Language：English   Publisher：新潟歯学会  

本研究は新潟県内某市における施設入所高齢者の全身および口腔の健康に関わる因子のなかで、身体機能の低下、認知症、栄養摂取形態それぞれとの関連のある因子を明らかにすることを目的とした。そこで某市歯科医師会が歯科健診を行った介護保険施設・特定施設(18施設602名)から収集したデータを解析対象とし、障害高齢者の日常生活自立度(寝たきり度)、認知症高齢者の日常生活自立度および栄養摂取形態それぞれと全身健康状態の因子、口腔健康状態の因子との関連について、3つの二項ロジスティック回帰分析を用いて検討した。寝たきり度は、咬合支持(天然歯または義歯を含めた補綴物による両側咬合支持)(オッズ比(OR)=1.88;p=0.005)、嚥下(OR=3.47;p<0.001)、麻痺(OR=9.34;p<0.001)および認知症高齢者の日常生活自立度(OR=2.91;p<0.001)と有意に関連していた。認知症高齢者の日常生活自立度は、咬合支持(OR=3.21;p<0.001)および寝たきり度(OR=3.37;p<0.001)と有意に関連していた。栄養摂取形態は、咬合支持(OR=3.35;p<0.001)、口腔乾燥(OR=3.53;p<0.001)、嚥下(OR=3.50;p<0.001)、寝たきり度(OR=7.17;p<0.001)および認知症高齢者の日常生活自立度(OR=1.80;p<0.01)と有意に関連していた。以上の結果から、天然歯または義歯を含めた補綴物による両側咬合支持の喪失は、要介護高齢者の身体機能の低下、認知症および経管栄養を含む常食以外の栄養摂取形態と統計的に有意に関連していた。(著者抄録)

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

OBJECTIVE: To determine recent insurance claim rates for, facility income from, and the roles of professionals associated with management of nutrition, oral ingestion and oral health maintenance in long-term care insurance facilities (LTCIFs) in Niigata Prefecture. METHODS: A questionnaire on current staffing, oral health professional (OHP) utilisation, and claims for insured benefits for the investigated services was mailed to all LTCIFs in Niigata Prefecture, Japan (n = 304). Claim rates for and average facility income from these benefits were calculated. Facility income was compared between facilities with and without employed OHPs. Statistically significant factors associated with claims for investigated benefits were identified by logistic regression. RESULTS: Responses from 111 facilities indicated that they made insurance claims for nutrition management (95%), transition from tube feeding to oral ingestion (9%), basic maintenance of oral ingestion (39%), additional services for maintenance of oral ingestion (23%), oral health management system (68%), and oral health management (17%). Most facilities established collaborations with private dental clinics, but only 16% of facilities employed OHPs. Facility income was significantly higher (P = 0.005) for facilities that employed OHPs. OHP employment by facilities was associated with claims for four of the six benefits (P < 0.05). CONCLUSIONS: Most facilities consulted with private dental clinics, and 16% of the facilities employed dentists or dental hygienists to help residents manage oral ingestion problems and oral health maintenance. The facility income associated with management of these problems was significantly higher in facilities employing dental professionals.

DOI： 10.1111/ger.12376

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

Association between tooth morphology, occlusal relations and mandibular condyle/glenoid fossa morphology is still a controversial issue in dentistry. The aim of the present study was to examine the influence of three important articular parameters on the dental morphology and the crown volume, quantifying the variation for each tooth group: incisor, canine, premolar and molar. Materials and methods: All maxillary teeth from a set of basic study models were prepared for zirconia single crowns. The models were scanned and then, using a computer aided design software, they were mounted in a virtual articulator and specific mandibular movements were defined. The crown morphology was designed and statically adapted. Ten models were obtained by dynamical adjustment of the basic model for successively modified articular parameters: sagittal condylar inclination (SCI) = 30°, Bennett angle (BA) = 10°, Immediate side shift (ISS) = 0.5 mm — for control and SCI: 40°, 50° and 60° with BA and ISS as control, BA: 15°, 20° and 25° with SCI and ISS as control, ISS: 1.5 mm, 1.0 mm and 0.0 mm with SCI and BA as control — for the nine test models. The following measurements were performed three times on the right side of each model: volume for each tooth group, slope (S) for the central incisor, S and mesio-distal angle (MDA) for canine, S, MDA and vestibulo-oral angle (VOA) for the first premolar and molar. Results: When SCI was varied, statistically significant changes as compared to the controls were found for incisor's and premolar's S, premolar's VOA and, for 50° and 60°, MDA and molar's MDA (for 50°) and VOA (for 60°). When BA was varied, significant changes were found for S (canine) and, in certain models, MDA (premolar, molar). Variations of ISS significantly changed mainly MDA for molars and, in two models, premolars. Conclusions: Within the limits of this study, among the articular parameters, SCI mostly influenced the dynamic tooth morphology, but canine and molar morphology was stronger influenced by BA and/or ISS.

