Language：Japanese   Publisher：(NPO)日本歯科保存学会  

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

Hydroxyapatite formation on endodontic hydraulic calcium silicate cements (HCSCs) plays a significant role in sealing the root canal system and elevating the hard-tissue inductivity of the materials. This study evaluated the in vivo apatite-forming ability of 13 new-generation HCSCs using an original HCSC (white ProRoot MTA: PR) as a positive control. The HCSCs were loaded into polytetrafluoroethylene tubes and implanted in the subcutaneous tissue of 4-week-old male Wistar rats. At 28 days after implantation, hydroxyapatite formation on the HCSC implants was assessed with micro-Raman spectroscopy, surface ultrastructural and elemental characterization, and elemental mapping of the material-tissue interface. Seven new-generation HCSCs and PR had a Raman band for hydroxyapatite (v1 PO43- band at 960 cm-1) and hydroxyapatite-like calcium-phosphorus-rich spherical precipitates on the surfaces. The other six HCSCs with neither the hydroxyapatite Raman band nor hydroxyapatite-like spherical precipitates did not show calcium-phosphorus-rich hydroxyapatite-layer-like regions in the elemental mapping. These results indicated that 6 of the 13 new-generation HCSCs possessed little or no ability to produce hydroxyapatite in vivo, unlike PR. The weak in vivo apatite-forming ability of the six HCSCs may have a negative impact on their clinical performance.

DOI： 10.3390/jfb14040213

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Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.jbc.2023.104760

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

Calcium salt precipitation induced by intracanal medicaments contributes to the formation of apical hard tissue during apexification. This study compared the calcium salt-forming ability of a new calcium silicate-based intracanal medicament (Bio-C Temp) with that of two commercial calcium hydroxide pastes (Calcipex Plane II and Vitapex) in a rat subcutaneous implantation model. Polytetrafluoroethylene tubes containing each of the three materials were subcutaneously implanted in 4-week-old male Wistar rats. After 28 days, the composition and amount of calcium salts formed at the material-tissue interface were assessed using micro-Raman spectroscopy, X-ray diffraction, and elemental mapping. The tested materials produced white precipitates that had Raman spectra with peaks corresponding to hydroxyapatite and calcite. X-ray diffraction detected hydroxyapatite formation on Calcipex Plane II and Vitapex implants, as well as calcite formation on all three materials. Elemental mapping revealed that Bio-C Temp generated significantly smaller calcium- and phosphorus-rich calcified regions within the subcutaneous connective tissue than Vitapex. These results indicate that Bio-C Temp produced less calcium salt in rat subcutaneous tissue than Vitapex, although all materials formed hydroxyapatite and calcite in rat subcutaneous tissue. Bio-C Temp could be less effective than Vitapex in promoting apical hard tissue formation during apexification.

DOI： 10.3390/dj11040091

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

INTRODUCTION: Prostaglandin E2 (PGE2) exerts biological actions through its transport pathway involving intracellular synthesis, extracellular transport, and receptor binding. This study aimed to determine the localization of the components of the PGE2-transporting pathway in human dental pulp and explore the relevance of PGE2 receptors (EP2/EP4) to angiogenesis and dentinogenesis. METHODS: Protein localization of microsomal PGE2 synthase (mPGES), PGE2 transporters [(multidrug resistance-associated protein-4 (MRP4) and prostaglandin transporter (PGT)], and EP2/EP4 was analyzed using double immunofluorescence staining. Tooth slices from human third molars were cultured with or without butaprost (EP2 agonist) or rivenprost (EP4 agonist) for 1 week. Morphometric analysis of endothelial cell filopodia was performed to evaluate angiogenesis, and real-time polymerase chain reaction was performed to evaluate angiogenesis and odontoblast differentiation markers. RESULTS: MRP4 and PGT were colocalized with mPGES and EP2/EP4 in odontoblasts and endothelial cells. Furthermore, MRP4 was colocalized with mPGES and EP4 in human leukocyte antigen-DR-expressing dendritic cells. In the tooth slice culture, EP2/EP4 agonists induced significant increases in the number and length of filopodia and mRNA expression of angiogenesis markers (vascular endothelial growth factor and fibroblast growth factor-2) and odontoblast differentiation markers (dentin sialophosphoprotein and collagen type 1). CONCLUSIONS: PGE2-producing enzyme (mPGES), transporters (MRP4 and PGT), and PGE2-specific receptors (EP2/EP4) were immunolocalized in various cellular components of the human dental pulp. EP2/EP4 agonists promoted endothelial cell filopodia generation and upregulated angiogenesis- and odontoblast differentiation-related genes, suggesting that PGE2 binding to EP2/EP4 is associated with angiogenic and dentinogenic responses.

DOI： 10.1016/j.joen.2023.01.009

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Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

The oral cavity is the second most colonized site of Helicobacter pylori after the stomach. This study aimed to compare the genetic relatedness between gastric and oral H. pylori in Japanese patients with early gastric cancer through multilocus sequence typing (MLST) analysis using eight housekeeping genes. Gastric biopsy specimens and oral samples were collected from 21 patients with a fecal antigen test positive for H. pylori. The number of H. pylori allelic profiles ranged from zero to eight since the yield of DNA was small even when the nested PCR was performed. MLST analysis revealed that only one patient had a matching oral and gastric H. pylori genotype, suggesting that different genotypes of H. pylori inhabit the oral cavity and gastric mucosa. The phylogenetic analysis showed that oral H. pylori in six patients was similar to gastric H. pylori, implying that the two strains are related but not of the same origin, and those strains may be infected on separate occasions. It is necessary to establish a culture method for oral H. pylori to elucidate whether the oral cavity acts as the source of gastric infection, as our analysis was based on a limited number of allele sequences.

DOI： 10.3390/ijms24032211

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

Ascorbic acid (AA; vitamin C) plays a crucial role in the biosynthesis and secretion of collagen to produce the organic matrix of hard tissues. Nevertheless, the detailed mechanism by which AA induces reparative dentinogenesis is still unknown. This study aimed to investigate the pathway and function of AA during wound healing in a rat pulpotomy model. Sodium-dependent vitamin C transporter (SVCT) 2 and glucose transporter (GLUT) 1 were detected in odontoblasts, endothelial cells, and nerve fibers in normal pulp tissues. SVCT2 and GLUT1 were also expressed in odontoblast-like cells in pulpotomized tissues of Wistar rats, and immunopositive cells of SVCT2 were significantly increased at 5 days after pulpotomy (p < 0.05). By contrast, osteogenic disorder Shionogi (ODS) rats, which cannot generate AA, also expressed SVCT2 and GLUT1 in normal and wound healing conditions. However, in ODS rats, when compared with the AA-addition group, the formation of dentin bridges in the AA-loss group was not evident, a layer of osteopontin was significantly increased beneath the wound surface (p < 0.05), and alpha smooth muscle actin at the odontoblast-like cells observed along this layer was significantly increased (p < 0.05), but not Nestin. Moreover, the amounts of type 1 collagen generated in the reparative dentin and beneath the wound healing site were significantly diminished (p < 0.05). Macrophages expressing CD68 and CD206 increased beneath the wound site. Hence, AA may be involved in odontoblast-like cell differentiation and anti-inflammatory response during dental pulp wound healing. Our results provide new insights into the function of AA through SVCT2 and GLUT1 in reparative dentinogenesis and may help in developing new therapeutic targets for dental pulpal disease.

DOI： 10.1038/s41598-023-28197-9

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

The coronavirus disease pandemic has afforded dental professionals an opportunity to reconsider infection control during treatment. We investigated the efficacy of combining extraoral high-volume evacuators (eHVEs) with preprocedural mouth rinsing in reducing aerosol contamination by ultrasonic scalers. A double-masked, two-group, crossover randomized clinical trial was conducted over eight weeks. A total of 10 healthy subjects were divided into two groups; they received 0.5% povidone-iodine (PI), essential oil (EO), or water as preprocedural rinse. Aerosols produced during ultrasonic scaling were collected from the chest area (PC), dentist's mask, dentist's chest area (DC), bracket table, and assistant's area. Bacterial contamination was assessed using colony counting and adenosine triphosphate assays. With the eHVE 10 cm away from the mouth, bacterial contamination by aerosols was negligible. With the eHVE 20 cm away, more dental aerosols containing bacteria were detected at the DC and PC. Mouth rinsing decreased viable bacterial count by 31-38% (PI) and 22-33% (EO), compared with no rinsing. The eHVE prevents bacterial contamination when close to the patient's mouth. Preprocedural mouth rinsing can reduce bacterial contamination where the eHVE is positioned away from the mouth, depending on the procedure. Combining an eHVE with preprocedural mouth rinsing can reduce bacterial contamination in dental offices.

DOI： 10.3390/ijerph19106048

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

OBJECTIVE: Bioceramic-containing root canal sealers promote periapical healing via Ca2+ and OH- release and apatite formation on the surface. This study aimed to compare Ca2+ and OH- release and in vivo apatite formation of three bioceramic-containing root canal sealers: EndoSequence BC sealer (Endo-BC), MTA Fillapex (MTA-F), and Nishika Canal Sealer BG (N-BG). MATERIALS AND METHODS: Polytetrafluoroethylene tubes filled with sealers were immersed in distilled water for 6 and 12 h and for 1, 7, 14, and 28 days to measure Ca2+ and OH- release. Additionally, tubes filled with sealers were implanted in the backs of rats for 28 days, and in vivo apatite formation was analyzed using an electron probe microanalyzer. RESULTS: Endo-BC released significantly more Ca2+ than the other sealers at 6 and 12 h and 1 day. Ca2+ release was significantly lower from N-BG than from Endo-BC and MTA-F at 14 and 28 days. OH- release was significantly higher from Endo-BC than from the other sealers throughout the experiment, except at 1 day. OH- release was lower from N-BG than from MTA-F at 6 h and 7 days. Only Endo-BC implants exhibited apatite-like calcium-, phosphorus-, oxygen-, and carbon-rich spherulites and apatite layer-like calcium- and phosphorus-rich, but radiopaque element-free, surface regions. CONCLUSIONS: Ca2+ and OH- release is ranked as follows: Endo-BC > MTA-F > N-BG. Only Endo-BC demonstrated in vivo apatite formation. CLINICAL RELEVANCE: Endo-BC could promote faster periapical healing than MTA-F and N-BG.

DOI： 10.1007/s00784-021-04118-w

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Other Link： https://link.springer.com/article/10.1007/s00784-021-04118-w/fulltext.html

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

Antimicrobial mouthwash improves supragingival biofilm control when used in conjunction with mechanical removal as part of an oral hygiene routine. Mouthwash is intended to suppress bacterial adhesion during biofilm formation processes and is not aimed at mature biofilms. The most common evidence-based effects of mouthwash on the subgingival biofilm include the inhibition of biofilm accumulation and its anti-gingivitis property, followed by its cariostatic activities. There has been no significant change in the strength of the evidence over the last decade. A strategy for biofilm control that relies on the elimination of bacteria may cause a variety of side effects. The exposure of mature oral biofilms to mouthwash is associated with several possible adverse reactions, such as the emergence of resistant strains, the effects of the residual structure, enhanced pathogenicity following retarded penetration, and ecological changes to the microbiota. These concerns require further elucidation. This review aims to reconfirm the intended effects of mouthwash on oral biofilm control by summarizing systematic reviews from the last decade and to discuss the limitations of mouthwash and potential adverse reactions to its use. In the future, the strategy for oral biofilm control may shift to reducing the biofilm by detaching it or modulating its quality, rather than eliminating it, to preserve the benefits of the normal resident oral microflora.

