Phenolic compounds in fruits such as cranberries have been shown to promote a number of biological activities. The purpose of this study was to investigate the effects of polyphenolic compound-containing lingonberry extract on oral streptococci and compare them with the known anti-cariogenic activity of cranberries. Water-soluble and polyphenol-rich fractions (Fractions I and II, respectively) were isolated from cranberries and lingonberries. The effects of those fractions on the biofilm formation ability and bioactivity of Streptococcus mutans MT8148R, Streptococcus sobrinus 6715, and Streptococcus sanguinis ATCC 10556 were then evaluated. Cranberry or lingonberry Fraction II (at 0.5–1 mg/ml) significantly reduced biofilm formation by S. mutans, S. sobrinus, and S. sanguinis. In contrast, cranberry or lingonberry Fraction I (at 0.5–2 mg/ml) increased biofilm formation by S. mutans and S. sobrinus, but not by S. sanguinis. Fractions I and II (at 1–2 mg/ml) also reduced the bioactivity of S. mutans, while Fraction II (at 0.5 mg/ml) enhanced the bioactivity of all tested strains. The results revealed that lingonberries contained a larger amount of polyphenol than cranberries and that they showed almost the same level of activity against the biofilm formation ability and bioactivity of oral streptococci. This indicates that polyphenol-rich lingonberry fraction offers a promising natural food derivative for prevention of dental caries.

To our knowledge, this is the first study to investigate the thickness of the normal epiglottis on computed tomography (CT) in a Japanese population. The focus was on determining the thickness of a normal epiglottis, which could then serve as a reference in detecting abnormalities. We believe that this would facilitate diagnosing and determining the extent of cancerous invasion of the supraglottis and secondary invasion of the epiglottis. This retrospective study was based on a review of radiographic data in patient charts. Cervical CT scans obtained from 79 Japanese patients (44 men [55.7%] and 35 women [44.3%]; age range, 28–85 years; mean, 58.9 years) showing a normal epiglottis under laryngoscopy were evaluated. The thickness of the epiglottis was measured on CT scans and the results analyzed with the Student's t-test, an analysis of variance, and the Tukey-Kramer test. The epiglottis in men was significantly thicker than that in women (p<0.05). A statistically significant difference was observed in thickness depending on longitudinal height (p=<0.001). The thickness at the median was larger than that bilaterally in all patients (p=<0.001). No statistically significant difference was observed in thickness depending on side or age. The thickness of the normal epiglottis was established at each level. We believe that these data could serve as a reference in diagnosing and detecting abnormalities of the epiglottis.

The purpose of this study was to investigate the influence of differences in axial thickness and type of cement on fracture load in CAD/CAM crowns. Assuming the mandibular first premolar to be the abutment tooth, 4 types of crown with different axial thicknesses and radii of curvature were prepared. To unify external design, the morphology of the crown margins was set at 0.15, 0.30, 0.45, or 0.60 mm, thus maintaining uniform axial form of the crowns. The CAD/CAM crowns and abutment teeth were bonded using each of 2 types of resin cement or polycarboxylate cement. The fracture load value was measured using a universal testing machine and the destruction phase observed.

No significant difference was observed with change in axial thickness. The fracture load values with each of the 2 types of resin cement used were significantly higher than that with polycarboxylate cement (p<0.01). These results suggest that the fracture load values of CAD/CAM crowns are not influenced by differences in the axial thickness of the crown, and that they are higher when bonding is achieved with resin rather than polycarboxylate cement.

Oral exfoliative cytology is now used by general practitioners in Japan to screen for oral cancer. With conventional cytology, however, the number of cells that can be sampled is small. Moreover, cell deformation and piling of cells when preparing specimens has been reported. The purpose of this study was to compare conventional and liquid based cytology (LBC), which has been employed with increasing frequency in recent years. We believe that identifying potential pitfalls in oral exfoliative cytology will help improve diagnostic accuracy. A total of 153 patients with tongue squamous cell carcinoma who were diagnosed and treated initially at our hospital between January 2000 and December 2010 were included. Of these, 124 underwent conventional cytology, while the remaining 29 underwent LBC. Histopathological and clinical findings were used as criteria. Conventional cytology yielded a positive rate of 54.8% and LBC 79.3%, while values of 28.2% and 13.8% were obtained for a suspected positive rate, respectively. Liquid based cytology yielded a significantly higher percentage of accurate diagnoses and fewer suspected positives (p<0.05) in cases clinically classified as endophytic and those classified as ulcerative in terms of clinical growth pattern. No significant difference was observed between conventional cytology and LBC in cases of an infiltrative growth pattern, however.