DOI： 10.1016/j.aanat.2018.02.013

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OBJECTIVES: To examine the associations among alcohol consumption level, dietary intake and other lifestyle factors, and periodontal condition, in community-dwelling elderly Japanese of a specific age. BACKGROUND: The relationship between alcohol consumption level and periodontitis is a controversial issue. METHODS: Participants were 438 dentate elders aged 73 years from a larger cohort survey of elders in Niigata City, Japan. Data collected from oral examination of each participant, including number of the existing teeth, mean probing pocket depth and mean clinical attachment level (CAL) were used for the analyses. A semiquantitative food frequency questionnaire and a lifestyle habit questionnaire were used to assess food and alcohol consumption, smoking experience, frequency of tooth brushing, interdental brush use, and visits to a dental clinic during the previous year. Blood glucose control was assessed by the glycated haemoglobin (HbA1c) level. Body mass index was calculated from height and weight measurements. The relationships between each variable and the individual mean CAL were analysed by univariate and multivariate analyses. RESULTS: According to logistic regression analysis, the mean CAL was significantly associated with the number of existing teeth (odds ratio [OR] = 0.90; P < .001), being a heavy drinker (OR = 2.44; P < .05), and smoking experience (OR = 2.37; P < .01). CONCLUSION: This study showed that increased mean CAL was significantly associated with heavy drinking in community-dwelling elderly Japanese (aged 73 years) compared with non-drinking. Our results provide new evidence that high alcohol consumption is associated with an increased risk of periodontal disease and its progression.

DOI： 10.1111/ger.12335

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

Objective: To develop and evaluate, with a dentist as gold standard, an oral health screening tool, the Oral Health Screening Tool for Nursing Personnel (OHSTNP), that assists long-term care facility nursing staff without preliminary training in identifying resident need for dentist referral. Methods: Using an OHSTNP adapted from previous screening tools (Chalmers, J Gerontol Nurs, 2004, 30, 5
Tsukada, J Jpn Soc Dent Hyg, 2012, 7, 43), one of four nurses, one of eight caregivers and a dentist with 15 years’ experience screened the oral health/function of 57 long-term care facility residents. The OHSTNP included a question on the need and reasons for dentist referral. Tool reliability and validity were evaluated by determining inter-rater agreement (Cohen's kappa), sensitivity, specificity and accuracy. Results: For dentist-nurse and dentist-caregiver pairs, kappa was statistically significant and sensitivity was high (≥0.67, nurses
≥0.71, caregivers) for natural teeth, dentures and oral function-related categories. Specificity for all categories was ≥0.69. Screening by nurses and caregivers for need for referral had low sensitivity (0.05, 0.23), accuracy (0.25, 0.39) and kappa (−0.01, 0.08). However, if nursing staff had been instructed to request a dentist referral in case of alterations in natural teeth/dentures or severe alterations in any other category, the estimated values increased to a sensitivity of 0.86 and 0.91, an accuracy of 0.75 and 0.82 and a kappa of 0.26 and 0.47. Conclusions: OHSTNP was reliable and valid for screening natural teeth, denture conditions and oral functions. Supplementary guidelines improved estimates of OHSTNP sensitivity, accuracy and reliability for nurse/caregiver assessment of resident need for dentist referral.