DOI： 10.3390/antibiotics1106072719106048

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

We performed a comprehensive microbiome analysis of root caries lesions using 22 teeth extracted from patients with severe periodontitis. The carious lesions were mechanically collected and cryo-pulverized following tooth extraction. Differences in the microbiome were compared between independent lesions at the supragingival site (SG) and lesions extending beyond the gingival margin (GCB). DNA was extracted and the microbiome was characterized on the basis of the V3-V4 hypervariable region of the 16S rRNA gene using paired-end sequencing on an Illumina MiSeq device. The microbiota in root caries lesions showed compositionally distinct microbiota depending on the location. The most abundant OTUs in the SG group were Streptococcus (26.0%), Actinomyces (10.6%), and Prevotella (7.6%). GCB presented Prevotella (11.1%) as the most abundant genus, followed by Fusobacterium (9.6%) and Actinomyces (8.7%). The SG group showed a lack of uniformity in microbiota compared with the GCB group. The bacterial profiles of GCB varied considerably among patients, including periodontal pathogens such as Porphyromonas, Selenomonas, Filifactor, Peptococcus, and Tannerella. Periodontal pathogens inhabit root caries lesions that extend beyond the gingival margin. This study provides a new perspective for elucidating the microbial etiology of root caries.

DOI： 10.3390/microorganisms9112349

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

Resin monomers and polymerisation initiators have been shown to be cytotoxic for pulp cells and to disturb odontoblast differentiation. This study aimed to compare the effect of a resin-modified calcium silicate cement (TheraCal LC; TC) and a resin-free calcium silicate cement (ProRoot MTA; PR) on pulpal healing after pulpotomy. Pulpotomy was performed on the maxillary first molars of 8-week-old rats using either PR or TC. After 1, 3, 7, 14 and 28 days, pulpal responses were assessed by micro-computed tomography, haematoxylin-eosin staining and immunostaining against CD68, which is a pan-macrophage marker. The results showed that pulpotomy with TC induced persistent infiltration of inflammatory cells, including CD68-positive macrophages, and delayed the formation of reparative dentin as compared with that with PR, although both materials allowed pulpal healing over the long term. Therefore, resin-modified TC was not as biocompatible nor bioinductive as resin-free PR when applied on the healthy pulp of rat molars.

DOI： 10.1111/aej.12568

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Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

This study compared the apatite-forming ability (AFA) levels of flowable and putty formulations of Nishika Canal Sealer BG Multi (F-NBG and P-NBG, respectively) and attempted to clarify the cause of differences in the AFA levels of F-NBG and P-NBG. NBG samples were aged in simulated body fluid (SBF) or 1-, 5-, or 10-g/L bovine serum albumin-containing SBF (BSA-SBF) and analyzed in terms of their ultrastructures, elemental compositions, and Raman spectra to identify apatite formation. The phosphate ion consumption rates of NBG samples in the media were evaluated as an indicator of apatite growth. The original elemental composition, calcium ion release, and alkalizing ability levels of F-NBG and P-NBG were also evaluated. Apparent apatite formation was detected on all NBG samples except F-NBG aged in 10-g/L BSA-SBF. P-NBG consumed phosphate ions faster than F-NBG. As-prepared P-NBG showed more silicon elements on its surface than as-prepared F-NBG. P-NBG released more calcium ions than F-NBG, although their alkalizing ability levels did not differ statistically. In conclusion, the AFA of P-NBG was greater than that of F-NBG, probably because of the greater ability of P-NBG to expose silanol groups on the surface and release calcium ions.

DOI： 10.3390/app11198969

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

This study aimed to evaluate the anticariogenic biofilm activity of a novel zinc-containing glass ionomer cement, Caredyne Restore (CR), using a flow-cell system that reproduces Stephan responses. Streptococcus mutans biofilms were cultured on either CR or hydroxyapatite (HA) discs mounted on a modified Robbins device. The media were allowed to flow at a speed of 2 mL/min for 24 h while exposed to an acidic buffer twice for 30 min to mimic dietary uptake. Acid exposure enhanced biofilm inhibition in the CR group, which showed 2.6 log CFU/mm2 in viable cells and a 2 log copies/mL reduction in total cells compared to the untreated group after 24 h of incubation, suggesting enhanced anticariogenic activity due to the release of fluoride and zinc ions. However, there was no difference in the number of viable and total cells between the two experimental groups after 24 h of incubation in the absence of an acidic environment. The anticariogenic biofilm activity of CR occurs in acidic oral environments, for example in the transient pH drop following dietary uptake. CR restorations are recommended in patients at high risk of caries due to hyposalivation, difficulty brushing, and frequent sugar intake.

DOI： 10.3390/antibiotics10080977

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

In Japan, gastric Helicobacter pylori infection prevalence has markedly decreased with socioeconomic development. We aimed to investigate the prevalence of oral H. pylori in Japanese adults in 2020 by sex, age, sampling site, and medical history. Unstimulated saliva, supragingival biofilm, and tongue coating were obtained from 88 subjects-with no complaints of upper digestive symptoms-attending a dentist's office for dental check-up or disorders. Supragingival biofilm was collected from the upper incisors, lower incisors, upper right molars and lower left molars to analyze the characteristic distribution. Oral H. pylori was detected using nested polymerase chain reaction. Oral H. pylori prevalence did not statistically differ by sex or age. Supragingival biofilm (30.7%) was the most common oral H. pylori niche; it was also detected in 4.5% of saliva and 2.3% of tongue samples. The lower incisor was the most common site among the supragingival biofilm samples, followed by the upper incisors, lower left molars, and upper right molars. Oral H. pylori DNA was frequently detected in patients with a history of gastric H. pylori infection. Oral H. pylori has a characteristic distribution independent of sex and age, suggesting that it is part of the normal microflora in the adult oral cavity.

DOI： 10.3390/pathogens10010010

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

BACKGROUND: Sulfated vizantin, a recently developed immunostimulant, has also been found to exert antibiofilm properties. It acts not as a bactericide, but as a detachment-promoting agent by reducing the biofilm structural stability. This study aimed to investigate the mechanism underlying this activity and its species specificity using two distinct ex vivo oral biofilm models derived from human saliva. RESULTS: The biofilm, composed mainly of the genus Streptococcus and containing 50 μM of sulfated vizantin, detached significantly from its basal surface with rotation at 500 rpm for only 15 s, even when 0.2% sucrose was supplied. Expression analyses for genes associated with biofilm formation and bacterial adhesion following identification of the Streptococcus species, revealed that a variety of Streptococcus species in a cariogenic biofilm showed downregulation of genes encoding glucosyltransferases involved in the biosynthesis of water-soluble glucan. The expression of some genes encoding surface proteins was also downregulated. Of the two quorum sensing systems involved in the genus Streptococcus, the expression of luxS in three species, Streptococcus oralis, Streptococcus gordonii, and Streptococcus mutans, was significantly downregulated in the presence of 50 μM sulfated vizantin. Biofilm detachment may be facilitated by the reduced structural stability due to these modulations. As a non-specific reaction, 50 μM sulfated vizantin decreased cell surface hydrophobicity by binding to the cell surface, resulting in reduced bacterial adherence. CONCLUSION: Sulfated vizantin may be a candidate for a new antibiofilm strategy targeting the biofilm matrix while preserving the resident microflora.

DOI： 10.1186/s12866-020-02033-w

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A previous study has reported that a novel fluoro-zinc-silicate glass ionomer cement (Caredyne Restore) showed superior anti-biofilm effects by interfering with bacterial adhesion. However, the active ions may degrade with time. This study aimed to assess the valid anti-biofilm effects of Caredyne Restore after being aged by water immersion for 3 weeks. Streptococcus mutans biofilm was allowed to grow on the surface before and after water aging for 24 h using a modified Robbins device flow-cell system. The results showed water aging promoted biofilm formation. Insufficient amount of fluoride and zinc ions were released from Caredyne Restore after water aging under neutral pH condition. An acidic pH is needed to exert effective anti-biofilm properties. As the release of active ions from Caredyne Restore will gradually decrease after the restoration,  the restoration may not prevent biofilm formation after 3 weeks while neutral pH is maintained by the buffering capacity of saliva.

DOI： 10.1080/08927014.2020.1856371

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Streptococcus mutans is the main pathogen of dental caries and adheres to the tooth surface via soluble and insoluble glucans produced by the bacterial glucosyltransferase enzyme. Thus, the S. mutans glucosyltransferase is an important virulence factor for this cariogenic bacterium. Sulfated vizantin effectively inhibits biofilm formation by S. mutans without affecting its growth. In this study, less S. mutans biofilm formation occurred on hydroxyapatite discs coated with sulfated vizantin than on noncoated discs. Sulfated vizantin showed no cytotoxicity against the human gingival cell line Ca9-22. Sulfated vizantin dose-dependently inhibited the extracellular release of cell-free glucosyltransferase from S. mutans and enhanced the accumulation of cell-associated glucosyltransferase, compared with that observed with untreated bacteria. Sulfated vizantin disrupted the localization balance between cell-associated glucosyltransferase and cell-free glucosyltransferase, resulting in inhibited biofilm maturation. These results indicate that sulfated vizantin can potentially serve as a novel agent for preventing dental caries.

DOI： 10.1111/1348-0421.12797

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BACKGROUND: The aim of this in vitro study was to examine the possible enhancement of the biofilm peeling effect of a sonic toothbrush following the use of an antimicrobial mouth rinse. METHODS: The biofilm at a noncontact site in the interdental area was treated by sound wave convection with the test solution or by immersion in the solution. The biofilm peeling effect was evaluated by determining the bacterial counts and performing morphological observations. A Streptococcus mutans biofilm was allowed to develop on composite resin discs by cultivation with stirring at 50 rpm for 72 h. The specimens were then placed in recesses located between plastic teeth and divided into an immersion group and a combination group. The immersion group was treated with phosphate buffer, chlorhexidine digluconate Peridex™ (CHX) mouth rinse or Listerine® Fresh Mint (EO) mouth rinse. The combination group was treated with CHX or EO and a sonic toothbrush. RESULTS: The biofilm thickness was reduced by approximately one-half compared with the control group. The combination treatment produced a 1 log reduction in the number of bacteria compared to the EO immersion treatment. No significant difference was observed in the biofilm peeling effect of the immersion group compared to the control group. CONCLUSIONS: The combined use of a sonic toothbrush and a mouth rinse enhanced the peeling of the biofilm that proliferates in places that are difficult to reach using mechanical stress.

DOI： 10.1186/s12903-020-01144-0

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Following antimicrobial administrations in oral environments, bacteria become exposed to a sub-minimum inhibitory concentration (sub-MIC), which can induce in vitro single-species biofilms. This study explored the effects of chlorhexidine gluconate (CHG) at a sub-MIC on in vitro multi-species biofilms comprising Streptococcus mutans, Streptococcus oralis and Actinomyces naeslundii. CHG at a sub-MIC was found to induce in vitro biofilm growth, although the bacterial growth was not significantly different from that in the control. The gene transcription related to S. mutans multi-species biofilm formation with CHG at a sub-MIC was significantly higher than that of the control, but this was not found in S. mutans single-species biofilms. The bio-volume of extracellular polysaccharides with CHG at a sub-MIC was significantly higher than that of the control. This suggests that CHG at a sub-MIC may promote the development of multi-species biofilms by affecting the gene transcription related to S. mutans biofilm formation.

