This study was conducted to compare subjective and objective assessment methods of a two-colored chewing gum test and to find out whether these methods are capable of discriminating masticatory performances between sexes. 31 adults, 16 males and 15 females participated in this study. Each subject chewed five samples of two-colored chewing gum sticks for 5, 10, 20, 30 and 50 chewing strokes, respectively. The subjective color-mixing and shape indices for the gum bolus (SCMI-B, SSI-B) and the subjective color-mixing index and objective color-mixing ratio for the gum wafer (SCMI-W, OCMR-W) were evaluated by two independent examiners and, on a different day, re-evaluated by one of the examiners. The SCMI-B and SCMI-W assessments had inter- and intra-examiner reliable agreement at 20 or more chewing strokes. The OCMR-W measurement demonstrated high accuracy and low reproducibility between and within the examiners. There were significant gender differences in the distribution of SCMI-W scores (P = 0.044) and in the mean OCMI-W (P = 0.007). The SCMI-B and SCMI-W assessments and the OCMR-W measurement were reliable and valid at the 20 and 30 chewing strokes in this two-colored chewing gum test. The subjective color-mixing index (SCMI-W) and objective color-mixing ratio (OCMR-W) for the chewing gum wafer are capable of discriminating masticatory performance between sexes in this two-colored chewing gum test and that the OCMR-W measurement is discriminating better than the SCMI-W assessment.

The aim of this study was to explore the patterns of tooth agenesis in Japanese orthodontic patients with bilateral agenesis of mandibular second premolars. A total of 80 Japanese orthodontic patients with 2 congenitally missing mandibular second premolars were selected as the subjects of this study (experimental group). Another 80 individuals without bilateral agenesis of mandibular second premolars were collected for comparison (control group). The 2 groups were matched with regard to sex. Radiographs, dental casts and records of medical and/or dental treatment were used to identify tooth agenesis. The Chi-square test, odds ratio, and test for equality were used to make statistical comparisons. The prevalence rates of other types of tooth agenesis were significantly higher in the experimental group than in the control group. The occurrence of agenesis of maxillary and mandibular lateral incisors and third molars, and maxillary second premolars was also significantly higher in the experimental group than in the control group. Significantly increased prevalence rates of symmetrical tooth agenesis, with third molars included, and oligodontia were observed in the experimental group. Japanese subjects with bilateral agenesis of mandibular second premolars are at significantly high risk of agenesis of other types of permanent teeth, symmetrical tooth agenesis and oligodontia.

This study was conducted to assess the usefulness of thermography for quantifying facial temperature before and after orthognathic surgery and intermaxillary fixation, and the effects of these orthognathic procedures on facial temperature. Facial thermograms of 10 patients who underwent bilateral sagittal split ramus osteotomy (SSRO, one-jaw group) and another 10 patients who underwent Le Fort I osteotomy and bilateral SSRO (two-jaw group) were taken 1 day before orthognathic surgery (T1) and at release of intermaxillary fixation 7 days later (T2). Two thermograms taken 30 s (TG1) and 3 min (TG2) after the start of recording at T1 and T2 were used. A square (26 × 26 pixels) was marked on each thermogram and the mean facial temperature for each square was measured. Three-way analysis of variance was used for statistical comparisons. Facial temperatures were significantly higher at T2 than at T1 on TG1 and TG2, and were significantly higher on TG2 than on TG1 at T1 and T2. The two-jaw group had a significantly higher facial temperature than the one-jaw group. Thermography was useful for quantitative assessment of facial temperature in patients undergoing orthognathic surgery. Changes in facial temperature were due predominantly to inflammation after surgery, rather than to sarcopenia.

Stress is a risk factor for numerous lifestyle diseases, including dental diseases. The purpose of the present study was to investigate how sensitivity to psychological stress relates to subjective symptoms and regular hospital visits using information from the large-scale database of national statistics. Anonymized data from 10,584 respondents aged 30–79 of the Japanese 2013 Comprehensive Survey of Living Conditions were analyzed. Respondents were classified by age into a middle-aged group and an elderly group, and a contingency table analysis, rank correlation analysis, and binomial logistic regression analysis were performed. Contingency table analysis confirmed that eight items were related to the presence of a recognition of stress, including the presence of subjective symptoms (p < 0.001), the presence of regular hospital visits (p < 0.001), symptoms of periodontal disease (p < 0.001), and self-rated health (p < 0.001). Responses for symptoms and diseases requiring regular hospital visits were ranked in order for a stress group and a no stress group, and it was found that other than fatigue symptoms being ranked highly in the stress group, there were no particular differences. Logistic regression analysis results showed significant odds ratios for six items including: self-rated health (3.91, 95% CI, 3.23 to 4.73), lifestyle awareness (1.96, 95% CI, 1.68 to 2.28), and symptoms of periodontal disease (1.71, 95% CI 1.19 to 2.48). The present study showed that susceptibility to psychological stress is related to awareness of subjective symptoms and to regular hospital visits due to disease, suggesting that these have direct and indirect mutual effects.

Objective:The purpose of this study was to assess the effects of long-term repeated topical application of fluoride before bonding and an adhesion promoter on the bond strength of orthodontic brackets.Materials and Methods:A total of 76 bovine incisors were collected and divided equally into four groups. In group 1, the brackets were bonded without topical fluoride application or adhesion promoter. In group 2, before bonding, the adhesion promoter was applied to nonfluoridated enamel. In group 3, the brackets were bonded without the application of the adhesion promoter to enamel, which had undergone long-term repeated topical fluoride treatments. Teeth in group 4 received the long-term repeated topical applications of fluoride, and the brackets were bonded using the adhesion promoter. All the brackets were bonded using BeautyOrtho Bond self-etching adhesive. The shear bond strength was measured and the bond failure modes were evaluated with the use of the adhesive remnant index (ARI) after debonding.Results:The mean shear bond strength was significantly lower in group 3 than in groups 1, 2, and 4, and there were no significant differences between the groups except for group 3. There were significant differences in the distribution of ARI scores between groups 2 and 3, and between groups 3 and 4.Conclusions:The adhesion promoter can recover the bond strength reduced by the long-term repeated topical applications of fluoride to the prefluoridation level and had a significantly great amount of adhesives left on either fluoridated or nonfluoridated enamel.