DOI： 10.1111/ger.12255

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

Objectives: (i) To assess comprehension of oral care-related terms among caregivers and nurses working at long-term care facilities, using a newly developed test
(ii) to analyse the effect of participant characteristics on their comprehension. Background: Effective mutual communication between dental professionals and caregivers/nurses is essential for providing information on daily oral care for institutionalised elders. Methods: A 36-item word-knowledge test in Japanese was developed to assess comprehension of oral care-related terms. The test was administered to a convenience sample of 236 nursing staff (198 caregivers and 38 nurses) at six long-term care facilities in Niigata City, Japan, and its reliability and validity were verified. Associations of participant characteristics with their responses were investigated by multiple regression analysis. Results: Mean percentage of correct responses (accuracy rate) for nursing staff was approximately 62% (highest for oral care products and lowest for prosthodontic terms). Test internal reliability was high (Cronbach's alpha &gt
0.8). Concurrent validity (test ability to distinguish between characteristically different groups) was confirmed. Mean accuracy rate was significantly higher among nurses (78.5 ± 19.3%) than among caregivers (58.7 ± 22.8%), and among respondents with interest in oral care (64.2 ± 21.1%) than among those with no such interest (51.5 ± 28.9%). Conclusion: The word-knowledge test was valid and reliable for nursing staff of six long-term care facilities in Niigata City. Their comprehension was low for perioral and intraoral structures, related symptom and disease names, and prosthodontics terms related to oral care. Understanding of oral care-related terms among the nursing staff was related to their occupation and interest in oral care.

DOI： 10.1111/ger.12223

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Bentham Science Publishers B.V.  

Background and Objective: Tube feeding has been significantly associated with a higher rate of aspiration pneumonia that is mainly related to oral microorganisms and a reduced salivary flow. Thus, the difference in the mode of nutritional intake is expected to affect the oral environment, but this has not yet been fully clarified. The purpose of this study was to investigate, in tube-fed patients, changes in the oral moisture and the counts of microorganisms in saliva and tongue coating, which occur after oral ingestion resumption. Methods: Study participants were 7 tube-fed inpatients of the Niigata University Medical and Dental Hospital (72.7±8.5 years old) who received dysphagia rehabilitation at the Unit of Dysphagia Rehabilitation until oral ingestion resumption. Their oral health, swallowing, and nutrition status, oral mucosal moisture, amount of unstimulated saliva and the counts of microorganisms (total microorganisms, streptococci, Candida) in saliva and tongue coating were investigated and compared before and after the recommencement of oral intake. Results: Tongue coating, choking, oral mucosal moisture and amount of unstimulated saliva were improved significantly after resumption of oral ingestion. The other investigated parameters did not significantly change, except for the streptococci in tongue coating, which significantly increased 1 week after oral ingestion recommencement, but decreased thereafter. Conclusion: After oral intake resumption, oral mucosal moisture and amount of unstimulated saliva were improved. However, because of a transitory increase in the counts of streptococci with oral ingestion recommencement, it is important to appropriately manage oral hygiene in these patients, according to the changes in their intraoral microbiota.

DOI： 10.2174/1874210601610010079

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：International Congress of Oral Implantologists  

DOI： 10.1097/ID.0000000000000369

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BIOMED CENTRAL LTD  

Background: Globalization of the professions has become a necessity among schools and universities across the world. It has affected the medical and dental professions in terms of curriculum design and student and patient needs. In Japan, where medicine and dentistry are taught mainly in the Japanese language, profession-based courses in English, known as Medical English and Dental English, have been integrated into the existing curriculum among its 83 medical and 29 dental schools. Unfortunately, there is neither a core curriculum nor a model syllabus for these courses.
Methods: This report is based on a survey, two discussion forums, a workshop, and finally, the drafting of a proposed core curriculum for dental English approved by consensus of the participants from each university.
Results: The core curriculum covers the theoretical aspects, including dental English terms and oral pathologies; and practical aspects, including blended learning and dentist-patient communication. It is divided into modules and is recommended to be offered for at least two semesters.
Conclusions: The core curriculum is expected to guide curriculum developers in schools where dental English courses are yet to be offered or are still in their early development. It may also serve as a model curriculum to medical and dental schools in countries in Asia, Europe, Africa, and Central and South America, where English is not the medium of instruction.