DOI： 10.1080/08927014.2020.1739271

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

Objectives This study is aimed at evaluating the effect of a new glass ionomer cement (GIC) containing fluoro-zinc-silicate fillers on biofilm formation and ion incorporation. Materials and methods Streptococcus mutans biofilms were developed on two GIC materials: Caredyne Restore (CD) and Fuji VII (FJ); and hydroxyapatite (HA) for 24 h at 37 degrees C using a flow cell system. The morphological structure and bacterial viability were analyzed using a confocal laser scanning microscopy. Bacterial adhesion during the initial 2 h was also assessed by viable cell counting. To study the ion incorporation, restored cavities prepared on the root surfaces of human incisors were subjected to the elemental mapping of the zinc and fluoride ions in the GIC-dentin interface using a wavelength-dispersive X-ray spectroscopy electron probe microanalyzer. Results Morphological observations revealed that biofilm formation in the CD group was remarkably inhibited compared with the HA and FJ groups, exhibiting sparse, thinner biofilm clusters. The microorganisms adhering to the CD group were significantly inhibited, revealing 2.9 +/- 0.4 for CD, 4.9 +/- 0.2 for FJ, and 5.4 +/- 0.4 log colony-forming units (CFU) for HA. The CD zinc ion incorporation depth was 72.2 +/- 8.0 mu m. The fluoride penetration of CD was three times deeper than that of FJ; this difference was statistically significant (p < 0.05). Conclusions Enhanced by the incorporation of zinc and fluoride ions, the new GIC inhibited biofilm formation by interfering with bacterial adhesion.

DOI： 10.1007/s00784-019-02991-0

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Streptococcus pneumoniae is often isolated from patients with community-acquired pneumonia. Antibiotics are the primary line of treatment for pneumococcal pneumonia; however, rising antimicrobial resistance is becoming more prevalent. Hinokitiol, which is isolated from trees in the cypress family, has been demonstrated to exert antibacterial activity against S. pneumoniae in vitro regardless of antimicrobial resistance. In this study, the efficacy of hinokitiol was investigated in a mouse pneumonia model. Male 8-week-old BALB/c mice were intratracheally infected with S. pneumoniae strains D39 (antimicrobial susceptible) and NU4471 (macrolide resistant). After 1 h, hinokitiol was injected via the tracheal route. Hinokitiol significantly decreased the number of S. pneumoniae in the bronchoalveolar lavage fluid (BALF) and the concentration of pneumococcal DNA in the serum, regardless of whether bacteria were resistant or susceptible to macrolides. In addition, hinokitiol decreased the infiltration of neutrophils in the lungs, as well as the concentration of inflammatory cytokines in the BALF and serum. Repeated hinokitiol injection at 18 h intervals showed downward trend in the number of S. pneumoniae in the BALF and the concentration of S. pneumoniae DNA in the serum with the number of hinokitiol administrations. These findings suggest that hinokitiol reduced bacterial load and suppressed excessive host immune response in the pneumonia mouse model. Accordingly, hinokitiol warrants further exploration as a potential candidate for the treatment of pneumococcal pneumonia.

DOI： 10.1371/journal.pone.0240329

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INTRODUCTION: This study aimed to develop a technique to create sequential slices, allowing the fluorescent visualization of bacterial viability in all parts of an infected dentin. METHODS: Cylindrical dentin blocks were prepared from freshly extracted human teeth with a single-rooted canal. Each block was immersed in 5% sodium hypochlorite (NaOCl) and 17% EDTA for 5 minutes before being infected with Enterococcus faecalis. The bacteria were allowed to develop inside dentin specimens for 28 days under anaerobic conditions. The specimens were exposed in 2% NaOCl for either 2 minutes or 20 minutes at 20°C, 37°C, and 45°C, respectively. After staining with calcein AM (Thermo Fisher Scientific, Waltham, MA) and propidium iodide, the samples were cryoembedded, mounted on an adhesive film, and sectioned at a thickness of 10 μm along the running of the dentinal tubules. Stacks of fluorescent images were collected in the z dimension using confocal laser scanning microscopy, and the maximum affected distance from a root canal was measured from the 3-dimensional reconstructed image. The reliability of this technique was verified by comparison with a dye bleaching test. RESULTS: Horizontal sequential sections preserving 3-dimensional bacterial distribution and their viabilities could be made without decalcification. The treatment time contributed to the penetration of NaOCl into dentinal tubules, whereas temperature did not significantly affect the penetration. The judgment by confocal laser scanning microscopic analysis was consistent with that of a dye bleaching test. CONCLUSIONS: The horizontal sectioning method has the advantage of creating sequential sections, allowing information to be imaged at every portion.

DOI： 10.1016/j.joen.2019.06.004

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Therapeutic mouthwash (MW) is an adjunctive tool along with a regular oral hygiene routine of daily tooth brushing and daily flossing. Previous systematic reviews have demonstrated that it is effective against dental biofilm and gingival inflammation, for prevention of dental caries, and for managing one's bad breath condition according to the active ingredients. MWs prevent the microorganisms from bacterial adhesion that corresponds to the initial step in biofilm formation. This review summarized the current state of evidence such as anti-biofilm, anti-gingivitis and cariostatic properties of MWs by evaluating systematic reviews from the past six years. The anti-biofilm property has been proven to be effective, with strong evidence of three main clinical efficacies. The most commonly studied active agent was chlorhexidine gluconate (CHX), followed by essential oil (EO) and cetylpyridinium chloride. All the systematic reviews are in complete agreement that CHX and EO provide statistically significant improvements in terms of plaque and gingival indices. These effects have held up over the years as the number of studies has increased. While the use of fluoride MW is proven to be effective in improving the oral health of both children and adults, the quality of evidence is still regarded as low.

DOI： 10.1016/j.jdsr.2018.07.001

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BioMed Central Ltd.  

Background: Chlorhexidine gluconate (CHG) has been proven to be effective in preventing and controlling biofilm formation. At the same time, an increase in calculus formation is known as one of considerable side effects. The purpose of this study was to investigate whether mineral deposition preceding a calculus formation would occur at an early stage after the use of CHG using an in vitro saliva-related biofilm model. Methods: Biofilms were developed on the MBEC™ device in brain heart infusion (BHI) broth containing 0.5% sucrose at 37 °C for 3 days under anaerobic conditions. Biofilms were periodically exposed to 1 min applications of 0.12% CHG every 12 h and incubated for up to 2 days in BHI containing a calcifying solution. Calcium and phosphate in the biofilm were measured using atomic absorption spectrophotometry and a phosphate assay kit, respectively. Morphological structure was observed using a scanning electron microscope (SEM), and chemical composition was analyzed with an electron probe microanalyzer (EPMA). Results: The concentrations of Ca and Pi following a single exposure to CHG increased significantly compared with the control. Repeatedly exposing biofilms to CHG dose-dependently increased Ca deposition, and the amount of Ca was five times as much as that of the control. Pi levels in CHG-treated biofilms were significantly higher than those from the control group (p &lt
0.05)
however, the influence of the number of exposures was limited. Analyses using an SEM and EPMA showed many clusters containing calcium and phosphate complexes in CHG-treated biofilms. Upon composition analysis of the clusters, calcium was detected at a greater concentration than phosphate. Conclusions: Findings suggested that CHG may promote mineral uptake into the biofilm soon after its use. It is necessary to disrupt the biofilm prior to the start of a CHG mouthwash in order to reduce the side effects associated with this procedure. The management of patients is also important.

DOI： 10.1186/s12903-018-0517-3

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE  

An ideal antibiofilm strategy is to control both in the quality and quantity of biofilm while maintaining the benefits derived from resident microflora. Vizantin, a recently developed immunostimulating compound, has also been found to have antibiofilm property. This study evaluated the influence on biofilm formation of Streptococcus mutans in the presence of sulfated vizantin and biofilm development following bacterial adhesion on a hydroxyapatite disc coated with sulfated vizantin. Supplementation with sulfated vizantin up to 50 mu M did not affect either bacterial growth or biofilm formation, whereas 50 mu M sulfated vizantin caused the biofilm to readily detach from the surface. Sulfated vizantin at the concentration of 50 mu M upregulated the expression of the gtfB and gtfC genes, but downregulated the expression of the gtfD gene, suggesting altered architecture in the biofilm. Biofilm development on the surface coated with sulfated vizantin was inhibited depending on the concentration, suggesting prevention from bacterial adhesion. Among eight genes related to bacterial adherence in S. mutans, expression of gtfB and gtfC was significantly upregulated, whereas the expression of gtfD, GbpA and GbpC was downregulated according to the concentration of vizantin, especially with 50 mu M vizantin by 0.8-, 0.4-, and 0.4-fold, respectively. These findings suggest that sulfated vizantin may cause structural degradation as a result of changing gene regulation related to bacterial adhesion and glucan production of S. mutans. (C) 2016 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bbrc.2016.10.021

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

Dental caries affects people of all ages and is a worldwide health concern. Streptococcus mutans is a major cariogenic bacterium because of its ability to form biofilm and induce an acidic environment. In this study, the antibacterial activities of magnolol and honokiol, the main constituents of the bark of magnolia plants, toward planktonic cell and biofilm of S. mutans were examined and compared with those of chlorhexidine. The minimal inhibitory concentrations of magnolol, honokiol and chlorhexidine for S. mutans were 10, 10 and 0.25 mu g/mL, respectively. In addition, each agent showed bactericidal activity against S. mutans planktonic cells and inhibited biofilmformationin a dose-andtime-dependent manner. Magnolol (50 mu g/mL) had greater bactericidal activity against S. mutans biofilm than honokiol (50 mu g/mL) and chlorhexidine (500 mu g/mL) at 5min after exposure, while all showed scant activity against biofilm at 30 s. Furthermore; chlorhexidine (0.5-500 mu g/mL) exhibited high cellular toxicity for the gingival epithelial cell lineCa9-22 at 1 hr, whereas magnolol (50 mu g/mL) and honokiol (50 mu g/mL) did not. Thus; it was found that magnolol has antimicrobial activities against planktonic and biofilm cells of S. mutans. Magnolol may be a candidate for prevention and management of dental caries.

DOI： 10.1111/1348-0421.12343

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

Chemical disinfection of oral biofilms often leaves biofilm structures intact. This study aimed to examine whether the residual structure promotes secondary bacterial adhesion. Streptococcus mutans biofilms generated on resin-composite disks in a rotating disc reactor were disinfected completely with 70% isopropyl alcohol, and were again cultured in the same reactor after resupplying with the same bacterial solution. Specimens were subjected to fluorescence confocal laser scanning microscopy, viable cell counts and PCR-Invader assay in order to observe and quantify secondarily adhered cells. Fluorescence microscopic analysis, particularly after longitudinal cryosectioning, demonstrated stratified patterns of viable cells on the disinfected biofilm structure. Viable cell counts of test specimens were significantly higher than those of controls, and increased according to the amount of residual structure and culture period. Linear regression analysis exhibited a high correlation between viable and total cell counts. It was concluded that disinfected biofilm structures favored secondary bacterial adhesion.

DOI： 10.1371/journal.pone.0116647

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

The aim of this study was to determine whether different antiseptic mouthrinses show different penetration kinetics into Streptococcus mutans biofilms.
The biofilms, grown on glass-based dishes, were exposed to one of four mouthrinses containing chlorhexidine digluconate, essential oil, cetylpyridinium chloride, or isopropylmethylphenol. Then, penetration velocities were determined by monitoring fluorescence loss of calcein AM-stained biofilms with time-lapse confocal laser scanning microscopy. Bactericidal activity was assessed with fluorescent bacterial viable cell (Live/Dead) staining and viable cell counts. Bacterial detachment after the mouthrinse exposure was determined by measuring fluorescence reduction of SYTO9-stained biofilms.
The essential oil-containing mouthrinse showed significantly faster penetration velocity than the other mouthrinses (ANCOVA and Bonferroni test, p &lt; 0.05). However, even 5 min of exposure left the biofilm structure almost intact. After 30 s (consumer rinsing time) of exposure, the essential oil-containing mouthrinse showed the highest log reduction of viable cells (2.7 log CFU) measured by Live/Dead staining, and the mean reduction of total viable cells was 1.41 log CFU measured by viable cell count.
The essential oil-containing mouthrinse showed the best penetration. Within 30 s of exposure, however, no mouthrinses injured all the microorganisms and all mouthrinses left the biofilm structure nearly intact.
The mouthrinses tested showed different levels of biofilm penetration. The essential oil rinse was superior to other rinses by all three of the in vitro measurements performed.

