs to spread out. These data suggest that MMC-treated STO cells can be useful for propagation of HDDPCs by eliminating contaminating bacteria and by promoting cellular outgrowth.

DOI： 10.3727/215517913X674234

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHROMA INC  

The purpose of this study was to test the null hypothesis that molar movement during gum chewing in children with primary dentition is as smooth as in adults. Twenty-two healthy children with primary dentition and 23 healthy adult females participated in this study. Mandibular movement during gum chewing was recorded using an optoelectronic analysis system with six degrees-of-freedom at 100 Hz, and 10 cycles were selected for analysis. Normalized jerk cost (NJC) at the incisors and working and balancing molars were calculated in each phase (i.e., opening, closing and occlusal level phases) for each chewing cycle. The NJC of the working side molar in children was larger than in adults in both the opening and occlusal phases. Inter-individual variances of the NJC in each phase in children and adults were smaller than corresponding intra-individual variances, except for the NJC during the occlusal phase of adults for the working and balancing side molars. The inter- and intra-individual variances of the NJC during the closing phase were the smallest in each phase for both children and adults. This indicates that the jaw movements of children with primary dentition are more variable, less smooth, and faster than that of adults.

DOI： 10.1179/crn.2013.31.4.003

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MOSBY-ELSEVIER  

Introduction: Rapid maxillary expansion (RME) is known to improve nasal airway ventilation. Recent evidence suggests that RME is an effective treatment for obstructive sleep apnea in children with maxillary constriction. However, the effect of RME on tongue posture and pharyngeal airway volume in children with nasal airway obstruction is not clear. In this study, we evaluated these effects using cone-beam computed tomography. Methods: Twenty-eight treatment subjects (mean age 9.96 +/- 1.21 years) who required RME treatment had cone-beam computed tomography images taken before and after RME. Twenty control subjects (mean age 9.68 +/- 1.02 years) received regular orthodontic treatment. Nasal airway ventilation was analyzed by using computational fluid dynamics, and intraoral airway (the low tongue space between tongue and palate) and pharyngeal airway volumes were measured. Results: Intraoral airway volume decreased significantly in the RME group from 1212.9 +/- 1370.9 mm(3) before RME to w279.7 +/- 472.0 mm(3) after RME. Nasal airway ventilation was significantly correlated with intraoral airway volume. The increase of pharyngeal airway volume in the control group (1226.3 +/- 1782.5 mm(3)) was only 41% that of the RME group (3015.4 +/- 1297.6 mm(3)). Conclusions: In children with nasal obstruction, RME not only reduces nasal obstruction but also raises tongue posture and enlarges the pharyngeal airway. (Am J Orthod Dentofacial Orthop 2013;143:235-45)

DOI： 10.1016/j.ajodo.2012.09.014

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Head rotation is coordinated with mandibular movement during mouth opening, and the range of head rotation and mouth opening change with food size. However, past research did not include upper body movement, and no reports have related head and mandibular movement during realistic eating. The purpose of this study was to analyse head and mandibular movements with intake of different-sized food pieces during realistic eating. The test food consisted of apple cut into two different cube sizes (10 mm and 20 mm). Head and mandibular movements of 20 healthy young adults eating the apple pieces were simultaneously recorded in three dimensions by a wireless opto-electronic system. Reflective markers were attached to the upper lip and chin to measure the mouth opening range. Five markers were attached to eyeglasses frames to measure linear motion and rotation of the head. One marker was attached to the jugular notch of the sternum to measure linear motion of the upper body. Linear motion, and the inclination angle of the head and upper body, and mouth opening range were compared during intake of different-sized apple pieces. Mouth opening, head-neck rotation angle and the amount of upper body forward translation and inclination increased with larger apple pieces. However, isolated relative head motion was stabilized. We conclude that upper body forward motion and head-neck rotation assist mouth opening whilst stabilizing head orientation, and that the range of head-neck rotation angle, upper body translation and range of mouth opening change with food size during realistic eating. © 2011 Elsevier Ltd.

DOI： 10.1016/j.archoralbio.2011.08.023

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MOSBY-ELSEVIER  

Introduction: Rapid maxillary expansion is known to improve nasal airway ventilation. However, it is difficult to precisely evaluate this improvement with conventional methods. The purpose of this longitudinal study was to use computational fluid dynamics to estimate the effect of rapid maxillary expansion. Methods: Twenty-three subjects (9 boys, 14 girls; mean ages, 9.74 +/- 1.29 years before rapid maxillary expansion and 10.87 +/- 1.18 years after rapid maxillary expansion) who required rapid maxillary expansion as part of their orthodontic treatment had cone-beam computed tomography images taken before and after rapid maxillary expansion. The computed tomography data were used to reconstruct the 3-dimensional shape of the nasal cavity. Two measures of nasal airflow function (pressure and velocity) were simulated by using computational fluid dynamics. Results: The pressure after rapid maxillary expansion (80.55 Pa) was significantly lower than before rapid maxillary expansion (147.70 Pa), and the velocity after rapid maxillary expansion (9.63 m/sec) was slower than before rapid maxillary expansion (13.46 m/sec). Conclusions: Improvement of nasal airway ventilation by rapid maxillary expansion was detected by computational fluid dynamics. (Am J Orthod Dentofacial Orthop 2012; 141:269-78)

DOI： 10.1016/j.ajodo.2011.08.025

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHROMA INC  

The purpose of this study was to clarify the characteristics of permanent and primary tooth-crown inclinations. Landmark points from cephalograms and dental casts of two groups; 23 women (mean 20.3 +/- 3.3 years) and 11 girls (mean 5.2 +/- 0.1 years) were digitized, ad the coordinates were integrated and transformed to a standardized plane. The 3-dimensional crown inclinations were projected on the sagittal plane, and the angles between the tooth vectors and the FH plane were calculated. An independent-group t-test was used to test for group differences of each tooth inclination, and correlation coefficients were generated for the inclination angles among the permanent and primary teeth. Most maxillary tooth-crown inclinations showed significant age-related differences, while only the second premolar and primary second molar differed significantly in the mandible. The maxillary molars were parallel to the corresponding mandibular molars and correlated with each other, but the primary molars were not. Significant correlations were found between inclinations of most permanent teeth, but not the primary teeth. Maxillary tooth-crown inclinations change during growth, but tooth-crown inclinations of the mandibular teeth do not.

DOI： 10.1179/crn.2012.006

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Objective: Occlusal contact area (OCA) is most important during the occlusal phase when food particles are being pulverized. OCA is most easily measured statically at the maximum intercuspal position (ICP). However, the assumption of coincidence between dynamic maximum closing position (MCP) and statically determined ICP has not been previously tested. The purpose of this study is to introduce a method of quantifying OCA of all teeth during dynamic mastication to determine whether the OCA at the dynamic MCP during chewing is similar to the statically determined maximum possible OCA.
Design: Thirteen healthy females participated in this study. Morphologic tooth shape data were measured from dental models using an automatic 3D digitizer. Mandibular movement during gum chewing was recorded using an optoelectronic analysis system with 6 degrees of freedom, and ten cycles were selected for analysis. The dynamic OCA was estimated with a measurement system combining 3D tracking of mandibular movements with 3D digitization of tooth shape.
Results: The estimated mean 3D difference between the incisor position at ICP and MCP was 0.129 mm. At the dynamic MCP, the maximum OCA was 98.5% (68.42 mm(2)) of the maximum possible contact area in the static ICP (69.46 mm(2)). Both between-subject and within-subject variation were least at the dynamic MCP.
Conclusion: The maximum OCA during chewing is nearly identical to statically determined maximum possible OCA. (C) 2011 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.archoralbio.2011.07.004

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MOSBY-ELSEVIER  

Introduction: The purpose of this study was to test the null hypothesis that dolichofacial and brachyfacial children with Class II malocclusion do not differ in upper airway obstruction. Furthermore, the ability of fluid-mechanical simulation to detect airway obstruction within the limitations of simulation was examined. Methods: Forty subjects from 7 to 11 years of age with Class II malocclusion participated and were divided into 2 groups, dolichofacial and brachyfacial, based on their Frankfort mandibular plane angles. Cone-beam computed tomography images supplied the shape of the entire airway. Two measures of respiratory function, air velocity and pressure, were simulated by using 3-dimensional images of the airway. The images and simulations were compared between the 2 facial types. Results: The size of the upper airway did not differ statistically between facial types; however, the simulated maximal pressure and velocity of the dolichofacial type were significantly higher than those of the brachyfacial type. Conclusions: Airway obstruction differs with the Frankfort mandibular plane angle, even though the depth and cross-sectional area of the airway do not. The fluid-mechanical simulation system developed in this study detected differences in airway obstruction that were not apparent from morphologic studies. (Am J Orthod Dentofacial Orthop 2011;139:e135-e145)

DOI： 10.1016/j.ajodo.2010.08.014

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：E H ANGLE EDUCATION RESEARCH FOUNDATION, INC  

Objective: To test the hypothesis that there is no difference in the pharyngeal airway width and the position of the maxillofacial skeleton between prognathic and normal children.
Materials and Methods: Twenty-five girls with prognathism (mean, 7.9 +/- 0.9 years old) and 15 girls with normal occlusion (mean, 8.4 +/- 1.5 years) participated in this study. On each girl's lateral cephalogram, the coordinates of all points were marked and systematically digitized using a mechanical three-dimensional digitizing system. An independent-groups t-test was used to detect significant upper and lower pharyngeal width differences between the two groups. Correlations between the horizontal positions of each point and upper and lower pharyngeal widths were examined.
Results: Prognathic girls had a significantly wider lower pharyngeal airway compared with those with normal occlusion (P = .01). Furthermore, the horizontal coordinate of Ar was significantly positively correlated with lower pharyngeal airway width in both groups of girls.
Conclusions: The hypothesis is rejected. The mandible in prognathic girls tends to be positioned more anteriorly, resulting in a wider lower pharyngeal airway. (Angle Orthod. 2011;81:75-80.)

DOI： 10.2319/013010-65.1

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Concomitant head and mandibular movement during jaw function is well known in adults; however, its importance in children has not been studied. The brain attains 85-90% of its adult weight at 5 years of age, though the maximum rate of condylar growth is attained at approximately 14 years of age. These findings suggest that the coordination of the head and mandible may differ between children and adults. This study investigated head and mandibular movements of 19 children with complete primary dentition (average age: 5 years 5 months) and compared their functional integration of jaw and head movements to those of 16 female adults (average age: 20 years 3 months) with permanent dentition. Although the mandibular opening distance was significantly greater in the adults, the magnitude of concomitant head motion was greater in children. The results suggest that head extension in children helps increase the magnitude of mouth opening more than in adult women. (C) 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.archoralbio.2010.08.014

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHROMA INC  

This cross-sectional study tested the reproducibility of a simple button-pulling system for measuring lip-closing strength in normal preschool children and compared their strength to that of normal adults. The sample consisted of 348 preschool children and 123 adults. Lip-closing strength was measured by inserting a button, fastened to a piece of string, into the vestibule between the incisors and lips with minimal mouth opening. The string was attached to a digital tension gauge and was pulled parallel to the floor. Maximum tension, with three repetitions, was recorded at the instant that the button was pulled out of the mouth. Multilevel statistical models were used to evaluate any differences in contractive muscle strength between age groups and between the genders. The strength in children increased significantly from three years to five years (p&lt;0.01). Gender-related differences were found in adults but not in preschool children. Inter-individual variation at each age was larger than intra-individual variation. Measurement of lip-closing strength by button pulling is highly reproducible in children and has potential clinical and research applications.