DOI： 10.1186/s12909-014-0239-4

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

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society for Dental Hygiene  

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Niigata Dental Society  

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Societatea Romana de Stomatologie  

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society for Dental Hygiene  

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Other Link： http://search.jamas.or.jp/link/ui/2012361933

Language：Japanese  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：日本歯科医学教育学会  

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japanese Dental Education Association  

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

Purpose: There are no entire maxillary finite element analysis models available, as a base of reference for the dimensions of conventional segment finite element analysis models. The objectives of this study were: (1) to construct a maxillary model derived from a human skull and to investigate the strain distribution around a posterior implant embedded in it; (2) to investigate the usability of conventional segment maxillary models.
Methods: CT DICOM data of a human dried skull maxilla was imported into the Mesh Generation Tools (ANSYS AI environment) and a computer-generated implant-abutment unit was bicortically embedded into it. In this Large model, Von Mises strains under axial and buccolingual loads were then calculated by a finite element program. Moreover, two simplified maxillary segments (Simplified models) were computer-generated and their Von Mises strains were similarly calculated.
Results: Although absolute values differed markedly, strain distribution patterns in the cortical bone were similar to those in the Simplified models: high Von Mises strains in the cortical bone concentrated in the sinus floor around the implant apex under axial load, and in the alveolar crest around the implant neck under buccolingual load.
Conclusions: The simplified and segmented three-dimensional finite element models of the human maxilla showed the same locations of the highest equivalent strains as the full maxilla model created from CT DICOM data. If absolute strain values are not of interest, the Simplified models could be used in strain analyses of simulated posterior maxilla for diagnostic suggestions in implant placement. (C) 2010 Japan Prosthodontic Society. Published by Elsevier Ireland. All rights reserved.

DOI： 10.1016/j.jpor.2010.07.002

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Societatea Romana de Stomatologie  

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

Purpose: There is no clear evidence of the factors that could improve implant biomechanics in the posterior maxilla. Thus, a finite element analysis was performed to investigate the effect of maxillary cortical bone thickness, implant design and diameter on stress around implants.
Methods: A total of 12 models of the posterior maxilla with implant were computer-simulated by varying the thickness of the alveolar cortical bone (1.5, 1.0, 0.5 or 0 mm) and implant characteristics (cylindrical implant of 4.1-mm diameter, screw-type implants of 4.1-mm or 4.8-mm outer diameters). On top of each implant, forces were separately applied axially (100 N) and buccolingually (50 N), and the von Mises stresses were calculated.
Results: Regardless of load direction, implant design and diameter, cortical and cancellous bone stresses increased with the decrease of crestal cortical bone thickness. In the absence of crestal cortical bone, cancellous bone stresses were highest and, under axial load, were transferred to the sinus floor. Implant design and diameter influenced stress to a less extent, especially under buccolingual load and in the presence of crestal cortical bone.
Conclusions: From a biomechanical viewpoint, to improve implant success odds in the posterior maxilla, rather than implant selection, careful preoperative evaluation of the cortical bone at the planned implant site is recommended. If this cortical bone is very thin or even lacking, implant treatment should be carried on with caution by progressive loading in the range of functional loads. (C) 2010 Japan Prosthodontic Society. Published by Elsevier Ireland. All rights reserved.

DOI： 10.1016/j.jpor.2009.12.004

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Language：Japanese   Publisher：新潟歯学会  

近年，口腔癌放射線治療で患者QOL を維持するために，口腔ケアの重要性が指摘されている。今回，舌部分切除術ならびに全頸部郭清術後の放射線治療患者に対し，放射線照射前から終了後まで継続して口腔ケアを実施し，患者QOL の変化を追った１例を経験した。本症例では，口内炎は10Gy 照射時より認められたものの，40Gy 照射時からは軽減し，治療期間を通して深い潰瘍形成や高度な疼痛はみられなかった。また，誤嚥性肺炎を発症することはなかった。さらに，「機能的な問題」「痛み」「不快感」「困りごと」の４領域，38 項目からなる口腔保健関連QOL 尺度を調査したところ，その低下も認められなかった。本症例の放射線治療において口腔ケアを行ったことは，患者QOL の観点から有用であったと考えられた。In recent years, the importance of oral health-related quality of life (QOL) in patients undergoing radiotherapy has been pointed out. The purposes of this study were to report on the implementation of oral care and to investigate its effect on the QOL of a patient undergoing radiotherapy, after partial glossotomy and neck dissection, over a time span that started before radiotherapy and ended at his release from hospital. In this case, radiation stomatitis was diagnosed when the patient received 10Gy radiation, but symptoms relieved when he received 40Gy radiation. In this case, aggravation ulcers and exacerbation of pain did not occur during therapy. Moreover, this patient did not develop aspiration pneumonia. Furthermore, during the study, oral health-related QOL as investigated by 38-items in the fields of &quot;Functional Problem&quot;, &quot;Pain&quot;, &quot;Uncomfortable Feeling&quot; and &quot;Difficulties&quot; did not show any deterioration. Therefore, the implementation of oral care in this radiotherapy patient is considered to be useful from the point of view of patient&#039;s oral health-related QOL.