DOI： 10.1007/s00784-013-1002-7

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Language：English   Publisher：Japanese Association for Oral Biology  

Oral biofilms, unlike those formed at most other sites in the human body, are unique because surgical intervention is usually unnecessary for their removal. The control of oral biofilms relies mainly on mechanical elimination. Chemical controls are used as alternative or adjunctive methods when elimination using dental instruments proves difficult. For many years, researches have focused on how microorganisms could be rapidly killed using high concentrations of antimicrobials or new antibacterial agents. New strategies that target the matrices of mature biofilms are needed because biofilm matrices inhibit the effect of antimicrobial agents through absorption and degradation. These strategies include the following possibilities: (1) use of antimicrobial agents with superior penetration properties and (2) degradation or detachment of matrix polymers. In order to investigate the penetration properties of antimicrobial agents, time-lapse microscopy can be used for noninvasive visualization of antimicrobial action inside models of oral biofilms. Factors that affect drug penetration properties include molecular weight, charge, hydrophilic-hydrophobic balance, and malabsorption/modification by the biofilm matrix. However, strategies that rely on antimicrobial agents have an important limitation. Even if the microorganisms are eradicated, their biofilm structure remains intact and may promote secondary biofilm and tartar formation. Therefore, future strategies should shift their focus to degradation and/or removal of matrix polymers. Some detachment-promoting agents have been reported. These agents have the potential to control biofilm accumulation effectively. Since the clinical efficacy remains unclear, and in addition to limitations of targeting a specific polysaccharide component and retention properties, further investigations are warranted. © 2012 Japanese Association for Oral Biology.

DOI： 10.1016/j.job.2012.09.002

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MOSHER & LINDER, INC  

Purpose: To estimate the color-masking ability of two polymer-based paint-on temporary coating materials, White Coat and BeautiCoat. Methods: Three shades (OA1, OB0, OB1) of White Coat and four shades (BW1, BW2, BW3 and BW4) of BeautiCoat were used. Disk specimens (0.25-2.0 mm thick) were prepared, CIELAB coordinates (L*, a*, b*) were measured against white and black backgrounds on a colorimeter, and translucency parameter (TP) was calculated. Masking effect (Delta ME*ab) was also calculated as the color difference between a specimen over a black background and black background itself. Measurements were also made on a dentin-shaded resin composite as a substitute for discolored teeth, and color differences (Delta E*) were then calculated. Results: The TP value decreased as the thickness of the specimen increased, and non-linear regressions were shown between the specimen thickness and TP value for all materials evaluated (P&lt; 0.01). TP values of BeautiCoat showed significant differences (P&lt; 0.05) between each shade at any thickness evaluated, ranging from 20.0 to 46.4 at 0.25 mm in thickness. White Coat showed narrower-ranging TP values: from 20.0 to 23.5 at 0.25 mm, and differences were often insignificant. Delta ME*ab values correlated with TP values. Delta E* values of 0.25 mm-thick specimens against the dentin-shade composite were above 6.5, which can be evaluated as visually perceptible. (Am J Dent 2009;22:361-365).

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER SOC MICROBIOLOGY  

The diffusive penetration of fluorescently tagged macromolecular solutes into model oral biofilms was visualized by time-lapse microscopy. All of the solutes tested, including dextrans, proteases, green fluorescent protein, and immunoglobulin G, accessed the interior of cell clusters 100 to 200 mu m in diameter within 3 min or less.

DOI： 10.1128/AEM.02279-08

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

The purpose of this study was to examine whether Streptococcus mutans is implicated in the generation of fluorescence detected in carious lesions. Enamel surfaces and dentin cavities of extracted human teeth were subjected to artificial caries generation by exposing them either to a culture medium containing S. mutans or to a lactic acid buffer for 2 weeks. Fluorescence from the lesions was detected with confocal laser scanning microscopy or fluorescence microscopy at various excitation wavelengths, and maximum fluorescence radiance was computed using image-analyzing software. Culture media of S. mutans were also examined for fluorescence generation. The results demonstrated that S. mutans-induced enamel and dentin lesions exhibited increased fluorescence in the red and green spectral regions, with the signal stronger in the red region. In the blue region, however, fluorescence signals in the corresponding area were below the background level. Significantly weaker or virtually no fluorescence was detected in lactic acid-demineralized lesions at all excitation wavelengths. Neither bacterial cells nor culture media generated any fluorescence. These results indicate that, although the presence of S. mutans may be a prerequisite for the emission of fluorescence from carious lesions, some interaction of S. mutans with exposed tooth matrix elements may also be required for the generation or unmasking of fluorophores.

DOI： 10.1007/s10266-007-0077-5

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER SOC MICROBIOLOGY  

A microscopic method for noninvasively visualizing the action of an antimicrobial agent inside a biofilm was developed and applied to describe spatial and temporal patterns of moutbrinse activity on model oral biofilms. Three species biofilms of Streptococcus oralis, Streptococcus gordonii, and Actinomyces naeslundii were grown in glass capillary How cells. Bacterial cells were stained with the fluorogenic esterase substrate Calcien AM (CAM). Loss of green fluorescence upon exposure to an antimicrobial formulation was subsequently imaged by time-lapse confocal laser scanning microscopy. When an antimicrobial mouthrinse containing chlorhexidine digluconate was administered, a gradual loss of green fluorescence was observed that began at the periphery of cell clusters where they adjoined the flowing bulk fluid and progressed inward over a time period of several minutes. Image analysis was performed to quantify a penetration velocity of 4 mu m/min. An enzyme-based antimicrobial formulation led to a gradual, continually slowing loss of fluorescence in a pattern that was qualitatively different from the behavior observed with chlorhexidine. Ethanol at 11.6% had little effect on the biofilm. None of these treatments resulted in the removal of biomass from the biofilm. Most methods to measure or visualize antimicrobial action in biofilms are destructive. Spatial information is important because biofilms are known for their structural and physiological heterogeneity. The CAM staining technique has the potential to provide information about the rate of antimicrobial penetration, the presence of tolerant sub-populations, and the extent of biomass removal effected by a treatment.

DOI： 10.1128/A-EM.02218-07

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPANESE SOC DENTAL MATERIALS DEVICES  

Removal of resin-based root canal filling materials may cause serious problems during root canal retreatment. This study compared the working time and amount of canal enlargement when different resin-based root canal filling materials were removed with K3 rotary instruments with or without heat-softening using System B. Root canal sealer/filling point combinations tested were Epiphany/Resilon, SuperBond/Resilon, SuperBond/gutta-percha, and Canals N/gutta-percha. The materials were filled into simulated curved resin canals and removed with K3 instruments in a standardized crown-down procedure. In terms of working time, Epiphany/Resilon required a significantly longer working time than the others. However, heat application with System B significantly reduced the working time for the removal of Epiphany/Resilon. In terms of canal enlargement, there were no significant differences among the tested groups as determined with digital morphometry. It was thus concluded that Epiphany removal with K3 rotary instruments might result in extended working time, but which could be reduced with heat-softening using System B.

DOI： 10.4012/dmj.27.75

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

The aim of this study was to establish a method for quantitative differential counting of live/dead anaerobic microorganisms. Artificial biofilms of Peptostreptococcus anaerobius 4330-1, one of the strictest anaerobes, were made on filters of 0.4 μM pore size. A commercial Live/Dead BacLight Bacterial Viability Kit using propidium iodide (PI) and SYTO9 fluorescent staining was found to be suitable for the facultatively anaerobic organism Propionibacterium acnes. However, P. anaerobius seemed to reduce SYTO9 and change fluorescent intensity, which made the kit unsuitable for this anaerobe. As an alternative method suitable for even P. anaerobius, a combination of phase-contrast microscopy and PI staining was adapted. Bacterial numbers could be counted in phase-contrast microscopic fields, and PI-positive organisms were counted as dead organisms in the same field. Only 3.8% of P. anaerobius cells in artificial biofilms were found to be PI-positive after exposure to air for 24 h, while 44% of planktonic P. anaerobius cells were PI-positive after exposure to air for 24 h. Similarly, 38% of P. anaerobius cells were PI-positive when organisms were collected onto filters to make bacterial masses and thereafter exposed to air for 24 h. These results indicate that P. anaerobius is highly aerotolerant in biofilms.

DOI： 10.1080/08910600410023925

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MUNKSGAARD INT PUBL LTD  

The present study investigated whether extracellular polysaccharides inhibit reaction between Streptococcus mutans and its specific immunoglobulin G (IgG) and penetration of the IgG through S. mutans biofilm. The planktonic organisms with or without extracellular polysaccharides were prepared, incubated with rabbit IgG against whole cell of S. mutans and fluorescein isothiocyanate (FITC)-conjugated goat affinity purified antibody to rabbit IgG. Biofilms with or without extracellular polysaccharides were formed on cover glasses and incubated with rabbit IgG against S. mutans and FITC-conjugated goat antibody to rabbit IgG. Then, biofilms were stained with propidium iodide. The amount of specific IgG binding on S. mutans was determined by FITC intensity with a fluorescence microplate reader. The penetration of IgG through biofilms was determined by confocal laser scanning microscopy. The results showed that the fluorescence intensity of FITC in planktonic organisms with extracellular polysaccharides was similar to that in planktonic organisms without extracellular polysaccharides, indicating that extracellular polysaccharides did not inhibit the reaction between S. mutans and its specific IgG. Although biofilms of S. mutans with extracellular polysaccharides were much thicker and denser than those without extracellular polysaccharides, the speed with which IgG penetrated through both of the biofilms did not differ significantly, suggesting that penetration of Ige through S. mutans biofilm was not affected by extracellular polysaccharides.

DOI： 10.1034/j.1399-302X.2001.160109.x

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MUNKSGAARD INT PUBL LTD  

The aim of this study was to investigate acid resistance induced by starvation or biofilm formation in Streptococcus mutans ATCC 25175. The artificial biofilms were made on cover glasses, starved for 24 h and immersed in 0.1 M lactate buffer at pH 3.8 for 10 min. The biofilms were also exposed to 5% sucrose solution for 20 min to simulate acid shock produced by sucrose metabolism. Confocal laser scanning microscopy with fluorescein isothiocyanate staining measured the resultant minimum pH in biofilms. Live and dead organisms in biofilms were differentiated by confocal laser scanning microscopy with proidium iodide and SYTO9 staining. The same processes were used to treat planktonic organisms. The results showed that starved biofilms or planktonic cells showed significantly more viable bacteria after acid shock induced either by lactic acid or during sucrose consumption than non-starved biofilms or planktonic cells. In addition, biofilms showed greater resistance to acid shock induced by lactic acid than planktonic cells, whereas similar results were obtained where sucrose was used as a carbon source to reduce pH in biofilms and planktonic cells. Thus, it is suggested that starvation protects both biofilm and planktonic S. mutans from acid shock induced either by lactic acid or during sucrose consumption, while biofilm formation seemed to protect bacteria only from acid shock induced by pH 3.8 lactate buffer but not the acid shock of a slightly higher pH produced during sucrose consumption.

DOI： 10.1034/j.1399-302X.2001.160104.x

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

Bacterial biofilms may be formed at various sites, including mucous membranes, teeth, and infectious lesions. To elucidate the structure and the function of biofilms, artificial biofilms of mucoid-type Pseudomonas aeruginosa organisms (strain PT1252) were made by centrifuging the organisms onto the surface of a coverglass and culturing further in broth media supplied continuously (45 ml/h). The biofilm structure at 4, 8, 12, and 24h was visualized with fluorescent staining (SYTO9, propidium iodide [PI], and/or fluorescein isothiocyanate-concanavalin A [FITC-ConA]) by confocal laser scanning microscopy (CLSM). It was clearly demonstrated that the number of bacteria (104-106/ml) could be estimated by their fluorescence intensity. Sectional analysis of each biofilm layer (1-μm thickness) made it possible to demonstrate the three-dimensional development of biofilms, and revealed that the biofilms were 9μm in height after 12h. The live and dead organisms were differentiated by SYTO9 and PI, respectively, in situ in biofilms, and about 13% of the organisms were dead in 12-h-old biofilms. When 12-h-old biofilms were exposed to ciprofloxacin at minimum bactericidal concentration (6.26μg/ml) for 90min, all the organisms were killed, but some organisms (11 ± 1.3%
n = 3) in 24-h-old biofilms with thicker and denser structure were still alive after exposure for 120min. These results indicate that the CLSM analysis of artificial biofilms was useful for elucidating bacterial functions in biofilms, and may lead to a new quantitative system for estimating the bactericidal efficacy of antibacterial drugs in biofilms.