DOI： 10.1179/crn.2010.032

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The purpose of this study was to clarify whether the reverse cycle during chewing is abnormal in children with primary dentition. Children with normal primary dentition (N = 23; 5·5 ± 0·8 years) and female adults (N = 25; 20·7 ± 1·9 years) participated in this study. Chewing movement was recorded using an opto-electronic analysis system with six degrees-of-freedom (TRI-MET, Tokyo-shizaisha; Tokyo, Japan). Each subject was given a stick of chewing gum (new TRIDENT, WARNER-LAMBERT CO., Morris Plains, NJ, USA) and instructed to chew it normally. Starting from the maximum intercuspal position, each chewing sequence was recorded over a period of 20 s. A custom computer program identified individual chewing cycles. Frontal views were used to distinguish seven types of cycle shapes according to Ahlgren (Acta Odontol Scand, 24, 1966, 1-109; Acta Odontol Scand, 25, 1967, 3-13). Multilevel statistical models evaluated differences between children and adults. In the adults, type II cycles that initially opened towards the balancing side and then moved towards the working side were the most common, and the closing pathway was lateral to the opening pathway. In the children, type V (reverse) cycles that opened towards the working side were most common, the closing pathway was medial to the opening pathway, and there was a smaller lateral component during opening and closing than in adults (P &lt; 0·05). We conclude that the reverse cycle is not abnormal because normal children with primary dentition have a smaller lateral component and difficulty in controlling asymmetric muscle activity. © 2009 Blackwell Publishing Ltd.

DOI： 10.1111/j.1365-2842.2009.02006.x

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHROMA INC  

This study was undertaken to characterize jaw motion during mastication in children with primary dentition and to compare jaw motion with that in adults. The means and the variances of the traditional parameters for the chewing cycle, i.e., duration, excursive ranges and 3-D distances of travel at the lower incisor, molars and condyles were analyzed and compared in 23 children and 25 female adults. The duration of opening in children was significantly shorter than that of adults. Significant differences between children and adults were observed in lateral and vertical excursion of the incisor, lateral excursion at the molars, and vertical excursion at the condyles. Many of these measurements had larger between-subject and between-cycle variances in children than adults, suggesting that chewing motion in children has not yet matured. The results of this study indicate that chewing motion in children is different from that of adults.

DOI： 10.1179/crn.2010.004

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Anterior crossbite (ACB) malocclusions are frequent; however, its characteristic functional features have not been fully described. The purpose of this study was to determine the characteristics of habitual mandibular open-close motion in children with ACB of their primary dentition. Two groups of children were selected for study; 17 with ACB (eight boys and nine girls; four years one month to seven years one month) and 19 with normal occlusion (eight boys and 11 girls; four years six months to six years seven months). The motion was recorded using an optoelectronic analysis system with six degrees-of-freedom. Mandibular incisor and condylar motion were analyzed by measuring their three-dimensional ranges and trajectories. Also estimated incisor and condylar pathways of the two groups were compared. Patients with ACB opened wider with more anterior-posterior condylar translation and more mandibular rotation. Although between-subject (inter-individual) variance of all variables in children with ACB was larger, they had less within-subject variance at the condyles. These results indicate that open-close mandibular motion in children with ACB is completely different from that of children with normal occlusion. The different motions might be related to morphological differences between the two groups.

DOI： 10.1179/crn.2010.003

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER IRELAND LTD  

The purpose of this study was to investigate the relationship between cephalometric nasal and skeletal landmarks in preschool children. Lateral cephalograms of 80 Japanese preschool children (40 boys, mean age 5.4 +/- 0.3 years; 40 girls, mean age 5.2 +/- 0.1 years; total mean age 5.3 +/- 0.3 years) were traced, and 22 skeletal and 3 soft-tissue nasal points were digitized. The coordinates from each subject were transformed to a standardized plane using a custom-made program written in Microsoft Visual C++(R). In this standard plane, sella was the origin, Frankfort Horizontal (FH) plane was parallel to the X-axis, and all 25 points were rotated to match this reference plane. The three nasal landmarks used in this investigation were: (1) rhi&apos;, the intersection point of a line parallel to the FH plane at rhinion and the facial line; (2) pronasale (Prn), the most anterior point on the nose: and (3) subnasale (Sn), the most posterior-superior point where the columella met the upper lip. An independent-groups t-test was used to test for sex differences of coordinates of the nasal landmarks and their related skeletal landmarks. Significance was set at p &lt; 0.05. A stepwise regression analysis determined how combinations of skeletal landmarks explained the location of the nasal landmarks. Only one skeletal coordinate (N(X)) and no nasal coordinates showed a significant difference between boys and girls. The coordinates of rhi contributed significantly to the location of rhi&apos; and Prn (except for the Y-coordinate of girls). Moreover A-point and ANS contributed to the location of Prn and Sn. For Sn, the X- and Y-coordinates of girls and the Y-coordinate of boys were related to lower incisor or dentoalveolar structure of the mandible. It appears that the nasal landmarks in preschool children can be predicted from selected skeletal landmarks, and there are no sex differences for the nasal landmarks in children. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

DOI： 10.1016/j.forsciint.2009.06.015

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：OXFORD UNIV PRESS  

Chi-square analysis showed that the frequency of this mutation did not differ statistically between the normal and mandibular protrusion subjects. Multilevel model analysis of the 101 cephalograms showed that the mutation reduced the linear measurements of the mandible. These findings suggest that P561T heterozygous mutation affects mandibular growth during early childhood, and this mutation in the GHR gene is hypothesized to function as an inhibitory factor in the process of mandibular growth.

DOI： 10.1093/ejo/cjp017

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MOSBY-ELSEVIER  

Introduction: Upper airway size is increasingly recognized as an important factor in malocclusion. However, children with Class III malocclusion are somewhat neglected compared with those with a Class II skeletal pattern. Therefore, the purpose of this study was to establish the characteristic shape of the oropharyngeal airway (OA) in children with Class III malocclusion. Methods: The sample comprised 45 children (average age, 8.6 +/- 1.0 years) divided into 2 groups: 25 with Class I and 20 with Class III malocclusions. OA size of each group was evaluated by cone-beam computed tomography. Cluster analysis, based on OA shape, redivided the subjects into wide, square, and long types. The distributions of Class I and Class III subjects were compared among the types. Results: The Class III group showed statistically larger OA area and width compared with the Class I group. Area was positively correlated with Class III severity. The square type included 84% of the Class I malocclusions but only 30% of the Class III malocclusions, indicating that the OA in Class III malocclusion tends to be flat. Conclusions: The Class III malocclusion is associated with a large and flat OA compared with the Class I malocclusion. (Am J Orthod Dentofacial Orthop 2009;136:318.e1-318.e9)

DOI： 10.1016/j.ajodo.2009.02.017

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER ACAD PEDIATRIC DENTISTRY  

The purpose of this case report is to describe the treatment outcome of a 4-year-old girl with a dentigerous cyst on the primary mandibular right second premolar of her caries-free mouth. Her primary predecessor was extracted and the lesion decompressed by using a removable appliance with a resin projection. The succeeding premolar had not developed further 8 months later, however, and had to be extracted. Crown formation of the succeeding premolar might have been interrupted by the presence of the cyst. To our knowledge, this is the earliest reported asymptomatic dentigerous cyst in the mandibular premolar region with a vital primary second molar. (Pediatr Dent 2009;31:294-7) Received April 17, 2008 vertical bar Last Revision August 23, 2008 vertical bar Revision Accepted August 29, 2008

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Journal of Clinical Pediatric Dentistry  

Objective: The aim of the present study was to estimate the amount of overlap in children with the primary dentition. Study design: The sample consisted of 20 Japanese boys between 3 and 5 years of age (mean age: 4years 10 months). Landmarks on their maxillary and mandibular dental models were digitized using a three-dimensional mechanical digitizer in a single coordinate system. Multilevel statistical models created best-fit polynomial curves to determine overbite, overjet and buccal height of all primary teeth and describe the dental arch forms. Results: No significant side differences were detected. The primary canine showed the largest overbite (1.87 mm) and buccal height (9.07 mm). The primary second molar exhibited the largest ovejet (2.76 mm). Buccal height was the least variable measurement. Conclusion: Occlusal relationships of the primary dentition were evaluated in 3-dimensions, establishing overlap variables for clinical diagnosis and treatment planning.

DOI： 10.17796/jcpd.33.3.3436400715r4m214

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHROMA INC  

The purpose of this study was to determine whether the development of masseter muscle activity at mandibular rest position is characteristic for different angle classifications. The sample consisted of 64 boys and 108 girls, aged ten to 18. Electromyographic (EMG) activity from the right and left masseter muscles was recorded using an EMG scanner. First or second order polynomials were used to separately model the age-related changes in resting muscle activity of each gender and Angle&apos;s classification. The EMG activity of Class I boys and girls were expressed in positive second order polynomials. The EMG activities of Class II and Class III subjects were expressed in first order polynomials, and the EMG levels in Class III subjects were lower than in Class II subjects. These results indicated that development of resting activity levels might distinguish and characterize the anteroposterior mandibular position relative to craniofacial region.

DOI： 10.1179/crn.2009.007

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHROMA INC  

The instantaneous center of rotation has been used to describe sagittal plane kinematics of mandibular opening and closing. Although, lateral excursions are also important because the closing pathways of masticatory movements frequently coincide with those of lateral excursions with occlusal contacts, there are no similar descriptions of mandibular lateral excursions. To compensate for this deficiency, lateral excursions of 20 women were recorded in this study. Reference points around each subject's mandible were tracked in three dimensions for each 0.1 mm interval of 3-D distance traveled by the incisor during the first 6.0 mm of lateral excursion. ICR was represented by the point that traveled the least 3-D curvilinear distance during each interval. To describe the entire series of intervals, a lateral excursion center was represented by the point with the smallest 3-D curvilinear distance throughout the excursive movement. In the results of this study, lateral excursions can be described as rotation around a single fixed lateral excursion center that is located close to the intercondylar axis, but 22 mm posterior to the initial position of the working side condyle.

DOI： 10.1179/crn.2008.035

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MOSBY-ELSEVIER  

Many researchers have attempted to clarify the complex relationships between stomatognathic function and craniofacial morphology. Most studies investigated the trajectories of incisal or condylar points and measured temporomandibular morphology projected onto 2-dimensional radiographic films. Although these methods provided valuable information, their diagnostic capabilities were limited. We introduce a new 4-dimensional (4D) analysis of stomatognathic function that combines the 3-dimensional (3D) computed tomography of the cranium and mandible, dental surface imaging with a noncontact 3D laser scanner, and mandibular movement data recorded with a 6 degrees of freedom jaw-movement analyzer. This method performs dynamic and precise simulations that can analyze and display condyle to fossa distances and occlusal contacts during mandibular function. These comprehensive relationships can be analyzed and displayed not only at intercuspal position, but also at any mandibular position during functional movements. We believe that our 4D analyzing system will be useful for diagnosing temporomandibular disorders of patients with jaw deformities and other malocclusions.