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：QUINTESSENCE PUBLISHING CO INC  

Most 3-dimensional (3D) finite element analyses (FEAs) simplify the cancellous bone to a block and completely ignore its trabecular structure. Thus, a 3D FEA was performed to compare the peri-implant stress distribution of a model in which the trabecular structure was accurately simulated (precise model) with that of a model with a homogenous cancellous bone component (simplified model). In contrast to the simplified model, the distribution patterns and higher stresses in the precise model may explain the overall bone resorption at the implant-bone interface in load-related implant failures. Further studies using data from the jawbone and a more detailed implant simulation are planned.

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

Average marginal bone resorption of about 1 mm after the first year of functional loading, which is followed by an annual loss of approximately 0.1 mm, has been reported in stable implants. However, finite element analyses on bone stress around implants have been limited to analysing the bone stress in the absence of any bone resorption. Thus, a three-dimensional finite element analysis was performed to compare the bone stresses in a non-resorption model with those in four models with bone resorption of two depths (1.3 and 2.6 mm) and types (horizontal resorption and angular defects). Axial and bucco-lingual forces were separately applied to the center of the superstructure and the maximum equivalent stress was calculated. The main tendencies of bone stress (highest stress concentration around implant neck, higher stresses under bucco-lingual than axial load, as well as in the cortical than cancellous bone) were the same in the non-resorption and resorption models. Bone stress distributions were similar in the non-resorption and horizontal resorption models, but differed from those in the angular defect models. Moreover, the changes of the bone stress values with resorption depth differed for the two resorption types. Thus, in FEA, accurate simulation of the marginal bone shape in the implant neck region is advisable.

DOI： 10.1111/j.1365-2842.2004.01413.x

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

Purpose: This investigation was concerned with the effect of 3 superstructure materials on the strain around an implant under static and nonimpact dynamic loading. Materials and Methods: Five highly filled composite resin-veneered crown analogs, 5 autopolymerized acrylic resin-veneered crown analogs, and 5 gold-alloy full cast crown analogs were prepared. The resin veneers were applied to gold-alloy frameworks. These crown analogs were prepared to fit an ITI implant-abutment assembly, which was screwed into a block of acrylic resin to simulate implantation in bone. The crown analogs were successively placed on the abutment, and a lateral load of 100 N was applied to the superstructure by a lever-type testing machine. Strains were recorded under static and dynamic loading by a 2-mm-long strain gauge bonded to the surface of the bone simulant tangential to the implant. The dynamic load simulated masticatory cycles (75 strokes/min). Results: Although the strain values differed significantly between the static and dynamic loading (P &lt; .05), there was no significant difference among the superstructure materials under either loading condition (P &gt; .05). Discussion: These findings are in agreement with in vivo measurements, thus suggesting that cyclic rather than impact loading should be used in the investigation of occlusal material behavior under functional loading. Conclusion: Under static and nonimpact dynamic loading, the 3 superstructure materials tested (highly filled composite resin, acrylic resin, and gold alloy) had the same influence on the strain transmitted to a bone simulant that surrounded a single implant.

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

Objectives: Although bone loss around implants is reported as a complication when it progresses uncontrolled, resorption does not always lead to implant loss, but may be the result of biomechanical adaptation to stress. To verify this hypothesis, a three-dimensional finite element analysis was performed and the influence of marginal bone resorption amount and shape on stress in the bone and implant was investigated.
Material and methods: A total of nine bone models with an implant were created: a non-resorption (Base) model and eight variations, in which three different resorption depths were combined with pure vertical or conical (vertical-horizontal) resorption. Axial and buccolingual forces were applied independently to the occlusal node at the center of the superstructure.
Results: Regardless of load direction, bone stresses were higher in the pure vertical resorption (A) models than in the Base model, and increased with resorption depth. However, cortical bone stress was much lower in the conical resorption models than in both the Base and A models of the same resorption depth. An opposite tendency was observed in the cancellous bone under buccolingual load. Under buccolingual load, highest stress in the implant increased linearly with the resorption depth for all the models and its location approached the void existing below the abutment screw.
Conclusions: The results of this analysis suggest that a certain amount of conical resorption may be the result of biomechanical adaptation of bone to stress. However, as bone resorption progresses, the increasing stresses in the cancellous bone and implant under lateral load may result in implant failure.