DOI： 10.1007/s101560100014

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Total pages：157  

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Language：Japanese   Publisher：(株)ヒョーロン・パブリッシャーズ  

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Language：Japanese   Publisher：(NPO)日本歯科保存学会  

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Language：Japanese   Publisher：(株)北隆館  

地域包括ケアシステムの確立が推進される中で、在宅高齢者の身体状態の変化を察知するリスクアセスメントが重要となっている。我々は、地域包括ケアで活躍する訪問看護師のリスクアセスメント力を支援することを目的として、看護学の専門家を中心として、医学、歯学、工学の研究者が集う異分野融合研究チームを結成し、在宅で誤嚥性肺炎発症のリスクを判定可能な科学的評価システムの研究・開発を行っている。(著者抄録)

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Language：Japanese   Publisher：(NPO)日本歯科保存学会  

目的:硫酸化ビザンチン(Viz-S)は,50μmol/lではStreptococcus mutansバイオフィルムを易剥離性に変化させ,75μmol/lでは付着を抑制する.本研究では,75μmol/l Viz-Sの付着抑制機序を解明するため,同菌の表面性状の変化および付着関連遺伝子の転写量の変化について解析した.材料と方法:実験1(菌体表面性状の解析);S.mutans UA159株(UA159)のPBS懸濁液1mlに,Viz-Sを終濃度が0,50,75μmol/lとなるように添加した.10分間作用させたのち,n-ヘキサデカン200μlを添加し1分間攪拌した.15分間静置後,疎水性率をMicrobial adhesion to hydrocarbon testにより評価した.実験2(Viz-S処理したS.mutansの付着抑制効果);0.2,0.4,0.8,1.6%スクロース含有BHI液体培地に,終濃度が0,50,75μmol/lとなるようにViz-Sを添加した.緑色蛍光タンパク質を導入したS.mutans変異株(ZsG)を,OD600=0.025となるように培地に加えた.唾液処理したカバーガラスチェンバー内に細菌懸濁液を送り込み,1時間静置後の付着細菌の割合を,共焦点レーザー顕微鏡を用いて解析した.実験3(遺伝子発現動態の解析);0,50,75μmol/lのViz-S存在下で4時間培養後のUA159を回収し,mRNAを抽出後,cDNAを合成した.付着関連遺伝子の転写量をReal-time PCR法で解析した.成績:コントロール群の菌体表層の疎水性率(%±SD)は57.5±13.4であった.50μmol/lおよび75μmol/lのViz-S存在下では疎水性率が低下し,それぞれ,29.4±10.4(p<0.05),14.9±7.0(p<0.01)であった.50μmol/lおよび75μmol/l Viz-S群のZsGの付着面積は,コントロール群と比較して,それぞれ1/8〜1/10(50μmol/l Viz-S群)および1/40〜1/55(75μmol/l Viz-S群)に減少した.gtfDの転写は,すべてのスクロース含有条件でコントロール群と比較して,それぞれ0.38〜0.5倍(50μmol/l Viz-S群)および0.33〜0.36倍(75μmol/l Viz-S群)に有意に低下した(p<0.05).菌体表層タンパクをエンコードする遺伝子群の転写には有意な変化はなかった.結論:50μmol/lおよび75μmol/lのViz-Sは,S.mutansの菌体表層に結合することで,表面性状を親水性に変化させた.また,スクロース依存性の付着に重要なgtfDの転写を低下させた.75μmol/lのViz-Sは,これらの2つの機序によりS.mutansに対して付着抑制効果を示すと考えられた.(著者抄録)

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Language：Japanese   Publisher：(NPO)日本歯科保存学会  

目的:機能性糖脂質ビザンチン(Viz-S)は,Streptococcus mutansバイオフィルムを易剥離性に変化させることで抗バイオフィルム作用を示す.本研究では,培養条件のうち,スクロース濃度を変化させたときのS.mutansの抗バイオフィルム効果,各種バイオフィルム形成関連遺伝子の転写量ならびにグルコシルトランスフェラーゼ(GTF)の発現について解析を行った.材料と方法:実験1・スクロース濃度を変化させたときのS.mutansの抗バイオフィルム効果;0.2,0.4,0.8%および1.6%のスクロース含有Brain Heart Infusion培地に,0,10,50μmol/lおよび75μmol/lのViz-Sを添加した.S.mutans UA159株を24時間嫌気培養することで,in vitroバイオフィルムモデルを作製した.リン酸緩衝生理食塩水(PBS)で2回洗浄したときの残存バイオフィルム量をクリスタルバイオレット法(CV法)により定量した.実験2・遺伝子発現動態の解析;0,10μmol/lおよび50μmol/lのViz-S存在下で24時間培養後のバイオフィルム形成菌を回収し,mRNAを抽出後,cDNAを合成した.バイオフィルム形成関連遺伝子の転写量をReal-time PCR法で解析した.実験3・ウエスタンブロッティング解析;in vitroバイオフィルムモデルを作製後,バイオフィルム形成菌と上清をそれぞれ回収した.タンパク質を抽出しSDS-PAGEを行った.疎水性膜に転写し,菌体結合型GTF(CA-GTF)抗体および遊離型GTF(CF-GTF)抗体を反応させた後,酵素標識二次抗体を反応させた.化学発光法により可視化し,タンパクの発現量を比較した.成績:10μmol/l Viz-S群のバイオフィルムは,PBSによる2回の洗浄により構造は変化しなかったが,50μmol/l Viz-S群は0.8%までのスクロース含有条件下においてバイオフィルム構造が93%減少した.1.6%のスクロース含有条件では32%のバイオフィルムが残存した.75μmol/l Viz-S群は,全スクロース濃度においてバイオフィルム形成が阻害された.10μmol/l Viz-S群は,すべての条件下において,遺伝子転写量の有意な変化はなかった.50μmol/l Viz-S群のgtfBおよびgtfC遺伝子の転写は,0.4%以上のスクロース含有条件で,コントロール群(Viz-S非含有)と比較して有意に増加したが,gtfDの転写は,すべてのスクロース含有群で0.46〜0.66倍に減少した.ウエスタンブロッティング解析で50μmol/l Viz-S群のGTFBおよびGTFCの産生量を比較したところ,コントロール群と比較して0.2%および0.4%スクロース含有条件下で有意に低下し,0.8%および1.6%スクロース含有条件下で有意に増加した.一方,GTFDは,コントロール群と比較して1/20以下に産生量が減少した.結論:50μmol/lのViz-Sは口腔粘膜への為害性が低く,殺菌ではない機序でS.mutansのバイオフィルムを剥離した.その機序の一つは,GTFDのタンパク発現を低下させることによるバイオフィルムの構造安定性の低下であった.75μmol/lのViz-Sはバイオフィルム形成を抑制した.(著者抄録)

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Language：Japanese   Publisher：新潟歯学会  

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Language：Japanese   Publisher：日本バイオフィルム学会  

口腔において洗口液をはじめとする抗菌成分は、唾液により希釈され時間経過とともに最小発育阻止濃度以下(sub-minimum inhibitory concentration:sub-MIC)となるため、逆にバイオフィルム形成(BF)を促進する可能性がある。そこで本研究では、う蝕病原細菌であるStreptococcus mutans、Streptococcus oralisおよびActinomyces naeslundiiの3菌種から成るin vitro複合バイオフィルムモデルを確立し、sub-MICのグルコン酸クロルヘキシジン(CHG)を作用させた際のS.mutansの局在とBFおよびクオラムセンシング関連遺伝子の転写量の変化について検討した。S.mutansはUA159株と緑色蛍光タンパク発現株(ZsGreen株)の2種類を用いた。SEM像より、コントロール群、CHG作用群ともに球菌を主体とするバイオフィルムが観察された。CLSM像より、CHG作用群はコントロール群と比較してバイオフィルムの厚みが有意に増していた。またCLSMにて構成細菌の局在を観察したところ、S.oralisとA.naesulundiiはバイオフィルム深部に局在し、S.mutans(ZsGreen株)はバイオフィルム中の表層部に局在していた。CHGの有無による局在の差は認めなかった。バイオフィルム中の生菌数は、CHG群とコントロール群で有意差はなかった。バイオフィルム中の各細菌種の割合は、両群とも9割以上Streptococcus属が占有していた。0.24 μg/ml CHG作用群のS.mutansでは、gtfCおよびcomDの転写量がコントロール群と比較し有意に増加していた。このことから今回作製した3菌種による複合バイオフィルムモデルにおいて、sub-MICのCHGは、S.mutansのBF形成関連遺伝子に影響を与えることでBFを促進させることが示唆された。(著者抄録)

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Language：Japanese   Publisher：日本バイオフィルム学会  

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Language：Japanese   Publisher：日本バイオフィルム学会  

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Language：Japanese   Publisher：新潟歯学会  

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Language：Japanese   Publisher：(NPO)日本歯科保存学会  

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Language：Japanese   Publisher：(NPO)日本歯科保存学会  

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Language：Japanese   Publisher：日本バイオフィルム学会  

殺菌に頼ったバイオフィルム(BF)制御は口腔細菌叢の変化の懸念があるだけでなく、付着界面にBF構造が残存し、BF再形成の足場となる可能性が指摘されている。本研究では、結核菌の表層糖脂質をリード化合物として創製した機能性糖脂質(硫酸化ビザンチン:Viz-S)が、ヒト唾液由来細菌のex vivoモデル上でのBF形成に与える影響について検討するとともに、初期定着菌に対する付着抑制効果について検討した。Sub-MIC量のViz-S存在下で24時間培養後のex vivoBF量をクリスタルバイオレット(CV)法で定量したところ、BF量は50μM以上で有意に減少した。蛍光染色を施し、共焦点レーザー顕微鏡(CLSM)観察を行うと、Viz-SはBF中の細菌に殺菌効果を示さず、BF量は濃度依存的に減少した。初期定着菌に各濃度のViz-S溶液を10分間作用させたのち菌体表面性状を評価したところ、100μMにおいて疎水度は有意に低下した。また、50μMもしくは100μMのViz-Sで10分作用後のStreptococcus mutansのガラス表面への細菌付着量をフローセルを用いて解析したところ、ガラス界面への付着量は濃度依存的に減少していた。さらに、Viz-Sを蛍光標識し、S.mutans菌液と混合したのち蛍光顕微鏡観察すると、リング状に蛍光を発する菌体が観察された。これらのことから、Viz-Sはsub-MIC量において細菌壁表層の性状を親水性に変化させることで付着減弱効果を与え、菌種非特異的にBFを易剥離性に変化させることが示唆された。Viz-Sは口腔細菌叢を変動させない新しいBF制御剤として有用である可能性が示された。(著者抄録)

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Language：Japanese   Publisher：(株)デンタルダイヤモンド社  

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Language：Japanese   Publisher：(NPO)日本歯科保存学会  

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Language：Japanese   Publisher：日本バイオフィルム学会  

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Language：Japanese   Publisher：(NPO)日本歯科保存学会  

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Language：Japanese   Publisher：日本バイオフィルム学会  