DOI： 10.1016/j.ajodo.2006.09.061

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHROMA INC  

In order to provide standard values for craniofacial growth of normal children, we evaluated the growth changes of skeletal and soft tissue cephalometric landmarks from lateral cephalograms of 180 Japanese children. They were divided into three groups: primary dentition, mixed dentition, and permanent dentition. Specific skeletal angles and distances showed significant gender differences with increasing age. The only significant soft tissue gender difference was nose height in the oldest group. Upper pharynx dimension and nose height differed significantly among the groups in both genders. Positions of both the upper and lower lip changed significantly between the intermediate and oldest groups of both genders. Nasolabial angle did not change significantly with growth. The results of this study should be useful for predicting craniofacial growth and development or determining the effect of orthodontic treatment.

DOI： 10.1179/crn.2008.023

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Language：English   Publishing type：Research paper (scientific journal)  

We introduce a new four-dimensional (4D) visualizing system of stomatognathic function that combines an individual's 3D head model, reconstructed from cephalograms, and mandibular movement data recorded with a six degrees-of-freedom jaw movement analyzer. The individual's head model was constructed by transforming a standard head model according to the 3D coordinate values calculated from the individual's cephalograms. The accuracy of the 3D reconstructed head model was determined. The error averaged 1.02%, with a range of 0.39-1.58%, and the accuracy was sufficient for clinical use. This method performs dynamic and precise simulation of mandibular movement. We believe that our system will be useful for evaluating the functional background of patients with malocclusions and maxillofacial deformities. © 2007 Elsevier Ltd and the Japanese Orthodontic Society.

DOI： 10.1016/j.odw.2007.07.001

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The purpose of this study was to look for associations between lower incisor movement and working and balancing condylar movement during lateral excursion in children with primary dentition and adults with permanent dentition. Mandibular movement was recorded using a TRI-MET (an optoelectronic analysis system with six degrees-of-freedom) at a sampling frequency of 100 Hz. The movement data was transferred to a graphics workstation for analysis. Subjects were categorized by age into two groups. The primary dentition group consisted of 19 children (mean age: 5 years and 5 months, s.d.: 8·7 months), and the permanent dentition group consisted of 22 women (mean age: 20 years and 5 months, s.d.: 26·3 months). The occlusion and TMJ in both groups were normal, with no history of orthodontic treatment. Three orthogonal excursive ranges and the 3D linear distance of the incisal and balancing and working condylar points, along with inter- and intra-individual correlations between the incisor and the balancing and working condyles during lateral excursion, were estimated by using multilevel statistical models. Lateral excursion in children with primary dentition was characterized by smaller incisor excursive ranges and 3D linear distance than in adults, and stronger inter- and intra-individual correlations between incisor and balancing condylar movements than in adults. In both children and adults the lateral excursion of the incisor was a good indicator of the extent of balancing condylar movement, but not working condylar movement. © 2007 Blackwell Publishing Ltd.

DOI： 10.1111/j.1365-2842.2006.01715.x

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHROMA INC  

The purpose of this study was to investigate the relationship between incisor and condyle movement during protrusion in children with primary dentition. Subjects were categorized into two age groups. A primary dentition group consisted of 20 children, and a permanent dentition group consisted of 25 women. The occlusion and TMJ in both groups were normal, with no history of orthodontic treatment. Three orthogonal excursive ranges, linear distance and curvilinear distance of the incisal and condylar points; sagittal angle of condylar rotation; and correlations between incisor and condyle distances during protrusion were estimated by using multilevel statistical models. Protrusion in children with primary dentition was characterized by: 1. significantly smaller superior-inferior ranges for incisal and condylar points in children than in adults; 2. strong positive correlations between incisor and condylar anterior-posterior ranges and linear distances, a pattern similar to that in adults.

DOI： 10.1179/crn.2007.015

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MOSBY, INC  

This article introduces a new method for 3-dimensional dental cast analysis, by using a mechanical 3-dimensional digitizer, MicroScribe 3DX (immersion, San Jose, Calif and TIGARO software (not yet released, but available from the author at hayasaki@dent.kyushu-u.ac.jp). By digitizing points on the model, multiple measurements can be made, including tooth dimensions; arch length, width, and perimeter; curve of Spee; overjet and overbite; and anteroposterior discrepancy. The bias of the system can be evaluated by comparing the distance between 2 points as determined by the new system and as measured with digital calipers. Fifteen pairs of models were measured digitally and manually, and the bias was evaluated by comparing the variances of both methods and checking for the type of error obtained by each method. No systematic errors were found. The results showed that the method is accurate, and it can be applied to both clinical practice and research.

DOI： 10.1016/j.ajodo.2004.07.039

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHROMA INC  

The purpose of this study was to investigate whether the pathways of habitual mouth opening and closing in children with anterior reverse bit-e in the early mixed dentition differed from those of children with normal occlusion. The two subject groups for this study were composed of ten children with anterior reverse bite (reverse bite group) and twelve children with normal occlusion (normal occlusion group), respectively. These movements were measured by an optoelectronic analyzing system with six degrees of freedom. Movements of the incisal point were projected on the sagittal plane to characterize the paths, and sagittal angles between the incisal path and the horizontal plane were calculated and compared. Opening and closing sagittal angles in the reverse bite group were almost equal over the entire pathway, indicating that the pathways of habitual mouth opening and closing were similar. In contrast, all opening and closing sagittal angles in the normal occlusion group were different, especially close to maximum intercuspation, indicating that their pathway of habitual mouth opening differed from their mouth closing pathway. In conclusion, children with anterior reverse bite in the early mixed dentition have different patterns of habitual mouth opening and closing movements than children with normal occlusion.

DOI： 10.1179/crn.2004.036

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BLACKWELL PUBLISHING LTD  

Understanding of the growth and development of mandibular function is indispensable to the diagnosis of functional disturbances during childhood. The purpose of this study was to clarify the characteristics of the occlusal phase during gum chewing in children with primary dentition. Chewing motion at the working molar of 14 children with primary dentition and 28 female adults was recorded optoelectrically, and the frontal and sagittal angles of their closing and following opening strokes were measured and compared. In children the closing strokes were entered more vertically and anteriorly than in adults, and the opening strokes shifted to the non-working side in adults but moved to the working side in children. The degree of variance also differed between the two groups; the variance of the frontal angle was larger than that of sagittal angle in adults, but the opposite was true in children. These results suggested that the chewing pattern in children during the occlusal phase is distinctly different from adults and the chewing movement in children is not always less stable than in adults.

DOI： 10.1111/j.1365-2842.2004.01263.x

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：W B SAUNDERS CO  

Purpose: We sought to compare mandibular motion during mastication in patients treated in either an open or a closed fashion for unilateral fractures of the mandibular condylar process.
Patients and Methods: Eighty-one male patients with unilateral condylar process fractures were treated either with (n = 37) or without (n = 44) surgical reduction and rigid fixation of their condylar process fractures. At 6 weeks, 6 months, 1 year, and 2 years after treatment, the subjects' chewing cycles were recorded using a magnetic sensor array (Sirognathograph; Siemens Corp, Bensheim, Germany) while chewing Gummi-Bears (HARIBO, Bonn, Germany) unilaterally on the same side as the fracture and on the opposite side. The chewing cycles were analyzed using a custom computer program, and the duration, excursive ranges, and 3-dimensional cycle shape were compared between the 2 treatment groups at each time interval using multilevel linear modeling statistics.
Results: The 2 treatment groups did not differ significantly for any measure of cycle duration or any excursive range (except lateral excursions at 1 year post-treatment) at any of the time intervals. However, the 3-dimensional cycle shapes of the 2 groups did differ significantly at all time intervals.
Conclusion: Surgical correction of unilateral condylar process fractures has relatively little effect on the more standard measures (duration and excursive ranges) of masticatory function. However, surgical correction better normalizes opening incisor pathways during mastication on the side opposite the fracture. (C) 2004 American Association of Oral and Maxillofacial Surgeons.

DOI： 10.1016/j.joms.2003.01.003

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：QUINTESSENCE PUBL CO INC  

Purpose: This study observed occlusal contacts and determined their areas on the mandibular teeth, especially the molars, during voluntary lateral excursions. Materials and Methods: Occlusal contact areas were estimated with a measurement system combining 3-D tracking of mandibular movements with 3-D digitization of tooth shape. Sixteen women with sound permanent dentitions participated. Results: At the intercuspal position, estimated occlusal contact areas of the first and second mandibular molars were on average 12.6 mm(2) and 9.0 mm(2), respectively. However, after 3.0 mm of lateral excursion, their areas were sharply reduced to 2.2 mm(2) and 1.5 mm(2) on the working side, and 0.4 mm(2) and 1.1 mm(2) on the nonworking side, respectively. Conclusion: These results suggest that the occlusal contact areas on working- and nonworking-side molars differ from each other as lateral excursion proceeds.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MOSBY, INC  

This study compared the mandibular kinematics during mastication of patients treated for unilateral fractures of the mandibular condylar process with those of control subjects. We used a Sirognathograph (Siemens, Bensheim, Germany) to record the chewing cycles of 81 male patients with unilateral condylar process fractures while they chewed a constant bolus unilaterally on the same side as the fracture and on the opposite side. Recordings were made at 6 weeks, 6 months, 1 year, and 2 years after treatment. Similar chewing cycles were recorded for 15 male controls (Class I dental and Class I skeletal occlusion) without fractures of the condylar process. The chewing cycles of both groups were analyzed with a custom computer program, and the duration, excursive ranges, and 3-dimensional cycle shape were compared at each time interval with multilevel linear modeling statistics. Fracture patients had significantly slower chewing cycles, with significantly less maximum excursion toward the working side during the closing phase and significantly greater excursion toward the balancing side during the opening phase than the controls. The opening pathway of the incisors showed greater differences between patients and controls than the closing pathways. Differences in chewing cycle shape persisted for up to 2 years, especially when chewing was on the side opposite the fracture. Unilateral condylar process fractures produce long-lasting changes in chewing cycle duration and chewing cycle shape of adults.

DOI： 10.1016/j.ajodo.2003.03.002

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BLACKWELL PUBLISHING LTD  

Chewing is one of the most important functions of the mandible, but, to date, there are very few studies of this function in children. The purpose of this study was to quantify the length of the occlusal glide at the lower incisal point during gum chewing in children with primary dentition. Eleven girls with primary dentition were selected for this study. Mandibular excursions with occlusal contacts and gum chewing movement were measured using an optoelectronic system that can measure mandibular movement with six degrees-of-freedom at a sampling frequency of 100 Hz. A curved mesh diagram of incisor coordinates during mandibular excursions was established to calculate the length of the occlusal glide for each subject. The occlusal glide lengths of children were compared with previously reported results for adults. The estimated length of the occlusal glide during closing was significantly shorter in children than in adults, contrary to that during opening. This result suggests that children have a characteristic chewing pattern that differs from adults.