DOI： 10.1111/j.1600-0501.2004.01022.x

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

Purpose: A 3-dimensional finite element analysis was performed to evaluate the influence of implant type and length, as well as that of bone quality, on the stress/strain in bone and implant. Materials and Methods: Two types (screw and cylinder) and 4 lengths (9.2, 10.87 12.4, and 14.0 mm) of titanium implants were buried in 4 types of bone modeled by varying the elastic modulus for cancellous bone. Axial and buccolingual forces were applied to the occlusal node at the center of the abutment. Results: Regardless of load direction, maximum equivalent stress/strain in bone increased with a decrease in cancellous bone density. Under axial load, especially in the low-density bone models, maximum equivalent strain in cancellous bone was lower with the screw-type implant than with the cylinder-type implant. It was also lower with the longer implants than with the shorter implants. Under buccolingual load, equivalent stress/strain was influenced mainly by bone density. Discussion: This study confirms the importance of bone quality and its presurgical diagnosis for implant long-term prognosis, Implant length and type can also influence bone strain, especially in low-density bone. Conclusions: The results of this study suggest that cancellous bone of higher rather than lower density might ensure a better biomechanical environment for implants. Moreover, longer screw-type implants could be a better choice in a jaw with cancellous bone of low density.

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

Statement of problem. Because of reported mechanical failures, alternative implant system components with suggested optimized strength have been manufactured. However, the endurance of these products has not been well investigated.
Purpose. This study was designed to assess the effect of joint design on the fatigue strength and failure mode of 2 single-tooth implant systems: Br (a) over circle nemark and ITI, in which a hex mediated-butt joint and 8-degree internal conical implant/abutment interface are used, respectively.
Material and methods. Seven 10-mm implants from each implant system mere embedded to a depth of 7 mm in cylindrical acrylic resin blocks. CeraOne and Solid abutments with cement-retained castings were assembled to the Br (a) over circle nemark and ITI implants, respectively. The assembled units were mounted in a lever-type-testing machine that was equipped with an automatic counting device and shutoff sensors, enabling the recording of the number of cycles till failure. A cyclic load of 100 N was applied perpendicular to the long axis of the assemblies at a rate of 75 cycles/min. To investigate specimen resistance to fatigue during 6 years of simulated function, a target of 1,800,000 cycles was defined. Specimen preparation and testing was performed by the same operator. The association of the joint design with the occurrence of failure was verified by Fisher's exact probability test (P&lt;.05).
Results. For the Br (a) over circle nemark group, the gold alloy abutment screw in all specimens fractured between 1,178,023 and 1,733,526 cycles with a standard deviation of 224,477 cycles. For the ITI group, all specimens had no failure until 1,800,000 cycles. Statistical analysis showed a highly significant difference between the 2 groups (P=.000582).
Conclusion. Within the limitations of this in vitro study, the effect of joint design on the fatigue strength and failure mode of the ITI single tooth implant system was significantly better (P&gt;.001) than the Br (a) over circle nemark single-tooth implant system tested.

DOI： 10.1067/mpr.2002.129384

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Niigata University  

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Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Niigata University  

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

A 3-dimensional finite element analysis was conducted to assess stress distribution in bone, implant, and abutment when gold alloy, porcelain, or resin (acrylic or composite) was used for a 3-unit prosthesis. A unit force was applied axially and then buccolingually to the center of the pontic. For gold and porcelain, similar maximum equivalent stress was found in each part of the models. In almost all cases, stress in the model with the resin prostheses was similar to or higher than that in the models with the other 2 prosthesis materials. The highest increase in stress with the resins was found in the implant-abutment unit under axial load. The protective role of resin for the implant-bone interface could not be demonstrated under the conditions of this analysis. (INT J Oral Maxillofac Implants 1998;13:781-790).