厚朴由来の抽出物でポリフェノールであるMagnololおよびHonokiolは、生薬として広く用いられ、抗菌作用を有するとされている。本研究では、Streptococcus mutansバイオフィルムに対するMagnololおよびhonokiolの殺菌効果および細胞毒性について検討した。ガラスボトムディッシュ上に形成したS.mutans人工バイオフィルムに対し、Magnolol、Honokiol、およびクロルヘキシジングルコン酸塩を30秒および5分作用させたときの殺菌効果をコロニー数測定法および蛍光プロービング法を用いて評価したところ、Magnolol作用群は、5分作用後において他群と比較して有意に高い殺菌効果を示した。さらに、ヒト歯肉上皮細胞株Ca9-22に対する各抽出物の細胞毒性をMTT試験にて評価したところ、Magnololは、有効殺菌濃度においてヒト歯肉上皮細胞に対して細胞毒性を示さなかった。以上のことから、MagnololはS.mutansバイオフィルムに対する優れた殺菌効果を有し、口腔粘膜への副反応が低いことが示唆された。(著者抄録)

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Language：Japanese   Publisher：日本歯科医学教育学会  

歯学教育を改善するために、各大学歯学部・歯科大学においてさまざまな取り組みが行われている。なかでも、診療参加型の臨床実習を充実させることは重視されており、それぞれの歯学部・歯科大学は信頼される歯科医師を輩出するという最も大きな社会的命題を果たすべく努力を続けている。新潟大学歯学部では、卒業生の質の保証を目的に、臨床実習においてACCEPT Projectを立ち上げ、「ACKPIS」と称する方法を用いて学生の臨床能力を評価してきた。ACKPISは診療を自験する学生に対し、どのような専門領域においても必要不可欠となる6つの基本項目を、それぞれの専門処置を評価課題として確認するものである。今回、ACKPISの効果を検証するために、平成28年度の受検生にアンケート調査を行った。ACKPISの基本項目は、ADEAやGDCが提唱する歯科医師に求められるコンピテンシーの中にも該当する記述がみられ、国内外で医師に対して行われている臨床能力評価法同様、診療現場でのフィードバックを含んでいることから、歯学生の臨床能力を評価するために適当であると考えられた。また、アンケート結果から、受検した学生もACKPISの必要性や重要性を認識し、受検方法や合否判定の妥当性を認めていることが明らかになった。以上のことから、ACKPISは臨床実習中の学生の臨床能力を評価するための有用な方法となり得ることが示唆された。(著者抄録)

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Language：Japanese   Publisher：(公財)8020推進財団  

高齢者の介護予防のための口腔機能評価および管理からなる包括的システム(システム)を開発した。介護型のケアハウス入所者25名(男性4名、女性21名、平均83.9±6.4歳)を対象とし、「お口の元気度検査」として口腔機能検査、全身状態などについての検査を行った。プレフレイルまたはフレイルと判定された者が84%、サルコペニアと判定された者が判定1では28%、判定2では56%で、栄養状態については低栄養が8%、低栄養のリスク有が28%であった。オーラルディアドコキネシスという「pa」「ta」「ka」音それぞれを10秒間連続発声して口腔機能を評価する方法で判定し、フレイルと判定された入所者は「pa」「ta」「ka」音いずれも基準値未満が多かった。咀嚼力判定ガムを用いて評価し、フレイルと判定された入所者は、咀嚼力が低かった。

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Language：Japanese   Publisher：(NPO)日本歯科保存学会  

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

本研究では、セルフケアにおける洗口液の継続使用に影響する要因を探索するために、新潟大学医歯学総合病院・歯の診療室に歯周基本治療あるいはメインテナンスのために受診した68名の患者を対象として、機械的清掃器具の使用頻度、洗口液の使用経験および使用感に関する質問票調査を行った。洗口液使用者には、使用理由、期待する性質および選定時に重要視する要素を調査した。使用感は、国内で市販されている四種類の洗口液[コンクールF(CHG)、リステリン(LF)、リステリンナチュラルケア(LN)、薬用GUMナイトケアBF(CP)]の味、刺激、爽快感、効果の実感および全体的な印象について、二重盲検法(LFは単盲検法)により5段階評価を行う形式で調査し、それぞれの評価項目の相関分析を行った。洗口液の使用経験者は37名(54.4%)であり、洗口液の常用者は18名(26.5%)であった。洗口液選定時に重要視する要素の順位付けには一致性があり、優れた殺菌力、爽快感および味が上位要素であった。使用感調査において、CPおよびCHGの全体的な印象は、LFおよびLNと比較して有意に評価が高かった。LFとLNはすべての評価項目において有意な差は認められなかった。相関分析において、味が最も全体的な印象と相関性が高かった。洗口液に求められる性質として、殺菌効果だけでなく、継続使用のためには味や爽快感も重要な要素であることが示唆された。(著者抄録)

DOI： 10.5834/jdh.66.4_361

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Other Link： http://search.jamas.or.jp/link/ui/2015212350

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Language：Japanese   Publisher：(株)第一歯科出版  

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Language：Japanese   Publisher：(NPO)日本歯周病学会  

本研究では、リステリンの刺激性や使用感の改善を意図して開発された新規アルコール非含有洗口液(リステリンナチュラルケア;N群)のStreptococcus mutans人工バイオフィルムに対する浸透性と殺菌能を既存洗口液[Listerine Zero(Z群)、リステリンフレッシュミント(F群)および0.12%グルコン酸クロルヘキシジン含有洗口液(CHG群)]との比較により評価した。人工バイオフィルムはガラスベースディッシュ上で24時間嫌気培養することにより作製した。洗口液の浸透性はcalcein-AMで染色したバイオフィルムの底面の蛍光消失を共焦点レーザー顕微鏡で経時的に解析することにより評価した。殺菌能は30秒作用後の生菌数測定およびバイオフィルム底面のLive/Dead染色像により評価した。その結果、各洗口液とも50%蛍光消失時間はバイオフィルムの厚みと正の相関を示し、N群の浸透速度はZおよびF群と同等かつCHG群より有意に高値であった。生菌数はN、ZおよびF群は同等で共にCHG群より有意に低値であった。また、Live/Dead染色像はN、ZおよびF群とも99%以上がpropidium iodide(PI)陽性細菌であり陽性率はCHG群より有意に高かった。以上の結果から、N群の浸透性と殺菌能は、Z群およびF群と同等かつCHG群より有意に優れていることが示された。(著者抄録)

DOI： 10.2329/perio.56.291

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Language：Japanese   Publisher：(NPO)日本歯周病学会  

新潟大学医歯学総合病院・歯の診療室に歯周基本治療あるいはメインテナンスのため受診した患者を対象に、洗口液の使用状況と使用感に関するアンケート調査を行った。口腔ケア製品(補助清掃器具と洗口液)の使用状況を質問票により調査するとともに当日のプラークコントロールレコードを記録した。洗口液使用者には、使用理由、期待する性質および選定時に重要視する要素を調査した。洗口液の使用感については主成分の異なる四種類の洗口液[コンクールF(CHX;ウェルテック社製)、リステリンフレッシュミント(EO;J&amp;J社製)、ピュオーラ洗口液クリーンミント(PU;花王社製)、GUMデンタルリンスナイトケア(CP;サンスター社製)]の味および使用感を二重盲検法(EOは単盲検法)により調査した。被験者は一日平均2.8回歯磨きをしており、87%(46名)が補助清掃器具を使用していた。洗口液もしくは液体歯磨の使用者は38%(20名)であり、洗口液使用者のプラークスコアは非使用者と比較して有意に低かった。選定時に重要視する要素の順位付けには一致性があり、「優れた殺菌力」、「爽快感」、「味」が上位要素であった。洗口液の「味」と「使用感」には正の相関関係があり、いずれもCHX&gt;CP&gt;PU&gt;EOの順で評価が高かった。洗口液の選定には歯科医師・歯科衛生士からの推奨や動機づけが最も影響を与えると思われた。洗口液に患者が求める性質として、う蝕・歯周病予防効果や殺菌効果への期待とともに、味や使用感も重要な要素であることが示唆された。(著者抄録)

DOI： 10.2329/perio.55.148

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Language：Japanese   Publisher：日本バイオフィルム学会  

これまで、成熟した口腔内バイオフィルムへの対応は、細菌をターゲットとしていかに迅速に殺菌するかが重要視されてきた。しかし、口腔内で使用される抗菌成分を用いた化学的コントロール法は、唾液による自浄作用や舌・口唇の動き、嚥下といった口腔機能の働きにより口腔内長時間保持が困難なため、バイオフィルムの厚みの増加とともに深層部への効果は減弱する。さらに、口腔内は常在菌が存在する特殊な器官であるため、バイオフィルム中の細菌が殺菌されたとしてもバイオフィルム構造が付着界面に残存した場合、新たなバイオフィルム形成の足場となる可能性がある。本研究では、Rotating Disc Reactorを用いて1日あるいは3日培養することにより作製したS.mutansバイオフィルムを殺菌後に対数増殖期の細菌培養液を灌流させ、死菌量の異なるバイオフィルム構造への二次付着量を比較検討した。その結果、殺菌処理後に残存するバイオフィルム構造に新たな浮遊細菌の付着が生じやすく、残存するバイオフィルム構造の量の増加とともに有意に付着細菌数も増加した。このことから、残存バイオフィルム構造が新たなバイオフィルム形成の起点となることが示唆され、殺菌効果だけに頼ったバイオフィルム制御戦略から、マトリックス結合を減弱・分散あるいは付着界面から剥離する戦略への転換が合理的と思われた。(著者抄録)

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Language：Japanese   Publisher：(株)デンタルダイヤモンド社  

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Language：Japanese   Publisher：(NPO)日本歯科保存学会  

目的:リステリンはバイオフィルム中の細菌に対して短時間で膜傷害効果を示すと報告されているが,溶剤としてエタノールを含むため粘膜刺激性の強さが短所であった.本研究ではこの点の改良を意図して開発されたノンアルコールタイプのListerine Zeroについて,Streptococcus mutansバイオフィルムに対する浸透性および殺菌能を評価した.材料と方法:Listerine Zero(Z群),リステリンフレッシュミント(F群)およびグルコン酸クロルヘキシジン含有洗口液(Peridex,P群)を被験洗口液とし,陰性対照として緩衝液(C群)を用いた.また,S.mutansバイオフィルムはガラスベースディッシュを用いて24時間,嫌気培養により形成した.各洗口液の浸透性は,Calcein-AMで蛍光染色されたバイオフィルムに各洗口液を作用させた後,共焦点レーザー顕微鏡により蛍光消失のタイムラプス解析を行い測定した.また,生死鑑別(Live/Dead)蛍光染色法およびプレートカウント法を用いて,各洗口液の殺菌効果を比較した.結果:バイオフィルムの最大厚みは32μmであった.各洗口液とも50%蛍光消失までの時間(T50)はバイオフィルムの厚みと正の相関関係があり,それぞれy=2.012x,決定係数(R2)=0.992(Z群),y=1.992x,R2=0.986(F群),y=10.579x,R2=0.994(P群)であった.浸透速度はP群が他群より有意に低値であったが(共分散分析,p&lt;0.05),Z群,F群間には有意差はなかった(同,p&gt;0.05).各洗口液30秒作用後にLive/Dead染色法にてPropidium Iodide(PI,死菌のマーカー)陽性率を比較したところ,F群,Z群は99.8±0.1%を示したがP群では41.4±5.9%であった.さらに,30秒作用後の生菌数をプレートカウント法で求めたところ,すべての洗口液群がC群と比較して有意に少数(Dunnett test,p&lt;0.05),またF群およびZ群はP群より有意に少数であったが(Steel-Dwass test,p&lt;0.05),F群とZ群の間に有意差はなかった(同,p&gt;0.05).結論:Listerine Zeroおよびリステリンは,少なくとも32μm以下の厚みのS.mutansバイオフィルムに対して同等の膜傷害効果と殺菌効果を与えた.また,Listerine Zero,リステリンともグルコン酸クロルヘキシジン含有洗口液と比較して有意に高いバイオフィルム浸透性と殺菌効果を示した.(著者抄録)