DOI： 10.1046/j.1365-2842.2003.01162.x

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BLACKWELL PUBLISHING LTD  

The occlusal phase of chewing is especially interesting because food particles are being pulverized in this phase. For efficient chewing the upper and lower teeth must come together in a congruent fashion with less variation than in other phases. To examine this expectation the chewing motions of 28 women were recorded optoelectrically, and their frontal and sagittal angles of the closing and following opening strokes were measured at 3.0 mm ( 3- D linear distance) of opening. Closing strokes were more stable than opening strokes. The frontal angle was correlated with the sagittal angle during closing. The opening and closing sagittal angles were moderately correlated, and the opening and closing frontal angles were negatively correlated at the intersubject level. No direct association was found between the closing strokes and following opening strokes at the intra- subject level. These results suggest that closing strokes are more stable than opening strokes, resulting in efficient mastication.

DOI： 10.1046/j.1365-2842.2003.01182.x

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BLACKWELL PUBLISHING LTD  

Aims Type 2 diabetes is known to affect alveolar bone loss (ABL). The purpose of this study was to examine whether impaired glucose tolerance (IGT) is associated with ABL, as is diabetes.
Methods A case-control study was performed with 664 Japanese men aged 46-57 years. Panoramic radiographs revealed 513 severe ABL cases, 22 moderate ABL cases, and 129 controls with good alveolar bone. Diabetes status was classified into normal glucose tolerance (NGT), impaired fasting glucose (IFG), IGT, and newly diagnosed diabetes according to the fasting plasma glucose and 75-g oral glucose tolerance test (OGTT). Diabetes under treatment was excluded. Odds ratios (ORs) and 95% confidence intervals (CIs) were obtained from ordinal logistic regression analysis. Statistical adjustment was made for total cholesterol, HDL-cholesterol, triglyceride, rank in the Self Defence Forces (SDF), cigarette-years, alcohol use, body mass index, previous 10 years' brushing habits and instrument use other than toothbrush, and history of periodontal treatment.
Results A significant, approximately three-fold increase in the crude OR (crude OR = 3.28; 95% CI = 1.16-9.27) and non-significant 2.6-fold increase in the adjusted OR (adjusted OR = 2.55; 95% CI = 0.86, 7.54) of ABL was observed among men with newly diagnosed Type 2 diabetes compared with the reference group (NGT combined with IFG). However, there was no association between IGT and ABL (adjusted OR = 0.99; 95% CI = 0.59,1.64).
Conclusions Type 2 diabetes, but not IGT, was positively associated with ABL. Preventive maintenance against periodontitis is important in middle-aged men with diabetes.

DOI： 10.1046/j.1464-5491.2003.00989.x

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Journal of Clinical Pediatric Dentistry  

Sound development of mandibular function during childhood is indispensable to establishing healthy function in adults. To examine this developmental process, longitudinal recordings of basic mandibular movements were done using an optoelectronic analysis. Mandibular movements were recorded on five separate occasions in one boy, from an age of six years and five months to 14 years and five months. The incisor pathways during protrusion and lateral excursion were initially shallow, with more anterior than inferior movement, but as he grew the amount of inferior movement and the amount of rotation both increased. Similarly, at his first recording there was very little hinge-like rotation during mouth closing, but rotation increased markedly after eruption of his permanent second molars. These findings suggest that mandibular movements change from being relatively simple with more translation in younger children to more complex movements with more rotation once the permanent dentition is established.

DOI： 10.17796/jcpd.27.4.c4079073ug20w68m

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BLACKWELL PUBLISHING LTD  

The purpose of this study was to estimate the length of the occlusal glide during gum chewing at the lower incisal point. Mandibular excursions with occlusal contacts in 25 females with permanent dentition were recorded using an optoelectronic system that can measure mandibular movement with 6 d.f. at a sampling frequency of 100 Hz. A curved mesh diagram of incisor coordinates during maximum mandibular excursions (CMDME) was plotted. Gum chewing movement was also measured using the same system and computer software which divided the chewing movement into cycles at each maximum opening position. Each cycle was standardized at 0.1 mm intervals from the most closed position. Finally, the distance between the CMDME and each position of the incisor during a chewing cycle was calculated. Whenever, this distance was less than 0.2 mm opposing teeth were considered to be in contact. The occlusal glide was defined as the distance travelled by the lower incisal point as the mandible moved along occlusal contacts of the CMDME. The vertical coordinates at the beginning of the occlusal glide (during closing) and at the end of occlusal glide (during opening) were also calculated. The lengths of the occlusal glide pathway averaged 1.29 mm during closing and 1.55 mm during opening, a total length of 2.84 mm. Mean vertical coordinates at the beginning and end of the glide were -0.95 and -1.12 mm from inter-cuspal position, respectively.

DOI： 10.1046/j.1365-2842.2002.00949.x

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Language：English   Publisher：Japan Prosthodontic Society  

<b><i>Purpose</i> : </b>Determining the minimum opening position during chewing when food particles are being fractured and the variability of this minimum opening, which also affects the efficiency of the motion, are crucial for dentistry. This paper investigated estimates of the minimum opening position during gum-chewing movements and compared the variability of different mandibular reference points (i.e., lower incisal point, right and left molars). The variability between the maximum intercuspal position and the minimum opening position was also compared.<br><b><i>Materials and Methods</i> : </b>Twenty-eight young female subjects participated in this study. The gum-chewing motion of each subject was recorded using an optoelectronic analysis system with six degree-of-freedom. Minimum opening position was defined as the position where the lower incisal point reached its uppermost position between two maximum opening positions.<br><b><i>Results</i> : </b>The three reference points at the minimum opening position were located more posteriorly compared with their position at the maximum intercuspal position. The minimum opening position of the molars was more stable than that of the lower incisal point, and the molar had less variability on the working side than on the balancing side. In the lateral direction, the mandibular position at the maximum intercuspal position was less stable than at the minimum opening position during chewing.<br><b><i>Conclusion</i> : </b>The minimum opening position was not coincident with the maximum intercuspal position. In addition, its reproducibility was relatively higher than the maximum intercuspal position, especially in the lateral direction, suggesting that closer attention must be paid to lateral deviation of bite registration at the maximum intercuspal position.

DOI： 10.2186/prp.1.66

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Other Link： http://search.jamas.or.jp/link/ui/2003141795

Language：English   Publishing type：Research paper (scientific journal)   Publisher：BLACKWELL PUBLISHING LTD  

This study investigated how jaw kinematics, including cycle duration, three-dimensional (3-D) excursive ranges and velocities, and cycle shape, changed with increasing hardness of chewing gum. Twenty-six subjects (13 males and 13 females; mean age 23.6 +/- 2.5 years) with Class I normal occlusion were asked to chew two brands of gum with differing hardness. Jaw motion during chewing was tracked with an Optotrak(R) camera at 100 Hz, and all movements were recorded as pure 3-D mandibular movements relative to Frankfort horizontal. Cycle duration did not change significantly with harder gum, but 3-D excursive ranges and velocities increased, except during the occlusal phases of the chewing. Cycle shape was similar for hard and soft gum, but the overall size of the cycle was larger with hard gum. These results suggest that greater muscular effort when chewing harder gum produces a greater acceleration of the mandible in all phases except when the harder gum slows the mandible during the occlusal phases.

DOI： 10.1046/j.1365-2842.2002.00862.x

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHROMA INC  

Normal development of primary and mixed dentition is indispensable for establishing a healthy mandibular function of the permanent dentition. Because condylar movements are crucial for mandibular function, extensive studies have been reported. However, most of these studies have dealt with mandibular functions in adults, and there is less known about children with primary dentition. The purpose of this study was to clarify the condylar movements during lateral excursions in children with primary dentition and compare these movements with those of adults from the viewpoint of functional development. With use of an optoelectronic recording system with six degrees of freedom, the lateral excursions of 24 children and 20 young women, with sound dentition, were recorded at 100 Hz. The results show that the balancing side condyle of the children had a significantly smaller vertical excursion and a significantly larger anteroposterior excursion than that of adults, indicating the shallower and more anteriorly directed movements of the entire mandible during lateral excursions in children with primary dentition.

DOI： 10.1080/08869634.2002.11746208

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This case report examines jaw motion during both habitual opening-closing and gum chewing in a young (3 years, 10 months) patient with unilateral crossbite at the primary dentition stage. Jaw motion was measured three times: 1. before treatment; 2. after active treatment; and 3. after retention. The abnormal habitual open-close pathway seen prior to treatment was improved after retention. Prior to treatment, movement of the affected-side condyle preceded movement of the non-affected-side condyle during opening. After retention, the movement of the condyles was better coordinated. The chopping type chewing pattern, with less lateral movement, before treatment changed to a more grinding type pattern on the affected side after activation. This study suggests that the prescribed treatment effectively improved both the patient's morphology and function. However, neither the open-close pathways nor the chewing patterns were completely normal after retention. The results in this case suggest that early treatment of functional unilateral crossbite can be effective.

DOI： 10.1080/08869634.2002.11746202

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BLACKWELL PUBLISHING LTD  

The purpose of this study was to evaluate whether the path of habitual mouth opening was influenced by anterior reverse bite malocclusion in children. Two groups of children with the primary dentition were chosen: (i) 10 children with anterior reverse bite (reverse bite group) and (ii) 10 with normal occlusion (normal occlusion group). Their habitual mouth opening movements were measured by an opto-electronic movement-analysing system with 6 d.f. at a sampling rate of 100 Hz. These movements were projected on the sagittal plane at the incisal and condylar points. To characterize the path, we used the angles between the path and the horizontal plane. in the initial stage of opening, the incisal path of the reverse bite group was displaced more posteriorly from the intercuspal position than that of the normal occlusion group. However, as opening continued, the direction of the path of the reverse bite group was more anterior than those of the normal occlusion group. During the entire opening movement, the condylar path of the reverse bite group was flatter than those of the normal occlusion group. in conclusion, it was demonstrated that anterior reverse bite in the primary dentition clearly affects the paths of habitual opening movements.

DOI： 10.1046/j.1365-2842.2002.00785.x

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MOSBY, INC  

In a previous study, we established that young children with unilateral posterior crossbite have a longer mandibular ramus and more superiorly and posteriorly positioned condyles on the crossbite side. In this study, we evaluated chewing cycle shape and duration in 14 of the patients before treatment, and we looked for changes in cycle shape and duration 6 months after treatment with rapid palatal expansion. Mandibular kinematics was recorded while chewing gum using an optoelectric recording system at 100 Hz. Subjects were asked to chew normally for 20 cycles, chew on the crossbite side only for 20 cycles; and chew on the noncrossbite side only for 20 cycles. A special computer program selected the 10 most representative cycles from each series and computed an average duration and an average maximum excursion along 3 orthogonal axes. Multilevel linear models were used to generate an 8th-order polynomial describing average cycle shape and to test for statistically significant differences in shape between the patients and the controls and between the patients before and after treatment. Before treatment, the patients chewed more slowly than did the controls. Treatment shortened their cycle duration to equal control values. Before treatment, the patients also had larger maximum excursions than did the controls and exhibited a reverse-sequence cycle shape when chewing on the crossbite side. Treatment did not alter the patients' abnormal cycle shape: These results suggest that some features of the masticatory kinematics respond to orthodontic treatment alone, but others do not.

