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The aim of this study was to assess the possibility of digital image analysis of pit-and-fissure discoloration in order to diagnose caries. Digital images showing pit-and-fissure discoloration in 100 teeth of 19 patients were analyzed to obtain the fractal dimension (FD) and the proportion of the area of pit-and-fissure discoloration to the area of occlusal surface (PA). DIAGNOdent values were measured (DD), and dentists' diagnoses were also obtained. The sensitivity and specificity of FD, PA, DD, and the combination of FD and PA compared to the dentists' diagnoses were calculated. The sensitivities of FD, PA, DD, and the combination of FD and PA were 0.89, 0.47, 0.69, and 0.86, respectively, and the specificities were 0.84, 0.95, 0.91, and 0.86, respectively. Although further research is needed for the practical use, it is possible to use the analysis of digital images of pit-and-fissure molar discoloration as a diagnostic tool.

Objective: Secondhand smoke (SHS) is considered a risk factor for a number of oral diseases. However, its influence on tooth loss, which is the final consequence of periodontal disease and caries, remains unknown. We aimed to evaluate the association between SHS experience and the number of remaining teeth among non-smoking older Japanese individuals. Methods: Cross-sectional data from the Japan Gerontological Evaluation Study (JAGES) 2013 were used. From the 27,561 people ≥65 years of age who responded to a self-reported questionnaire (response rate = 71.1%), data of 18,865 respondents who had never smoked were analysed. Multinomial logistic regression with multiple imputations was applied to estimate the odds ratio of the frequency of SHS exposures on the number of remaining teeth. Results: The prevalence of participants with ≥20 teeth, 10-19 teeth, 5-9 teeth, 1-4 teeth, and no teeth were 53.2%, 20.4%, 9.9%, 6.6%, and 9.9%, respectively. The proportion of participants with SHS was 37.5%. After adjusting for sex, the SHS experience tended to be associated with a lower risk of having the fewer number of remaining teeth (P < 0.05). However, after being adjusted for age and sex, participants with SHS exposure at "a few times a week" and "almost every day" were significantly associated with the fewer number of teeth. After adding all other covariates, compared to the participants without any exposure to SHS, the odds ratio for having no teeth rather than having ≥20 teeth among the participants with daily exposure to SHS was 1.35 (P < 0.01). Conclusion: Daily secondhand smoke was significantly associated with fewer remaining teeth based on the self-reported survey among older Japanese people.

Background: The relationship between dental anxiety and mucosal wound healing, especially the inflammatory response, has not been well studied. This study aimed to examine the relationship between anxiety prior to dental treatment and short-term inflammation following impacted mandibular third molar (IMTM) surgery. Methods: Fifty-nine patients who required IMTM surgery were recruited for this study. Sample demographics (gender, age) and surgical extent (Pederson classification, duration) were collected. Psychological stress towards surgery was assessed by the Dental Fear Survey (DFS). All surgeries were conducted according to an identical surgical protocol and all patients were given the same medical prescription. Correlations between short-term inflammation (swelling and trismus after 2 days) and DFS, demographics and surgical extent were statistically analysed. Results: The results showed that patients with a higher DFS score demonstrated more severe swelling (b = 0.36, P = 0.016) and trismus (b = 0.37, P = 0.008) 2 days after surgery. In addition, more severe trismus occurred following more difficult surgery (b = 0.29, P = 0.016) or that with a longer duration (b = 0.21, P = 0.081). Neither gender nor age showed any significant relationship with swelling or trismus. Conclusion: Short-term inflammatory response following IMTM surgery correlated with the preoperative dental anxiety and this correlation was independent of gender and surgical extent.

Purpose:The rapid deterioration of oral health in young adults is an alarming problem in Japan. The aim of the present study is to investigate the oral health status, subjective oral symptoms and oral health behaviors of dental students. Methods: Participants were 108 first-year students attending dental school in 2018-2019. Oral examinations were performed to assess dental caries indices, oral hygiene status, gingival bleeding on probing (BOP) and pocket depth. A self-administered questionnaire was used to assess subjective oral symptoms and oral health behaviors. Results: The prevalence of decayed teeth (DT) and gingivitis (BOP ≥ 10%) were 43.5% and 50.0%, respectively. Having DT and gingivitis were significantly associated with poorer oral hygiene. No association was observed between DT and subjective symptoms. Having gingivitis was significantly associated with xerostomia, mouth-breathing and less use of interdental cleaning tools. Multiple logistic regression analysis for gingivitis yielded an odds ratio of 1.41 (95% confidence interval: 1.19-1.67) for plaque score, and 2.75 (1.27-5.98) for xerostomia. Conclusion: Since a relatively high ratio of students had DT and gingivitis without clear subjective symptoms, they require regular dental visits for early treatment and oral hygiene maintenance from the start of their time at university.