DOI： 10.11471/shikahozon.56.105

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Language：Japanese   Publisher：デンタルダイヤモンド社  

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Language：Japanese   Publisher：(公財)8020推進財団  

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Language：Japanese   Publisher：(公社)日本歯科医師会  

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Language：Japanese   Publisher：日本バイオフィルム学会  

共焦点レーザー顕微鏡を用いた蛍光イメージングによるバイオフィルム中の細菌の生死判定法は、その三次元構造を破壊することなくバイオフィルム深層部を観察できるものの、染色時の一時点の情報しか得られない欠点があった。本研究では、Calcein-AM(CAM)染色法と共焦点レーザー顕微鏡を用いて、バイオフィルムの深層部に対する洗口液の膜傷害効果をリアルタイムに観察した。バイオフィルムの厚み(概算値)は最大で31.5μmであった。ガラスベースディッシュを用いて静置にて24時間嫌気培養することにより形成したStreptococcus mutansバイオフィルムにCAM染色を施した後、バイオフィルム底面の洗口液作用後の膜傷害効果を観察したところ、厚みの薄い部分から徐々に蛍光が消失した。50%および90%蛍光量減少までの時間(T50、T90)は、バイオフィルムの厚みと正の相関関係にあった。洗口液30秒作用後の生菌数は有意な減少は認められるものの、10^9cfu/ml以上が生存していた。CAM染色法は、膜傷害作用機序をもつ抗菌成分の浸透殺菌をリアルタイムに観察する方法として有用であると思われた。(著者抄録)

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Language：Japanese   Publisher：(公財)8020推進財団  

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Language：Japanese   Publisher：新潟歯学会  

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Language：Japanese   Publisher：(一社)日本老年歯科医学会  

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Language：Japanese   Publisher：(一社)日本老年歯科医学会  

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Language：English   Publisher：新潟歯学会  

本研究は細菌間の間隙の少なさに注目した細菌塊形成の新しいモデル、言い換えれば、細菌同士が密着した細菌塊の形成モデル、を確立することを目的としている。Enterococcus faecalisあるいはPropionibacterium acnesの生菌をカバーグラス上に遠心によって付着させ、湿気を保って60分放置後、E.faecalisの場合72時間にわたって好気的に、P.acnesの場合5日間嫌気的に、1時間毎に25μlの培地を供給した。余分な培地は直ぐに滅菌した吸収紙を用いて除去し、遠心付着させた1層の細菌層の高さに培地が供給され、その中で細菌が増殖するようにした。60分間の放置中に細菌はカバーグラスに強く付着したと思われ、放置しなかった場合、容易に剥がれて洗い流された。この様にして形成された細菌塊は、遠心細菌塊や濾過細菌塊に比べ細菌密度が高く、細菌が密接して細菌間のスペースが無い状態で増殖し、その後、その上にまた密な細菌層を形成していると思われた。この様に密に形成された細菌塊は、細胞外に多糖体を形成しないにもかかわらず、いわゆる「バイフィルム」と同様、物質の浸透が極めて悪い状態にあると思われた。(著者抄録)

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Other Link： http://search.jamas.or.jp/link/ui/2011311847

Language：Japanese   Publisher：日本バイオフィルム学会  

バイオフィルム内部への高分子化合物の拡散能はバイオフィルムの発達、病原性発現および制御を考える上で重要な性質である。本研究では、人工バイオフィルム中への種々の高分子化合物(分子量376Daからの150kDaまでの蛍光物質および蛍光標識した多糖類、酵素、抗体)の浸透を共焦点レーザー顕微鏡を用いてリアルタイムに観察するとともに拡散係数を算出した。ガラスキャピラリーリアクターを用いて20時間培養することにより形成したStreptococcus oralis、Streptococcus gordonii、Actinomyces naeslundiiの三菌種混合人工バイオフィルム中央部への各種高分子化合物の浸透時間は、バイオフィルムの大きさ、および高分子化合物の分子量の増加とともに長くなる傾向が認められた。拡散係数は、純水に対して22%(IgG)から90%(dextran:3kDa)の範囲に減少し、相対的有効拡散係数は分子量の増加に伴って減少した。(著者抄録)

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Language：Japanese   Publisher：(一社)日本歯科審美学会  

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Language：Japanese   Publisher：(一社)日本老年歯科医学会  

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Language：Japanese   Publisher：(一社)日本老年歯科医学会  

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Language：Japanese   Publisher：(一社)日本老年歯科医学会  

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Language：Japanese   Publisher：(株)ヒョーロン・パブリッシャーズ  

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Language：Japanese   Publisher：(一社)日本歯科審美学会  

20代〜40代の歯学部学生および歯科研修医16名を被験者とし、新規歯面コーティング材「ビューティコート」の口腔内における経時的な色調変化を2週間にわたり観察するとともに、チッピングの頻度を調べた。さらに、被験者の感想をアンケート調査した。その結果、色調の変化はコート剤塗布後L*値とa*値が経時的に低下した。チッピングは10名13歯(全被験歯の14%)に認め、発生部位はいずれも切端部付近であり、固形物を切端部で噛み切ることで発生しているケースが多かった。アンケートの結果、使用感に関する項目(「味」「唇や歯肉の違和感」)について「気になる」と答えた人は1名(6%)のみであり、満足度は12名(75%)が「満足」と回答した。

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Language：Japanese   Publisher：日本バイオフィルム学会  

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Language：Japanese   Publisher：(株)デンタルダイヤモンド社  

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Language：Japanese   Publisher：(一社)日本老年歯科医学会  

近年、軽度の要介護高齢者の増加が厚生労働省より指摘され、平成18年度の介護保険制度の改正では、介護予防として口腔機能の向上が位置づけられた。また、平成20年度の「後期高齢者医療制度」では、食べる・話す・笑う機能を低下させないために「口腔機能の評価と管理」が位置づけられた。しかし、どちらも総合的な評価法や具体的な管理方法は、社会科学的施策として確立されていない。このような現状から、著者らは、自立から要介護までのすべての高齢者のための介護状態の予防・軽減、QOLの向上などを目指した安全で有効な口腔機能の評価と管理のシステムの開発を試行し、広く社会科学的に合理的な施策として実現すべく検討を試みてきた。今回はその第1報として、自立高齢者を対象に、口腔機能の総合的な検査法、その結果に基づいた改善法、その実施の有効性についての評価法を試行検討した。対象者は、札幌市の某ケアハウスに入所している自立高齢者91名である。口腔機能を総合的に評価するために、口腔の周り、口腔の入り口(咀嚼)、口腔の奥(嚥下)、口腔の清潔度の4つのカテゴリーに分けて行った。その結果を活用して改善法を提案・実施・評価を行った。その結果、咀嚼力の判定、唾液湿潤度検査、反復唾液嚥下テスト、オーラルディアドコキネシス、カンジダ検査が有意に改善したことにより、今回試作したシステムは、自立高齢者の口腔機能の評価と向上に役立つ可能性が示唆された。(著者抄録)

DOI： 10.11259/jsg1987.23.384

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Language：Japanese   Publisher：(一社)日本歯科審美学会  

新規歯面コーティング材ビューティコート(BC)を被験材料とし、質問票調査により審美性の評価を行った。表面滑沢材としてグロスエフェクトのみを用い、バフによる研磨は行わなかった。新潟大学医歯学総合病院受診患者および学生・研修医を対象とした。自分の歯の色が「気に入らない」との回答は対象者の半数以下であったが、調査対象者のほぼ全員が歯の色調改善を希望した。歯の色調を改善するために重要視する項目には回答者間に有意な一致性があり、「非侵襲性」が重要視される傾向を示し、「即効性」や「白さ」の平均順位は低かった。BCの審美性は主として「自然さ」の面で評価が分かれたが、非侵襲性への高い要求にはおおむね合致し、不快感が少なく好印象を与えうる審美効果が得られる材料であることが推察された。

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Language：Japanese   Publisher：(一社)日本歯科審美学会  

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Language：Japanese   Publisher：(一社)日本老年歯科医学会  

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Language：Japanese   Publisher：(一社)日本老年歯科医学会  

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Language：Japanese   Publisher：(公社)日本歯科医師会  

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Language：Japanese   Publisher：(公社)日本歯科医師会  

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Language：Japanese   Publisher：(一社)日本歯科審美学会  

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Language：Japanese   Publisher：日本歯内療法学会  

各種レジン系シーラーと固形根管充填材との界面に注目し、同部の封鎖性及び接着性について比較検討した。固形根管充填材としてResilon(R)、フレックスポイントネオ(F)及びガッタパーチャポイント(G)を、またシーラーとしてEpiphany(EP)、Superbondシーラー(SB)、シーラペックス(S)及びキャナルスN(C)を使用した。色素浸透試験において、実験群をEP/R群、SB/G群、SB/R群、SB/F群、コントロールとしてC/G群の5群(各n=5)を設定し、直径4mm、厚さ1mmのモールド内にシーラーを注入後、直ちにその中央にマスターポイントを挿入し、37℃浸潤下にて1週間保管した。その後、1%メチレンブルー5mlを試料表面に作用させ、1週間後に表面(色素接触面)および深さ1mmの位置(試料底面)での色素浸透を実体顕微鏡で観察しスコア評価した。その結果、深さ0mm面(色素接触面)では全ての試料間で有意差はなかった。一方、深さ1mm面の位置では、EP/R群は全例で色素浸透が認められなかった。SB/F群はEP/R群、SB/G群と比較して有意に大きいスコアを示した。次いで、接着強さの測定において、実験群をEP/G群、EP/R群、SB/G群、SB/R群、コントロールとしてS/G群、C/G群の計6群(各n=6)を設定し、#35のマスターポイント全周に厚さ2mmおよび5mmを一定体積のシーラーと接触させた状態で硬化させた試料を用い測定を行った。その結果、測定不能であったS/G群を除き、シーラー厚さ2mm,5mmの場合にEP/R群、SB/R群は各々EP/G群、SB/G群、C/G群と比較して有意に大きい測定値を示した。また、全ての群で2mmよりも5mmの方が有意に高い値を示した。

DOI： 10.20817/jeajournal.29.1_30

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Language：Japanese   Publisher：(NPO)日本歯科保存学会  

多機能性表面処理ガラスフィラー(Surface reaction type pre-reacted glass ionomer filler:以下,S-PRGフィラー)は,コンポジットレジンなどに配合することによりフッ素(F),ストロンチウム(Sr),ホウ素(B)などのさまざまな元素の徐放能を付与することが可能とされる.本研究では,新たに開発されたS-PRGフィラー含有試作根管充てん用シーラー(以下,S-PRGシーラー,松風)の諸性質を検討した.1.歯冠側における根管封鎖性の評価 ヒト抜去単根歯20本の歯根部を試料とし,#40/.06テーパーに拡大形成後,EDTA含有根管洗浄液(スメアクリーン,日本歯科薬品)を根管壁に作用させた.次いで無作為に4群(各n=5)に分け,S-PRGシーラー,もしくは酸化亜鉛ユージノール系シーラー(PulpDent Root Canal Sealer:以下,PulpDentシーラー)による糊剤根管充てん,もしくはガッタパーチャポイントを併用した側方加圧根管充てんを行った.試料を蒸留水中に60日保管後,0.2%フクシン溶液に24時間浸漬した後,歯根横断切片の実体顕微鏡観察を行い,根管口から根尖側1,3,5mmの位置での色素浸透を5段階のスコアで評価した.2.根管壁象牙質への各種イオンの取り込み観察 色素浸透試験と同様の方法で作製した試片を,蒸留水中に7あるいは60日間保管後,根管横断面の薄切片を作製し,根管壁におけるF,Sr,Bの分布を波長分散型エックス線マイクロアナライザーにより分析した.3.抗菌性の評価 Enterococcus faecalis,Propionibacterium acnesあるいはActinomyces israeliiが培養された血液寒天平板上に,S-PRGシーラーおよびPulpDentシーラー(いずれも練和直後および練和12時間後)を静置し,37℃,24時間嫌気培養後の阻止円の形成を観察した.これらの実験より,以下の結果が得られた.1.いずれの観察位置とも,色素浸透に4群間の有意差はみられなかった(Kruskal-Wallis検定,p&gt;0.05).2.S-PRGシーラーと接する根管壁象牙質に,FおよびSrの取り込みが確認された.PulpDentシーラーでは取り込みは観察されなかった.3.2種のシーラーは練和直後,練和12時間後ともP.acnesおよびA.israeliiに対し抗菌性を示した.E.faecalisに対する抗菌性は認められなかった.以上より,S-PRGシーラーがフッ素,ストロンチウム徐放能を備えること,および酸化亜鉛ユージノール系シーラーと同程度の根管封鎖性と抗菌性を示すことが示唆された.(著者抄録)