DOI： 10.1067/mod.2001.118626

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHROMA INC  

Translation and rotation of the mandible during habitual mouth opening movements were studied in 13 children with skeletal-based anterior reverse bite (reverse bite group) and in 13 children with normal occlusion (normal occlusion group) whose dental stage was the primary dentition. Movements were recorded by an opto-electronic movement-analyzing system that could measure mandibular movements with six degrees of freedom. Inferior translation of the mandible was analyzed at the left primary central incisor, both of the primary canines, and both of the primary second molars. Anterior translation of the mandible was analyzed at both of the condyles. Rotation of the mandible was measured in the sagittal plane. The results showed that the associations between the translation and rotation of the mandible during habitual mouth opening in the reverse bite group differed from those in the normal occlusion group. The reverse bite group had greater anterior translation of both of the condylar points than did the normal occlusion group. No significant differences were found in the inferior translation or rotation of the mandible between the two groups.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BLACKWELL SCIENCE LTD  

The purpose of this study is to provide basic understanding of how the speed of chewing affects masticatory jaw kinematics. Twenty-six healthy subjects (23.6 +/- 2.5 years of age) chewed a standardized bolus of gum at fast (100 cycles s(-1)), habitual and slow (50 cycles s(-1)) rates. The rates were controlled with a metronome and the order of rates was randomized for each subject. An optoelectrical system independently recorded head and jaw movement. Special computer programs identified representative cycles for each subject and computed various aspects of jaw movement. Multilevel statistical procedures were used to compare cycle variables among the three rates, estimate variability and model jaw movements. Maximum ranges of anteroposterior (AP), vertical and lateral jaw excursions were significantly less for the fast than the habitual or slow rates. While the shape of 3-D pathway was similar for the three rates, the perimeter of the pathway was significantly shorter for fast chewing cycles. Maximum AP, vertical, lateral and total 3-D jaw velocities were significantly different among the three rates. Between cycle variation in cycle duration and jaw excursion were least during fast chewing and the greatest during slow chewing; variability in maximum velocity was similar for the three rates.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

This study evaluated the correlations between condylar translation and incisor movements during maximum protrusion and lateratrusion. The sample was 27 adult females (23-35 years old), selected for normal temporomandibular function, occlusion, and skeletal patterns. Condylar and mandibular central incisor movements [linear distances (LD) and curvilinear pathways (CP)] were recorded in three dimensions for 20 s with an optoelectric (Optotrak(R)) jaw-tracking system while each participant performed multiple maximum protrusive and lateratrusive cycles. Masticatory analysis and multilevel statistical programs computed the three-dimensional movements of the incisors and condylar hinge axis during protrusion and lateratrusion, CP of the incisor point averaged 12.0 mm (9.3 mm LD) during protrusion, 13.0 mm (11.5 mm LD) during right excursion and 12.3 mm (11.0 mm LD) during left excursion. CP Of the condyles averaged 11.9-12.9 (9.2-9.5 LD) mm during protrusion. During lateratrusion the contralateral condyles moved anteroinferiorly 11.6-14.1 mm (9.5-10.2 mm LD); the ipsilateral condyles moved posterolaterally 5.8-6.8 mm (2.3-2.5 mm LD). The left condyles demonstrated more movement than the right condyles during protrusion and than the contralateral condyles during laterotrusion. Relative variation, as measured by the coefficient of variation, was greater for the movements of the ipsilateral than contralateral condyles. Incisor movements were only moderately related to condylar movements between individuals and between replicates; LDs showed stronger correlations than CPs; and correlations were stronger for lateratrusion than protrusion. While incisor and condylar movements were not affected by repeated protrusion, incisor CP (approx. 0.2 mm/cycle) and LD (approx. 0.1 mm/cycle) increased significantly with repeated excursive movements to the left and right. It was concluded that (1) incisor protrusion and lateratrusion provide moderately reliable measures of condylar translation: (2) the linear distances that the incisors move during lateratrusion provide the best measure of contralateral condylar translation: and (3) condylar movements are not affected by repeated protrusion or lateratrusion. (C) 2000 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0003-9969(00)00096-0

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BLACKWELL SCIENCE LTD  

Although previous studies have paid much attention to the condylar movement in adults with permanent dentition, little attention has been paid to such movement in children. In this study, we therefore clarified the difference in habitual open and close movements at the condyle in children . Three groups of subjects were used; primary (10 children), early mixed (10 children), and permanent dentition (10 adults). The habitual open and close mandibular movement of each subject was measured using a TRIMET, which can three-dimensionally analyse the simultaneous movements of multiple points on the mandible of a subject. The measurements were then compared among the three groups. The three-dimensional analysis detected significant difference in all directions between children with primary dentition and adults with permanent dentition: primary dentition had the smallest anterior-posterior and superior-inferior directions, and the largest left-right direction. Coincidence of the open and close tracks occurred in the adults (adult group) but not in the children (primary and early-mixed dentition groups). The early-mixed dentition group showed tracks that were between those for the primary dentition group and the adult group. These results suggest that the regularity of the condylar track might be well established with dental development.

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Language：English   Publishing type：Research paper (scientific journal)  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER ASSOC DENTAL RESEARCH  

The presence of non-working occlusal contacts in adults is considered abnormal and may initiate parafunctional activity. Few studies have looked for non-working occlusal contacts in children with primary: dentition. The purposes of this study were (1) to prove the existence of non-working-side occlusal contacts, and (2) to quantify their area during lateral excursion in children with primary dentition. To achieve this purpose, wt developed a measurement system that combined II tracking system for mandibular movements with a three-dimensional digitizer for tooth shape. Ten children were selected for this study. Estimated occlusal contact area of the primary second molar on the non-working side was 0.8 mm(2), in contrast to 2.0 mm(2) on the working side, at 3.0 mm of movement of the lower incisor. All children examined had some occlusal contacts on the non-working side during the first part of lateral excursion.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

This study introduces new methods of quantifying and evaluating the human chewing cycle. These methods were validated on a sample of 26 young adults (11 women and 15 men) between 20-35 years of age. Movements of the mandibular central incisors were recorded (100 Hz) using an optoelectric computer system while the participants chewed gum. A subsample of 10 cycles was automatically selected, based on multiple objective criteria to ensure representative cycles for each individual. Once representative cycles had been identified, multilevel statistical models were used to evaluate and describe the sample's kinematic patterns. The multilevel procedures allow for missing observations, they do not assume equal intervals. and variation can be partitioned hierarchically. Two-level models showed significantly shorter cycle duration for males (835 msec) than females (973 msec). Inferior-superior (IS) cycle range was 2.6 mm larger and maximum LS velocity was 19.6 mm/sec faster in males than females. There were no significant differences in medial-lateral (ML) and anteroposterior (AP) excursive ranges or velocities. With the exception of cycle duration and ML ranges of motion, random variation was three to five times larger between individuals than between cycles. The three-level models showed that eighth-order polynomials were necessary to describe IS, AP, and ML chewing movements of the entire cycle. The models identified highly significant sex differences in cycle kinematics (excursions, velocities, accelerations, etc.) for each aspect of movement (AP, IS, and ML). It is concluded that this;approach provides several important advantages over existing methods, including (a) its objectivity, (b) a more complete description of kinematic patterns, (c) a hierarchical description of variation, and (d) its ability to test hypotheses statistically, (C) 2000 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0003-9969(00)00015-7

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

This study evaluated the common clinical assumption that condylar translation and mouth opening at the incisor are closely related. The sample studied comprised 27 adult females (23-35 years), selected for normal temporomandibular function, occlusion, and skeletal patterns. Condylar and mandibular central incisor movements (straight-line distances and curvilinear pathways) were recorded in three dimensions (3D) for 20 s with an optoelectric (Optotrak(R)) jaw-tracking system while each participant performed multiple maximum opening cycles. Masticatory analysis and multilevel statistical programs computed the 3D movements of the incisors and condylar hinge axis during opening and closing. The incisor point moved an average straight-line distance of 46.6 mm during opening and 45.9 mm during closing, the lengths of the opening and closing curvilinear pathways were 48.6 and 47.7 mm, respectively. The condyles moved average straight-line distances of 11.9 and 12.2 mm during opening and closing, respectively. The condyles' curvilinear pathways during opening and closing were 14 and 14.6 mm, respectively. Ranges of condylar movement varied widely between individuals. The straight-line distances and curvilinear pathways were highly correlated for the incisors (R = 0.98) and the condyles (R = 0.98). Neither the straight-line distances nor curvilinear pathways of the incisors were correlated with those of the condyles. Incisor straight-line distances and curvilinear pathways were moderately correlated with mandibular rotation (R-between (subjects) = 0.82 and R-between (repeats) = 0.88) During repeated openings, both condylar and incisor excursions increased, but during repeated closings only incisor excursions increased. It is concluded that (1) maximum incisor opening does not provide reliable information about condylar translation and its use as a diagnostic indicator of condylar movement should be limited, (2) healthy individuals may perform normal opening with highly variable amounts of condylar translation, (3) the straight-line distances of the incisor and condyles provide adequate information about the length of the curvilinear pathway, and (4) variation in maximum incisor opening is largely explained by variation in the amount of mandibular rotation. (C) 2000 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0003-9969(99)00140-5

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BLACKWELL SCIENCE LTD  

The purpose of this study was to develop a method for calculating the range of the occluding phase in chewing movements. In this study, we defined 'range' as the distance of the movement at the lower incisal point while the mandible moves with tooth contact. First, mandibular excursions were measured using an opto-electronic movement analysis system, which can measure mandibular movement with six degrees-of-freedom at a sampling frequency of 100 Hz. With use of this measurement data, the curved mesh diagram of mandibular excursion (CMDME) previously reported was made. Then, chewing movements were measured using the same analysis system. The movements were separated into their component chewing cycles. Finally, we calculated the distance between each cycle and the CMDME. The occluding range of our subject was 0.4 mm at the closing phase and 3.4 mm at the opening phase. These results suggest that tooth contact occurs during chewing movement and demonstrate that the range of the occluding phase for the opening and closing phases of a subject can be calculated without morphological data from a dental cast.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BLACKWELL SCIENCE LTD  

The CMDME (curved mesh diagram of mandibular excursion) method was developed for easy visualization and diagnosis of mandibular movement. This method uses measured mandibular movement to produce a diagram of the range, shape, and inclination of mandibular excursion in three dimensions using any arbitrary landmark of the mandible. First, the mandibular movement of a subject was measured by an opto-electronic movement analysis system capable of measuring mandibular movement with six degrees-of-freedom at a sampling frequency of 100 Hz. For the measurement, the subject was initially instructed to perform four repetitions of mandibular excursion at will, with tooth contact, each lasting 30 s. A total of 12 000 positions of the mandible were thus obtained. Secondly, an attempt was made to match these positions to intersection points (0.1 mm apart) of a CMDME (i.e. mesh) for arbitrary mandibular landmarks with intercuspal position at the origin. The CMDME method can visualize mandibular excursion, and can be used to compare several landmarks, different subjects, or different times. This makes this method an effective diagnostic tool for mandibular movement.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BLACKWELL SCIENCE LTD  

This study characterizes the mandibular protrusive and lateral excursions of children with primary dentition. With use of a Selspot(R) system, the protrusive and lateral excursions of nine children with the primary dentition and nine adults with the permanent dentition were measured and compared. This system was able to analyse the simultaneous movements of multiple points on the mandible of a subject in three dimensions. Furthermore, the system proved appropriate for use in young children because of the small burden imposed on them during the measurements. Using this subject-friendly system, the directions of the mandibular excursion for five reference points on the mandibular dental arch at each measurement distance (i.e. at 0.5 mm intervals) for three projected angles (frontal, sagittal and horizontal) were calculated. From the results it was found that the excursions of the primary dentition can move more horizontally and more forward with small descent compared with the permanent dentition. The underlying reason for these findings may be physiological growth, maturation, and adaptation of the occlusal function.