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

The three-dimensional finite element analysis method was used to assess stress in bone around titanium implants using three treatment designs for a partially edentulous mandible, under axial (AX), buccolingual (BL), or mesiodistal (MD) loads. For each of these loads, highest stress was calculated in the model with a cantilever prosthesis supported by two implants (M2). Less stress was found in the model with a conventional fixed partial denture on two implants (M3), and lowest stress was calculated in the model with three connected crowns supported by three implants (M1). When BL load was applied to M3, cortical bone stress was high, comparable to that calculated for M2 under the same load. When AX or MD load was applied to M3, the cortical bone stress was low,similar to that found in M1 under each of these loads.

Web of Science

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：MOSBY-YEAR BOOK INC  

Retention of a prefabricated post and composite resin core system was compared with that of a cast post and core restoration in anterior maxillary teeth on which root canal preparations, enlarged in the coronal part, were performed. The effect of cyclic loading on restoration retention was also investigated. Retention of restorations not subjected to cyclic loading was not influenced by post type, but loaded prefabricated post restorations showed lower retention than both loaded cast post and core restorations and nonloaded prefabricated post restorations. After dislodgment, the failure mode was also determined. The results of this study suggest that if a canal requires extensive preparation, a web-adapted cast post and core restoration may be more retentive than a prefabricated post restoration that does not match the canal shape.

Web of Science

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Publishing type：Research paper, summary (international conference)  

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Authorship：Lead author   Publishing type：Research paper, summary (international conference)  

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Publishing type：Research paper, summary (national, other academic conference)  

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Authorship：Lead author   Publishing type：Research paper, summary (national, other academic conference)  

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Language：Japanese  

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Language：Japanese  

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

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

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Authorship：Lead author   Language：English   Publishing type：Research paper, summary (international conference)  

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

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Language：Japanese  

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Language：Japanese  

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Authorship：Lead author   Language：English   Publishing type：Research paper, summary (international conference)  

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Authorship：Lead author   Language：Romanian, Moldavian, Moldovan  

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Authorship：Lead author   Language：English   Publishing type：Research paper, summary (international conference)  

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Authorship：Lead author   Language：Japanese  

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Language：Japanese  

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

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

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Authorship：Corresponding author   Language：English   Publishing type：Research paper, summary (international conference)  

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Language：Japanese  

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Language：Japanese   Publishing type：Meeting report   Publisher：日本歯科衛生学会  

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Language：Japanese  

J-GLOBAL

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Language：Japanese   Publishing type：Meeting report   Publisher：日本歯科衛生学会  

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Language：Japanese  

J-GLOBAL

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Language：Japanese  

CiNii Article

CiNii Books

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Language：Japanese  

J-GLOBAL

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Language：Japanese  

J-GLOBAL

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Language：Romanian, Moldavian, Moldovan  

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Language：Japanese   Publisher：新潟歯学会  

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Language：Japanese  

J-GLOBAL

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Language：Japanese  

J-GLOBAL

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Language：Japanese  

CiNii Article

CiNii Books

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Event date： 2023.10

Language：Romanian, Moldavian, Moldovan  

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Event date： 2023.9

Presentation type：Oral presentation (general)  

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Event date： 2022.11

Language：Romanian, Moldavian, Moldovan   Presentation type：Oral presentation (invited, special)  

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Event date： 2022.10

Presentation type：Poster presentation  

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Event date： 2022.7

Language：Japanese   Presentation type：Poster presentation  

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Event date： 2021.11 - 2021.12

Language：Japanese   Presentation type：Poster presentation  

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Event date： 2021.11

Language：English  

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Event date： 2021.9

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2021.9

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2021.7

Language：English   Presentation type：Poster presentation  

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Event date： 2019.6

Language：English   Presentation type：Oral presentation (invited, special)  

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Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Poster presentation  

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Language：Romanian, Moldavian, Moldovan   Presentation type：Oral presentation (invited, special)  

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Language：English   Presentation type：Oral presentation (invited, special)  

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Language：Romanian, Moldavian, Moldovan   Presentation type：Oral presentation (invited, special)  

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Language：English   Presentation type：Oral presentation (invited, special)  

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Language：English   Presentation type：Poster presentation  

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Presentation type：Symposium, workshop panel (nominated)  

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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Language：Romanian, Moldavian, Moldovan   Presentation type：Oral presentation (invited, special)  

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