DOI： 10.11471/shikahozon.50.713

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Language：Japanese   Publisher：デンタルダイヤモンド社  

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Language：Japanese  

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Language：Japanese   Publisher：(一社)日本接着歯学会  

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Language：Japanese   Publisher：(一社)日本老年歯科医学会  

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Language：Japanese   Publisher：(一社)日本歯科審美学会  

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Language：Japanese   Publisher：(一社)日本老年歯科医学会  

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Language：Japanese   Publisher：(一社)日本歯科審美学会  

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Language：Japanese   Publisher：(NPO)日本歯科保存学会  

40本のエポキシレジン製透明湾曲根管模型(湾曲30°)に一定の規格でプレフレアリングを施した後,K3,ProTaper或いはEndoWaveを各種の使用順序や組合せで用いて根尖径が#30になるまで根管下部の形成を行い,根管形態を画像解析により分析した結果,以下の結論を得た.K3の使用順序を変更しても根管形態に影響はなく,内湾側よりも外湾側根管壁を多く切削したが,K3が内湾側の切削量は最も少なかった.ProTaperをK3又はEndoWaveと組み合わせて使用した場合,根管幅径増加量はK3又はEndoWave単独の場合とほぼ同程度であった.湾曲根管の形態変化は形成の最終段階での使用する1〜2本程度の器具に影響される面が大きいことが示唆された

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Language：Japanese  

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Language：Japanese  

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Language：Japanese   Publisher：(NPO)日本歯科保存学会  

フッ化ナトリウムと塩酸クロルヘキシジンの配合された歯磨剤(ジェルコート(F))をプラークの付着抑制効果の向上と知覚過敏防止を期待してNWEに混合し,これをホームブリーチングに用いた場合の口腔内環境に与える影響,知覚過敏の出現及び漂白効果について評価した.20歳代の学生30名の被験者をNWE単体群,NWE+ジョルコートF混合群,NWE+10%Carboxymethyl Cellulose群に10名づつに無作為に分けてブリーチングを2週間行い,その後の2週間目でも観察を行った.NWEとジェルコートFの併用によるホームブリーチング中はプラークの付着量と含そう水中の口腔内細菌数が減少傾向を示したが,ジェルコートFによる殺菌効果の増強は明らかではなかった.ジェルコートFの併用により知覚過敏の発生は抑制される傾向を示し,漂白効果の有意な低下はみられなかった.したがって,この併用方法は日常的な口腔ケアの方法として有用である可能性が示唆された

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Other Link： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2005&ichushi_jid=J01092&link_issn=&doc_id=20051108460018&doc_link_id=%2Fdo1conde%2F2005%2F004805%2F018%2F0751-0758%26dl%3D0&url=http%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fdo1conde%2F2005%2F004805%2F018%2F0751-0758%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

Language：Japanese   Publisher：(株)デンタルダイヤモンド社  

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Language：Japanese   Publisher：(一社)日本歯科審美学会  

規格支台より複製した模型を用いて,CEREC inLabシステムにより製作されたAluminaセラミッククラウンコーピングの適合性をセメントレプリカ法により検討した.直径10mmの真鍮棒を加工して製作した,高径の異なる3種の特注真鍮製支台を用いた.CEREC inLabシステムで製作したクラウンコーピングの規格支台より複製した模型との間隙量は辺録部で18.0〜39.0μm,内面部で59.5〜71.3μmであった.支台の高さ(2〜6mm)はアルミナクラウンコーピングの支台との間隙量に影響を与えなかった

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Language：Japanese   Publisher：(NPO)日本歯科保存学会  

フッ化物徐放性コンポジットレジン修復がエナメル質および象牙質窩縁部の歯質耐酸性に及ぼす影響を明らかにするため,走査型共焦点レーザー顕微鏡(LSM)を用い,人工脱灰後の脱灰深さの測定および微細構造学的観察を行った.フッ化物徐放性コンポジットレジン修復群では,従来型コンポジットレジン修復群と比較して,人工脱灰後の脱灰深さが有意に小さかった.従来型修復群では,脱灰は水平的に進行するとともに,接着界面で楔状の深い欠損が形成された.一方,フッ化物徐放型修復群では,接着界面近くでは小さく,離れると大きくなる曲線的な脱灰形態を示した.よって,フッ化物徐放性コンポジットレジンは,修復物辺縁歯質の耐酸性の向上に有効であることが示唆された

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Other Link： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2004&ichushi_jid=J01092&link_issn=&doc_id=20040901240001&doc_link_id=%2Fdo1conde%2F2004%2F004704%2F001%2F0529-0534%26dl%3D0&url=http%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fdo1conde%2F2004%2F004704%2F001%2F0529-0534%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

Language：Japanese   Publisher：(公社)日本歯科医師会  

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Language：Japanese   Publisher：(公社)日本歯科医師会  

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Language：Japanese   Publisher：(株)デンタルダイヤモンド社  

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Language：Japanese   Publisher：(株)ヒョーロン・パブリッシャーズ  

通常のホームブリーチングをホームケアとしての観点からその効果を明らかにすることを目的として,ブリーチング前後の口腔内細菌数の変化,歯垢の付着性,色調変化,歯面の形態的変化,歯髄反応,使用感等の口腔内環境への影響について総合的に検討した.ホームブリーチングにより口腔内細菌数の減少や歯垢の付着抑制効果が認められ,術前のPMTCや漂白効果による口腔管理意識の増加など,ホームケアへのモチベーションとしての効果が期待できた.しかし,エナメル質表層組織の粗造化,カルシウム溶出童の増加,知覚過敏,色の後戻り等の問題も既に指摘された

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Language：Japanese   Publisher：新潟歯学会  

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Language：English   Publisher：Niigata University  

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Language：Japanese   Publisher：(一社)日本老年歯科医学会  

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

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Language：Japanese   Publisher：(一社)日本老年歯科医学会  

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

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

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Language：English   Publisher：MUNKSGAARD INT PUBL LTD  

The aim of this study was to investigate acid resistance induced by starvation or biofilm formation in Streptococcus mutans ATCC 25175. The artificial biofilms were made on cover glasses, starved for 24 h and immersed in 0.1 M lactate buffer at pH 3.8 for 10 min. The biofilms were also exposed to 5% sucrose solution for 20 min to simulate acid shock produced by sucrose metabolism. Confocal laser scanning microscopy with fluorescein isothiocyanate staining measured the resultant minimum pH in biofilms. Live and dead organisms in biofilms were differentiated by confocal laser scanning microscopy with proidium iodide and SYTO9 staining. The same processes were used to treat planktonic organisms. The results showed that starved biofilms or planktonic cells showed significantly more viable bacteria after acid shock induced either by lactic acid or during sucrose consumption than non-starved biofilms or planktonic cells. In addition, biofilms showed greater resistance to acid shock induced by lactic acid than planktonic cells, whereas similar results were obtained where sucrose was used as a carbon source to reduce pH in biofilms and planktonic cells. Thus, it is suggested that starvation protects both biofilm and planktonic S. mutans from acid shock induced either by lactic acid or during sucrose consumption, while biofilm formation seemed to protect bacteria only from acid shock induced by pH 3.8 lactate buffer but not the acid shock of a slightly higher pH produced during sucrose consumption.

DOI： 10.1034/j.1399-302X.2001.160104.x

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Language：English   Publisher：Springer Japan  

Bacterial biofilms may be formed at various sites, including mucous membranes, teeth, and infectious lesions. To elucidate the structure and the function of biofilms, artificial biofilms of mucoid-type Pseudomonas aeruginosa organisms (strain PT1252) were made by centrifuging the organisms onto the surface of a coverglass and culturing further in broth media supplied continuously (45 ml/h). The biofilm structure at 4, 8, 12, and 24h was visualized with fluorescent staining (SYTO9, propidium iodide [PI], and/or fluorescein isothiocyanate-concanavalin A [FITC-ConA]) by confocal laser scanning microscopy (CLSM). It was clearly demonstrated that the number of bacteria (104-106/ml) could be estimated by their fluorescence intensity. Sectional analysis of each biofilm layer (1-μm thickness) made it possible to demonstrate the three-dimensional development of biofilms, and revealed that the biofilms were 9μm in height after 12h. The live and dead organisms were differentiated by SYTO9 and PI, respectively, in situ in biofilms, and about 13% of the organisms were dead in 12-h-old biofilms. When 12-h-old biofilms were exposed to ciprofloxacin at minimum bactericidal concentration (6.26μg/ml) for 90min, all the organisms were killed, but some organisms (11 ± 1.3%
n = 3) in 24-h-old biofilms with thicker and denser structure were still alive after exposure for 120min. These results indicate that the CLSM analysis of artificial biofilms was useful for elucidating bacterial functions in biofilms, and may lead to a new quantitative system for estimating the bactericidal efficacy of antibacterial drugs in biofilms.

DOI： 10.1007/s101560100014

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Language：English  

The present study investigated whether extracellular polysaccharides inhibit reaction between Streptococcus mutans and its specific immunoglobulin G (IgG) and penetration of the IgG through S. mutans biofilm. The planktonic organisms with or without extracellular polysaccharides were prepared, incubated with rabbit IgG against whole cell of S. mutans and fluorescein isothiocyanate (FITC)-conjugated goat affinity purified antibody to rabbit IgG. Biofilms with or without extracellular polysaccharides were formed on cover glasses and incubated with rabbit IgG against S. mutans and FITC-conjugated goat antibody to rabbit IgG. Then, biofilms were stained with propidium iodide. The amount of specific IgG binding on S. mutans was determined by FITC intensity with a fluorescence microplate reader. The penetration of IgG through biofilms was determined by confocal laser scanning microscopy. The results showed that the fluorescence intensity of FITC in planktonic organisms with extracellular polysaccharides was similar to that in planktonic organisms without extracellular polysaccharides, indicating that extracellular polysaccharides did not inhibit the reaction between S. mutans and its specific IgG. Although biofilms of S. mutans with extracellular polysaccharides were much thicker and denser than those without extracellular polysaccharides, the speed with which IgG penetrated through both of the biofilms did not differ significantly, suggesting that penetration of IgG through S. mutans biofilm was not affected by extracellular polysaccharides.

DOI： 10.1034/j.1399-302X.2001.160109.x

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：AMER ASSOC DENTAL RESEARCH  

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Language：Japanese   Publisher：Niigata University  

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：AMER ASSOC DENTAL RESEARCH  

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Language：Japanese   Publisher：新潟歯学会  

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Presentation type：Public lecture, seminar, tutorial, course, or other speech  

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Language：English   Presentation type：Symposium, workshop panel (nominated)  

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Language：English   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

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Language：English   Presentation type：Symposium, workshop panel (nominated)  

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