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Language：Japanese   Publisher：(公社)日本小児歯科学会  

複数の下顎任意点について三次元的に同時解析が可能な下顎多点運動解析システムを用いて,ヘルマンの歯年齢2A(男児3名,女児6名),3A(男児2名,女児7名)の小児,および成人(男9名)の前方滑走運動を計測し解析を加えた.歯年齢2Aおよび3Aの小児では,成人より矢状面投影角が有意に小さく,下方への動きが少なく浅い運動をしていた.前頭面投影角は歯年齢2A,3A,成人と順次大きくなり,前方滑走時の左右への偏位が減少していた.また,歯年齢2Aの矢状面投影角では,オーバーバイト,オーバージェットと有意な正の相関が認められたが,歯年齢3Aでは,水平面投影角とオーバージェットの間で負の相関が見られ,オーバージェットが下顎の左右への偏位を規制していると考えられた.歯年齢3Aは,歯年齢2Aと成人の移行型と思われる運動をしていた

DOI： 10.11411/jspd1963.29.2_379

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Other Link： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=1991&ichushi_jid=J00647&link_issn=&doc_id=19870146610011&doc_link_id=10.11411%2Fjspd1963.29.2_379&url=https%3A%2F%2Fdoi.org%2F10.11411%2Fjspd1963.29.2_379&type=J-STAGE&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00007_2.gif

DOI： 10.11411/jspd1963.29.3_569

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DOI： 10.11411/jspd1963.27.2_522

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Language：Japanese   Publisher：新潟歯学会  

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Language：Japanese   Publisher：(一社)日本障害者歯科学会  

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Language：Japanese   Publisher：(公社)日本小児歯科学会  

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Language：Japanese   Publisher：東京臨床出版(株)  

現在の日本人小児の乳歯と永久歯の萠出時期、萠出順序、第一大臼歯と中切歯の萠出パターンを明らかにするとともに、1988年に小児歯科学会が行った前回調査結果と比較することで、日本人の乳歯・永久歯の萠出に変化が生じているか否かについて検討した。前回調査に準じた方法で全国的調査が行われ、調査対象児は、歯の萠出時期に影響を及ぼし、歯種判定困難、萠出判定困難に関連する全身疾患を有するものを除外し、乳歯に関しては生後3ヵ月から47ヵ月(3歳11ヵ月)、永久歯に関しては4歳0ヵ月から18歳11ヵ月の健常な日本人小児39549人とした。乳歯の分析対象は0〜3歳(男児4404人、女児4320人)、永久歯の分析対象は4〜18歳(男子15308人、女子15517人)であった。最初に萠出する乳歯である下顎乳中切歯の萠出時期が男児は6.8ヵ月(前回調査では8.0ヵ月)、女児は7.5ヵ月(前回調査では9.0ヵ月)と有意に早くなっていた永久歯の平均萠出年齢に関しては、前回調査と比較すると、男子では上下顎の第一小臼歯、第二小臼歯、第一大臼歯で本調査結果の方が有意に遅かった。乳歯の萠出時期のばらつきに関しては、標準偏差を比較すると、男児では全ての歯種に、女児では上顎乳側切歯を除き全ての歯種に今回調査が前回調査より大きい値を示した。萠出時期の最小-最大月齢の幅は、下顎の第一乳臼歯と第二乳臼歯を除いて男児より女児の方が小さかった。日本人の乳歯の萠出は前回調査より個人差が拡大している傾向がうかがわれた。また、永久歯の萠出時期のばらつきも大きくなっている傾向が明らかとなった。

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Language：Japanese   Publisher：(公社)日本小児歯科学会  

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Language：Japanese   Publisher：日本顎口腔機能学会  

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Other Link： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2020&ichushi_jid=J02994&link_issn=&doc_id=20210517470015&doc_link_id=10.7144%2Fsgf.26.120&url=https%3A%2F%2Fdoi.org%2F10.7144%2Fsgf.26.120&type=J-STAGE&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00007_3.gif

Language：Japanese   Publisher：(公社)日本小児歯科学会  

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Language：Japanese   Publisher：新潟歯学会  

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Language：Japanese   Publisher：(一社)日本障害者歯科学会  

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Language：Japanese   Publisher：(一社)日本障害者歯科学会  

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Language：Japanese   Publisher：(公社)日本小児歯科学会  

日本人永久歯の萠出時期、萠出順序および第一大臼歯と中切歯の萠出パターンを明らかにし、約30年前と比べて永久歯の萠出に変化があるか否かを検討する目的で、4歳0ヵ月から18歳11ヵ月の小児30,825人を調査し、以下の結果を得た。1.男子の萠出は、1が5歳6ヵ月-7歳0ヵ月、6が5歳10ヵ月-7歳6ヵ月、1が6歳6ヵ月-7歳10ヵ月、2が6歳3ヵ月-8歳3ヵ月、6が5歳11ヵ月-8歳7ヵ月、2が7歳6ヵ月-9歳2ヵ月、3が9歳2ヵ月-11歳3ヵ月、4が9歳1ヵ月-11歳7ヵ月、4が9歳5ヵ月-11歳6ヵ月、3が9歳10ヵ月-12歳1ヵ月、5が10歳4ヵ月-13歳0ヵ月、5が10歳3ヵ月-13歳2ヵ月、7が11歳3ヵ月-13歳10ヵ月、7が12歳1ヵ月-14歳5ヵ月の順であった。2.女子の萠出は、1が5歳5ヵ月-6歳7ヵ月、6が5歳6ヵ月-7歳0ヵ月、1が6歳3ヵ月-7歳7ヵ月、2が6歳3ヵ月-7歳8ヵ月、6が5歳10ヵ月-8歳4ヵ月、2が7歳2ヵ月-8歳8ヵ月、3が8歳8ヵ月-10歳5ヵ月、4が8歳11ヵ月-11歳0ヵ月、4が9歳1ヵ月-11歳1ヵ月、3が9歳2ヵ月-11歳4ヵ月、5が10歳1ヵ月-12歳11ヵ月、5が10歳2ヵ月-13歳1ヵ月、7が11歳2ヵ月-13歳10ヵ月、7が11歳9ヵ月-14歳3ヵ月の順であった。3.萠出順序は、男女ともに上顎が6≒1→2→4→3→5→7で、下顎が1→6→2→3→4→5→7であった。4.第一大臼歯と中切歯の萠出パターンは、男子では上顎がM型77.2%、I型22.8%で、下顎がM型29.2%、I型70.8%であった。女子では上顎がM型73.4%、I型26.6%で、下顎がM型36.7%、I型63.3%であった。5.萠出時期の性差は、すべての歯種で女子が早く萠出しており、上下顎1、2、3、4および6に有意差が認められた。6.約30年前に比べて、男子は上下顎4、5、6が、女子は3、上下顎の4、5、6、7の萠出時期が有意に遅くなっていた。(著者抄録)

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Language：Japanese   Publisher：(公社)日本小児歯科学会  

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Language：Japanese   Publisher：(公社)日本小児歯科学会  

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Language：Japanese   Publisher：(公社)日本小児歯科学会  

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Language：Japanese   Publisher：(公社)日本小児歯科学会  

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Language：Japanese   Publisher：(公社)日本小児歯科学会  

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Language：Japanese   Publisher：(公社)日本小児歯科学会  

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Language：Japanese   Publisher：(公社)日本小児歯科学会  

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Language：Japanese   Publisher：(公社)日本小児歯科学会  

日本人乳歯の萠出時期および萠出順序を明らかにし、乳歯の萠出に変化が生じているか否かを検討する目的で、全国的に3ヵ月から3歳11ヵ月の小児8,724名を調査し、以下の結果を得た。1.男児の乳歯萠出は、下顎乳中切歯が5ヵ月-9ヵ月、上顎乳中切歯が7ヵ月-11ヵ月、上顎乳側切歯が9ヵ月-1歳2ヵ月、下顎乳側切歯が9ヵ月-1歳3ヵ月、下顎第一乳臼歯が1歳1ヵ月-1歳6ヵ月、上顎第一乳臼歯が1歳1ヵ月-1歳7ヵ月、上顎乳犬歯が1歳2ヵ月-1歳8ヵ月、下顎乳犬歯が1歳2ヵ月-1歳9ヵ月、下顎第二乳臼歯が1歳11ヵ月-2歳7ヵ月、上顎第二乳臼歯が2歳0ヵ月-2歳11ヵ月の順だったが、上顎乳側切歯・下顎乳側切歯間と下顎第一乳臼歯、上顎第一乳臼歯、上顎乳犬歯および下顎乳犬歯の間には有意な差は認められなかった。2.女児の乳歯萠出は、下顎乳中切歯が6ヵ月-9ヵ月、上顎乳中切歯が7ヵ月-11ヵ月、上顎乳側切歯が9ヵ月-1歳1ヵ月、下顎乳側切歯が9ヵ月-1歳2ヵ月、上顎第一乳臼歯が1歳1ヵ月-1歳7ヵ月、下顎第一乳臼歯が1歳1ヵ月-1歳7ヵ月、上顎乳犬歯が1歳3ヵ月-1歳9ヵ月、下顎乳犬歯が1歳4ヵ月-1歳9ヵ月、下顎第二乳臼歯が1歳11ヵ月-2歳7ヵ月、上顎第二乳臼歯が2歳1ヵ月-2歳10ヵ月の順だったが、下顎乳中切歯、上顎乳中切歯間、上顎乳中切歯・上顎乳側切歯間、上顎乳側切歯・下顎乳側切歯間、下顎第一乳臼歯・上顎第一乳臼歯間、上顎乳犬歯・下顎乳犬歯間には有意な差は認められなかった。3.性差は大部分の歯で認めず、上顎乳犬歯と下顎乳犬歯の萠出時期にのみ有意な差を認め、いずれも男児が1ヵ月早く萠出していた。4.前回報告(1988年)に比べて、男児は上顎乳中切歯、下顎乳中切歯、下顎乳犬歯、下顎第一乳臼歯の、女児は下顎乳中切歯と下顎第一乳臼歯の、萠出時期が有意に早くなっていることを認めた。(著者抄録)

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Language：Japanese   Publisher：(一社)日本口蓋裂学会  