The present results suggest that LBC is superior to conventional cytology in achieving an accurate diagnosis based on oral exfoliative cytology. The present findings also suggest that exophytic type, and especially leukoderma type clinical growth patterns constitute pitfall cases in oral exfoliative cytology.

The goal of this study was to investigate how the height of the archwire hook and implant anchor affect tooth movement, stress in the teeth and alveolar bone, and the center of resistance during retraction of the entire maxillary dentition using a multibracket system. Computed tomography was used to scan a dried adult human skull with normal occlusion. Three-dimensional models of the maxillary bone, teeth, brackets, archwire, hook, and implant anchor were created and used for finite element analysis. The heights of the hook and the implant anchor were set at 0, 5, or 10 mm from the archwire. Orthodontic force of 4.9 N was systematically applied between the hook and the implant anchor and differential stress distributions and tooth movements observed for each traction condition. With horizontal traction, the archwire showed deformation in the superior direction anterior to the hook and in the inferior direction posterior to the hook. Differences in traction height and direction resulted in different degrees of deformation, with biphasic movement clearly evident both in front of and behind the hook. With horizontal traction of the hook at a height of 0 mm, all the teeth moved distally, but not with any other type of traction. At a height of 5 mm or 10 mm, deformation showed an increase. The central incisor showed extrusion under all traction conditions, with the amount showing a reduction as the height of horizontal or posterosuperior traction increased. The center of resistance was located at the root of the 6 anterior teeth and entire maxillary dentition. The present results suggest that it is necessary to consider deformation of the wire and the center of resistance during en-masse retraction with implant anchorage.

The purpose of this study was to survey parental satisfaction with ambulatory anesthesia during dental treatment in disabled patients. Factors associated with parental preference for general anesthesia during future dental treatment in such patients were also investigated. A questionnaire was mailed to the parents of 181 disabled individuals who underwent dental treatment under ambulatory anesthesia at Tokyo Dental College Suidobashi Hospital between 2012 and 2016. A total of 71 responses were received (39.2%). The mean patient age was 18 years, and disabilities included autism spectrum disorder, intellectual disability, cerebral palsy, and epilepsy. The items surveyed included dental treatment details, number of times patients received general anesthesia, type of anesthetic used, anesthesia induction method, durations of treatment and anesthesia, and the presence or absence of intraoperative or postoperative complications. Questionnaire items queried problems related to dental care, anesthesia history, preoperative anxiety, length of fasting period, induction of general anesthesia, nursing and hospital room environment, postoperative anxiety, overall evaluation, and whether the parent would prefer general anesthesia during future dental treatment. The patients were divided into 2 groups: those whose parents preferred general anesthesia during future dental treatment and those whose parents did not. The results revealed that, where disabled individuals had previously received general anesthesia during dental treatment, the parents were more likely to prefer general anesthesia during future dental treatment.

Candida albicans, one of the main pathogens in the oral cavity, is involved in the development of oral candidiasis. Various components of tea, and especially polyphenols, are believed to be effective against the growth of yeast or bacteria. The purpose of this study was to investigate the effect of polyphenols in Mongolian herbal tea on growth of C. albicans. Tea extract was prepared from Mongolian herbal tea and diluted with distilled water (DW) at concentrations of 10, 20, 30, 40, or 50%. Distilled water was used as the control. Acidification of the medium was determined by measuring its pH; the presence of polyphenols by the Folin-Ciocalteau colorimetric method; and growth of C. albicans by absorbance at a wavelength of 630 nm at 0-, 6-, 12-, and 24-hr intervals. The pH of the medium was 5.2 to 5.27 in all experimental groups compared with 7.1 in the control group. Polyphenols were present in all experimental groups, and at significantly higher levels than in the control group. Growth of C. albicans showed a significant and time-dependent increase in the control and all experimental groups. Growth of C. albicans in all the experimental groups was higher than that in the control group. These results suggest that Mongolian herbal tea promotes the growth of C. albicans, despite the presence of polyphenols.