健常乳児の口蓋には吸啜窩が存在し、吸啜時に乳首を固定して哺乳を円滑にする役割を果たしている。口蓋裂児の哺乳機能を補うために口蓋床を装着する治療が行われるが、我々は口蓋裂児の口蓋形態を可能な限り健常児に近づけることで吸啜運動が活発になり効果的な吸啜が出来るようになるのではないかと仮説を立て、口蓋床に吸啜窩を付与するという改良を試みた。本研究の目的は口唇口蓋裂児の哺乳が円滑になることを目指し、従来の口蓋床(従来型)に吸啜窩を付与する(改良型)ことが吸啜時の舌運動に与える影響を検証することである。対象は口唇口蓋裂以外に吸啜力に影響を及ぼす病態のない口唇口蓋裂児8例で、口蓋裂児6例、口唇顎裂児2例であった。従来型と吸啜窩を付与した改良型で哺乳瓶哺乳を行い、超音波診断装置を用いて吸啜時の舌運動をB-modeで撮影した。解析にはDITECT社製、動画解析プログラム(DippMotionPro)を使用した。画像の舌表面に8ヶ所の計測点を設けて経時的に追尾させ、連続で得られた10吸啜波形について、各点の変位量と吸啜周期を計測し、吸啜窩付与前後で比較した。舌の総変位量は吸啜窩付与前・後で平均23.4±0.9mmから24.7±2.3mmへ増加した。吸啜窩付与により吸啜周期は0.78±0.04sから0.82±0.02sへ延長し、吸啜周期は安定した。改良型口蓋床で舌の変位量が増加したことから、口蓋床に吸啜窩を付与することは哺乳効率の向上に寄与する可能性が示唆された。(著者抄録)

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小児歯科臨床において、乳歯および幼若永久歯の外傷を主訴として来院する患者の割合が近年増加しているという報告がある。歯の外傷については、日本小児歯科学会発足当初から頻繁に研究課題としてとりあげられ、これまでに小児歯科学会雑誌に掲載された学会発表抄録は270編、総説・論文等は57編である。国外では、2012年にThe International Association of Dental Traumatology(IADT)が三編からなる診療ガイドラインを作成し、刊行誌であるDental Traumatologyに掲載した。これを受け2013年に、American Academy of Pediatric Dentistry(AAPD)は、その刊行誌であるPediatric DentistryにIADTの診療ガイドラインをAAPDの歯の診療ガイドラインとしてそのまま掲載した。そこで本稿では、日本小児歯科学会における歯の外傷に関するこれまでの報告等について集成し、診療ガイドライン作成の背景や意義を踏まえて検討するとともに、今後の方向性について考察を行った。(著者抄録)

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Other Link： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2014&ichushi_jid=J03252&link_issn=&doc_id=20141210250004&doc_link_id=%2Fae4chilj%2F2014%2F001712%2F006%2F0831-0834%26dl%3D0&url=https%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fae4chilj%2F2014%2F001712%2F006%2F0831-0834%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

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DOI： 10.11411/jspd.51.4_447

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Language：Japanese   Publisher：Japanese Society of Pediatric Dentistry  

As the birthrate continues to fall and extreme aging of the population progresses, the governmentand social systems tend to focus on aged individuals. However, health conditions during childhoodgreatly affect the presence or absence of dental problems in adulthood and the older years. Oralhealth and treatment in childhood are therefore extremely important. In this study, questionnaire surveyswere conducted regarding 1) the results of the 2010 revisions in payment for dental service, and2) the periodontal tissue examination of the mixed-dentition. Questionnaires were given to 130 executivemembers of the Japanese Society of Pediatric Dentistry, and analysis was performed on 58 memberswho responded (44.6%). The following results were obtained :1. Results of the revisions in the payment for dental service were considered &quot;very good&quot; by 3.5% ofrespondents, &quot;slightly good&quot; by 39.6%, &quot;quite bad&quot; by 5.2%, &quot;slightly bad&quot; by 17.2%, and &quot;no different&quot;by 34.5%, respectively.2. Comparing the total payment between this year and last year, there was a 1.7% increase in April, a0.6% decrease in May, and a 0.7% decrease in June.3. Causes for the increases in the total payment were given as &quot;an increase of the payment in firstand subsequent visits&quot; by 92.9% of participants, &quot;re-implementation of the additional payment forthose under 6 years old&quot; by 88.9%, and &quot;expansion of infant medical and dental expense aid in municipalities&quot;by 48.0%.4. Causes for decreases of the payment were given as &quot;a decrease in the number of visits by children&quot;by 55.6% of participants, and &quot;a decrease in dental caries&quot; by 52%. Furthermore, 39.1% recognizedthe introduction of &quot;the periodontal tissue examination of the mixed dentition&quot; as causing a decreasein the payment while 60.9% did not.5. Regarding the ratios of executing the various periodontal tissue examinations, the ratio of executingthe periodontal tissue examination of the mixed-dentition was 30.7% in April, 35.7% in May, and35.2% in June. The ratio of executing the basic periodontal examinations was 31.4% in April, 29.1%in May, and 29.8% in June. The ratio of not making an estimate was 37.9% in April, 35.2% in May,and 35.0% in June, which was more than one third.6. Regarding the amount of time required for examinations, &quot;the periodontal tissue examination of themixed dentition&quot; took roughly 7.3 minutes, &quot;the basic periodontal examinations&quot; took roughly 7.2minutes, and &quot;the complete periodontal examinations&quot; took roughly 13.3 minutes.7. Widespread implementation of the periodontal tissue examination of the deciduous- and mixeddentitionis necessary for prevention of periodontal diseases in adulthood. Examination methods touse during the deciduous- and mixed-dentition period and examination forms were devised.

DOI： 10.11411/jspd.49.1_20

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DOI： 10.11411/jspd.49.1_20

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Congenitally missing permanent teeth (CMPT) is one of the most frequent anomalies in dentistry. CMPT affects not only the occlusal relationships within the maxilla and mandible, but also the total occlusion. In addition CMPT can lead to future skeletal and facial problems. The purpose of this study was to estimate the nation-wide frequency of (CMPT) in Japanese children. Prior to beginning this epidemiological study, the authors obtained permission for the investigation from the ethics committee of Kagoshima University Graduate School of Medical and Dental Sciences (June 25&lt;sup&gt;th&lt;/sup&gt;, 2007).Seven pediatric clinics at dental colleges or universities and several private pediatric clinics participated in this study. The sample consisted of 15,544 pediatric dental patients (7,502 males and 7,502 females). Data were collected from longitudinal dental X-rays, orthopantomograms, and some dental models to determine CMPT (excluding 3&lt;sup&gt;rd &lt;/sup&gt;molars) within 6 months. All patients were judged to be over 7 years of age if they had all their permanent teeth in the dental films. In cases where it was difficult to judge the kind of tooth or its location, the committee members from all 7 colleges/universities reached a consensus on the number of missing teeth and their locations on a case by case basis.A total of 1,568 subjects (10.09%) were diagnosed with CMPT. Of these, 685 were males (9.13%),and 883 were females (10.98%). Differences between the maxilla and the mandible were seen in 4.37% of males and 7.58% of females. Differences between the right and left sides were seen in 0.11% of males and 0.14% of females. The most common missing tooth was the lower second premolar ; missing in 2.96% of adolescents, 2.64% of males (1.32% both sides) and 3.31% of females (1.72% on the right side and 1.59% on the left side). In descending order the next most common missing teeth were the mandibular lateral incisors, the maxillary second premolars, and the upper lateral incisors.

DOI： 10.11411/jspd.48.1_29

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The process of facial growth is of interest in dentistry, physical anthropology, and even industry. Several Japanese national institutes, e.g., the Advanced Industrial Science and Technology and the Research Institute of Human Engineering for Quality Life have measured and reported aspects of human body size and shape, including the facial morphology of children and adults. However, the facial morphology of infants was not included in these reports.In this study, three-dimensional facial morphological measurements of infants were performed using a three-dimensional laser surface-scanner system (VIVID 910, KONICA MINOLTA SENCING, Inc. Osaka, Japan). One hundred and twenty normal developing children (20 boys and 20 girls each at 4, 5 and 6 years of age) had their faces scanned by VIVID. Four widths (inter-Exocanthion width,inter-Endocanthion width, inter-Alar crest width and inter-Cheilion width) and 6 heights (Nasal height, upper facial height, mouth height, total facial height, lower facial height and Vermilion height) were measured.Most measurements increased with age in both boys and girls. Although significant sex-related differences were detected among the three age groups, there were no consistent tendencies. The infants&#039;growth rates for the measurements were not the same as those of adults from the literature. [I do not understand the next sentence. Perhaps you mean : &quot;For example, widths in the upper part of the face at four years of age are already 80% that of adults. Most measurements differed significantly between 5 and 6 years of age, but only 2 measurements differed significantly between 4 and 5 years of age. These results suggest that facial growth is not constant between 4 and 6 years of age, with rates affected by both age and sex. Further investigation may be required to elucidate characteristics of facial growth during childhood.

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Recording and analysis of normal patterns of growth and development of the human face are among the most important clinical observations. Three-dimensional digitization technologies can now record three-dimensional coordinates of facial surfaces, allowing direct analyses of landmark coordinates that provide the basis for statistical differences in facial shape during growth and development. The aim of this study was to compare methodologies used to establish the three-dimensional coordinate system for quantifying facial morphology.The three-dimensional facial morphology of infants was recorded using a three-dimensional laser surface scanner system (VIVID 910, KONICA MINOLTA SENCING, Inc. Osaka, Japan). One hun dred and twenty normal developing children (20 boys and 20 girls each at 4, 5 and 6 years of age) had their faces scanned by VIVID.Two origins and two reference planes for the scanned data were established and compared to evaluate the effectiveness and importance of the selected coordinate system. The first origin was at Nasion on the soft tissue, and the second was defined as the mid-point of both the right and left Endocanthion points. The first reference plane was a Nasal triangle based on three reference markers : soft tissue Nasion in the midline and Alar crests on each side. The second plane was based on 8 points,Exocanthion, Endocanthion, Alar crest and Cheilion on both right and left sides. The vertical axis was defined using 6 points : G, S, Prn, Ls, Li and Pog. The lateral axis was perpendicular to the vertical axis on the established plane, and the anterior-posterior axis had the same direction as the unit vector of the plane.The Endocanthion mid-point was the better origin, resulting in slightly smaller standard deviations and coefficients of variance of all measurements, especially on the vertical axis and three-dimensional distances. When the two reference planes were compared using this origin they differed for measurements in the sagittal plane by an average of 9.7 degrees. This angle decreased with growth, and a statistically significant difference was found between 4- and 6-year-old girls. No significant differences were detected on the horizontal plane.These results suggest that the selection of the coordinate system can influence observed measurements of growth, development and even treatment effects of the face. Therefore, the coordinate system should be chosen based on the purpose of the study and the characteristics of each landmark.

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Introduction: Upper airway size is increasingly recognized as an important factor in malocclusion. However, children with Class III malocclusion are somewhat neglected compared with those with a Class II skeletal pattern. Therefore, the purpose of this study was to establish the characteristic shape of the oropharyngeal airway (OA) in children with Class III malocclusion.
Methods: The sample comprised 45 children (average age, 8.6 +/- 1.0 years) divided into 2 groups: 25 with Class I and 20 with Class III malocclusions. OA size of each group was evaluated by cone-beam computed tomography. Cluster analysis, based on OA shape, redivided the subjects into wide, square, and long types. The distributions of Class I and Class III subjects were compared among the types.
Results: The Class III group showed statistically larger OA area and width compared with the Class I group. Area was positively correlated with Class III severity. The square type included 84% of the Class I malocclusions but only 30% of the Class III malocclusions, indicating that the OA in Class III malocclusion tends to be flat.
Conclusions: The Class III malocclusion is associated with a large and flat OA compared with the Class I malocclusion.

DOI： 10.1016/j.ajodo.2009.04.010

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A girl, aged 8-years and 10-months old, was brought to our hospital for treatment of the maxillary impacted supernumerary teeth. A radiographic examination revealed that the right maxillary central incisor was impacted, and two supernumerary teeth were located palatal to the left maxillary central incisor and nasally to the impacted right maxillary central incisor.&lt;br/&gt;&lt;br/&gt;The right maxillary central incisor was planned to be preserved in this patient. The left supernumerary tooth was first extracted, and through the extraction space, the right supernumerary tooth was exposed and removed. Orthodontic therapy was then performed using a maxilla fixing device and sectional arch to gradually bring the right maxillary central incisor to its proper position. Since the patient&#039;s family was planning to move in one year, multibrackets were used during this period to achieve favorable tooth position and occlusion.&lt;br/&gt;&lt;br/&gt;In this patient, it was difficult to bring the inverted and impacted central incisor to the proper position orthodontically. Thorough examination and good clinical skills were required to perform the or thodontic therapy, while preserving the dental pulp without damaging the root apex of the central incisor. The impacted supernumerary teeth had to be carefully removed to prevent damage to the central incisor.&lt;br/&gt;&lt;br/&gt;The patient and her parents were satisfied with the treatment outcome. In addition to promoting oral development, we were able to gain knowledge and improve our clinical skills.

DOI： 10.11411/jspd.47.1_111

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DOI： 10.11374/shonijibi.30.5

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Language：Japanese  

DOI： 10.11374/shonijibi.30.5

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Language：Japanese   Publisher：鹿児島大学歯学部  

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Other Link： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2009&ichushi_jid=J00245&link_issn=&doc_id=20090728030005&doc_link_id=http%3A%2F%2Fhdl.handle.net%2F10232%2F17018&url=http%3A%2F%2Fhdl.handle.net%2F10232%2F17018&type=%8E%AD%8E%99%93%87%91%E5%8Aw%81F%8E%AD%8E%99%93%87%91%E5%8Aw%83%8A%83%7C%83W%83g%83%8A&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F80042_3.gif

Language：Japanese   Publisher：Japanese Society of Stomatognathic Function  

DOI： 10.7144/sgf.14.100

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J-GLOBAL

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Language：Japanese   Publisher：日本顎口腔機能学会  

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Language：Japanese   Publisher：(公社)日本小児歯科学会  

DOI： 10.11411/jspd1963.44.2_162

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Language：Japanese   Publisher：(公社)日本小児歯科学会  

DOI： 10.11411/jspd1963.44.2_191

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Language：Japanese   Publisher：Japanese Society of Stomatognathic Function  

We introduce a new method of four-dimensional display of mandibular movement using the 3D-CT images of the skull and mandible, the dental surface image using a non-contact 3-D laser scanner and the mandibular movement data using a six-degree-of freedom-jaw movement analyzer. This method was employed to perform dynamic and precise simulation of the mandibular function for a patient with jaw deformity. The advantages of this system were as follows: 1. The dento-skeletal 3D image and the mandibular movement data were integrated on the same coordinates on a personal computer. The mandibular movement of multiple required points on the integrated images was displayed by the computer graphics, which make it possible clearly to grasp a relationship between the motion pattern of the mandibular movement, skeletal morphology and occlusion simultaneously. 2. This new method of analyzing the occlusal contacts and the condyle-fossa distance provides the comprehensive insight of the stomatognathic system not only at intercuspal position, but also at any mandibular positions during functional movement. 3. Our system to evaluate the intersection between morphology and function will certainly improve our understanding of the function of the temporpmandibular joint and occlusion. We believe that it is useful for diagnosing the temporomandibular disorders to patients with jaw deformities.

DOI： 10.7144/sgf.12.100

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Language：Japanese  

DOI： 10.7144/sgf.12.100

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Language：Japanese   Publisher：Japanese Society of Stomatognathic Function  

The purpose of this study was to characterize mandibular movement during protrusion in anterior crossbite children with primary dentition. Mandibular movements were measured using a TRI-MET^[○!R], an optoelectronic analysis system with six degrees-of-freedom, at a sampling frequency of 100Hz. This measurement data was transferred to a graphics workstation for analysis. The subjects with primary dentition were categorized into two groups according to their interocclusal relations, group one had normal occlusion and group two had anterior crossbite. The former group consisted of 20 children (mean age : 5 years and 6 months), and the latter group consisted of 15 children (mean age : 4 years and 9 months). Anterior-posterior range, right-left range, superior-inferior range and three-dimensional linear distance of the incisal point and the condylar points during protrusion were estimated by using multilevel statistical models. Correlation coefficients between incisor and condylar distances were evaluated at both the inter-individual and intra-individual levels. The study&#039;s results were : 1) Protrusion of the anterior crossbite group was characterized by smaller ranges and distances of both the incisors and condyles than children with normal occlusion. This suggests that when the teeth are at maximum intercuspal position the condyle is located more anteriorly in anterior crossbite children than in normal children. 2) High correlation coefficients in both groups of children, suggest that condylar movements during protrusion can be reliably estimated from incisor movements. 3) Intra-individual correlations of normal occlusion children were larger than their inter-individual correlations, but the reverse was true for anterior crossbite children.

DOI： 10.7144/sgf.12.37

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Language：Japanese   Publisher：(公社)日本小児歯科学会  

DOI： 10.11411/jspd1963.43.2_347

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Language：Japanese   Publisher：(一社)日本顎関節学会  

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J-GLOBAL

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Language：Japanese   Publisher：Japanese Society of Stomatognathic Function  

DOI： 10.7144/sgf.11.63

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Language：Japanese   Publisher：日本矯正歯科学会  

We introduce a new method for fourdimensional (4D) display of mandibular movement using the three-dimensional reconstructed computed tomography (3D-CT) of the skull and mandible, the dental surface image using a non-contact 3-D laser scanner, and the mandibular movement data using a six-degree-of freedom-jaw movement with the analyzer &quot;TRI-MET&quot;. This method was employed to perform dynamic and precise simulation of the mandibular function for a patient with jaw deformity. The advantage of this system were as follows : 1. The maxillofacial 3 D-CT image and the 3-D dental surface image were integrated on the same coordinates by using the ceramic balls as markers. The least squares method was employed to match morphological images in registration process. 2. The mandibular movement data were then converted to the same coordinates on the 3-D integrated image using the ceramic balls. The relationship between the motion pattern of the mandibular movement and the occlusal condition were visualized four dimensionally. 3. We believe that this new method to evaluate mandibular function by using computer graphics will be useful for diagnosing the temporomandibular disorders to the patients with jaw deformities. It provides easy-to-understand informations not to the orthodontists, but also the patients.

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Language：Japanese  

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Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

Recently, several attempts to investigate the relationship between facial skeleton and temporomandibular joint morphology, occulusal condition and the characteristics of mandibular movement have been made. As for temporomandibular disorder and jaw deformity, 3D understanding of mandibular structure and movement is generally important in diagnosis. However, traditional techniques do not allow total evaluation of jaw structure and movement as 3D information. In this study, we introduce a new method for four-dimensional(4D) display system of mandibular structure (3D) and movement(+1D). Jaw and teeth structure model are exactly constructed using 3D data from 3D-CT and 3D-LS (non-contact 3-D laser scanner), respectively. 6DOF jaw trajectory measured by a motion tracker (TRI-MET) is given to the structural model. Integration of the structure model and jaw movement is performed using reference spheres attached to the jaw and teeth. We also propose an automatic extraction and position detection of spheres in 3D data for integration in high accuracy. This method was employed to perform dynamical simulation of the mandibular function for patients with jaw deformities on a computer. By this system, we can visualize invisible inner movement of jaw using 3D image processing techniques.

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Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

Recently, several attempts to investigate the relationship between facial skeleton and temporomandibular joint morphology, occulusal condition and the characteristics of mandibular movement have been made. As for temporomandibular disorder and jaw deformity, 3D understanding of mandibular structure and movement is generally important in diagnosis. However, traditional techniques do not allow total evaluation of jaw structure and movement as 3D information. In this study, we introduce a new method for four-dimensional(4D) display system of mandibular structure (3D) and movement(+1D). Jaw and teeth structure model are exactly constructed using 3D data from 3D-CT and 3D-LS (non-contact 3-D laser scanner), respectively. 6DOF jaw trajectory measured by a motion tracker (TRI-MET) is given to the structural model. Integration of the structure model and jaw movement is performed using reference spheres attached to the jaw and teeth. We also propose an automatic extraction and position detection of spheres in 3D data for integration in high accuracy. This method was employed to perform dynamical simulation of the mandibular function for patients with jaw deformities on a computer. By this system, we can visualize invisible inner movement of jaw using 3D image processing techniques.

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Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

Recently, several attempts to investigate the relationship between facial skeleton and temporomandibular joint morphology, occulusal condition and the characteristics of mandibular movement have been made. As for temporomandibular disorder and jaw deformity, 3D understanding of mandibular structure and movement is generally important in diagnosis. However, traditional techniques do not allow total evaluation of jaw structure and movement as 3D information. In this study, we introduce a new method for four-dimensional(4D) display system of mandibular structure (3D) and movement(+1D). Jaw and teeth structure model are exactly constructed using 3D data from 3D-CT and 3D-LS (non-contact 3-D laser scanner), respectively. 6DOF jaw trajectory measured by a motion tracker (TRI-MET) is given to the structural model. Integration of the structure model and jaw movement is performed using reference spheres attached to the jaw and teeth. We also propose an automatic extraction and position detection of spheres in 3D data for integration in high accuracy. This method was employed to perform dynamical simulation of the mandibular function for patients with jaw deformities on a computer. By this system, we can visualize invisible inner movement of jaw using 3D image processing techniques.

CiNii Article

CiNii Books

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Language：Japanese  

DOI： 10.11411/jspd1963.42.2_326

J-GLOBAL

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Language：Japanese  

DOI： 10.11411/jspd1963.42.2_204

J-GLOBAL

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Language：Japanese  

DOI： 10.11411/jspd1963.42.2_248

CiNii Article

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Language：Japanese  

DOI： 10.11411/jspd1963.42.2_318

J-GLOBAL

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Language：Japanese   Publisher：(公社)日本小児歯科学会  

DOI： 10.11411/jspd1963.42.2_204

CiNii Article

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Language：Japanese  

DOI： 10.11411/jspd1963.42.2_248

J-GLOBAL

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