Abstract in Japaneses

 Recently, the number of reports on the association between sarcopenia and the oral function has been increasing. However, in previous studies, few aspects of the oral condition, including oral function and number of teeth present, were examined in association with sarcopenia. Furthermore, there is a lack of consistency across studies, and the detailed associations have not been clarified. The aim of this study was to investigate the association between various aspects of the oral condition, including oral function, and sarcopenia in older adults.

 Patients aged 60 or over who visited the Department of Preventive Dentistry at Okayama University Hospital between October 2022 and June 2023 participated in this cross-sectional study. Sarcopenia, the oral condition, nutritional status, mental and psychological status, and comorbidities were recorded. For the oral condition, the bacterial count on the tongue dorsum, oral wettability, tongue pressure, tongue and lip movement function (oral diadochokinesis [ODK]), masticatory ability, bite force, and swallowing function were measured. The nutritional status was assessed using Mini Nutritional Assessment (MNA). Mental and psychological statuses were assessed using Geriatric Depression Scale. Based on χ² and Mann-Whitney U tests, age, sex, tongue pressure, ODK for /pa/ and /ka/, number of teeth present, and MNA score were associated with sarcopenia. The results of covariance structural analysis showed that: high tongue pressure was associated with good nutritional status, good nutritional status was associated with non-sarcopenia, and age was associated with tongue pressure, nutritional status, and sarcopenia.

 In conclusion, tongue pressure was associated with the nutritional status, and the nutritional status was associated with sarcopenia. The results suggest that a decrease in tongue pressure may lead to worsening of the nutritional status, which may cause sarcopenia.

 This study aimed to develop a task-specific self-efficacy scale for self-care (SESS) for orthodontic treatment and verify its reliability and validity. In a preliminary survey, a draft SESS consisting of 47 items was designed and applied to 52 patients who receive orthodontic treatment. Based on the item analysis, 16 items were selected for the SESS. A main survey was conducted on 83 patients who receive orthodontic treatment in order to verify the reliability and validity of the SESS. Based on the factor analysis, three factors were extracted: “self-efficacy for tooth brushing”, “self-efficacy for habituation”, and “self-efficacy for snacking and check-up”. The SESS showed sufficient internal consistency (Cronbach’s alpha=0.89). There was a significant association between the test and re-test (ρ=0.73, p<0.001) and the SESS showed high reliability. The SESS was significantly associated with the general self-efficacy scale (ρ=0.23, p=0.037) and showed concurrent validity. There was no significant difference in the mean change in dental plaque score from before to after the setting of orthodontic instruments between the high and low SESS score groups. Thus, the SESS exhibited no predictive validity. Viewed collectively, our SESS showed high reliability and concurrent validity in orthodontic treatment. Future clinical studies using our SESS are expected.

 The purpose of this study was to evaluate the usefulness of the motivation scale score (MSS) for Japanese adults and investigate motivation related to the oral condition on receiving basic periodontal therapy using MSS.

 The participants enrolled in this study were 221 patients with periodontal disease aged 20-64 years who visited a dental clinic in Shizuoka City, Japan for the first time. MSS was calculated using a 14-item-questionnaire concerning the patients’ motivation assessment scale, and principal component analysis of MSS was performed. The associations among MSS, items of oral health behavior, periodontal conditions [Bleeding on probing (BOP) rate, Periodontal inflamed surface area (PISA)], and oral hygiene status [O’Leary’s Plaque control record (PCR)] were evaluated at the baseline and after basic periodontal treatment.

 MSS was shown to be useful in terms of reliability and validity and was classified into five factors. MSS and MSS-Factor 1 (oral hygiene practices) of participants with BOP of less than 10% were significantly higher than in of participants with BOP of more than 10% at the baseline. In addition, MSS and MSS-F1 were significantly higher among participants who received regular dental check-ups within a year and used interdental cleaning tools. MSS-F1 was significantly higher in non-smokers. By binominal logistic regression analysis, the use of interdental cleaning tools was significantly correlated with BOP of less than 10% at the baseline. All items related to oral conditions and oral health behavior improved after basic periodontal therapy, except for current smoking status. After basic periodontal therapy, MSS was significantly higher in participants with PCR of less than 20%, and MSS-F1 was significantly higher in participants who used interdental cleaning tools or were non-smokers.

 It was revealed that MSS used in this study was useful and associated with the periodontal condition and oral health behavior at the baseline. The values of MSS and MSS-F1 significantly increased after basic periodontal therapy. The use of interdental cleaning tools was associated with a good oral condition and higher MSS. Therefore, high motivation might lead to a good oral condition in patients with periodontal disease through the use of interdental cleaning tools by influencing patients’ compliance to improve their oral health behaviors.

 Dental caries is the most common disease of the human mouth. Streptococcus mutans is a major cariogenic bacterium. Hinokitiol (HNK), a natural substance extracted from plants such as Chamaecyparis obtusa var., is known for its antibacterial and antifungal properties. Although the antibacterial effect of HNK against periodontal bacteria and fungi has been studied in detail, little is known about its antibacterial effect on cariogenic bacteria, specifically S. mutans. The purpose of this study was to investigate the antibacterial activity of HNK against S. mutans, and evaluate its potential as a preventive agent against cariogenic diseases. HNK marked remarkable antimicrobial activity against cariogenic bacteria. Moreover, it also inhibits the formation of S. mutans biofilms and exhibits bactericidal activity within the biofilms. Furthermore, HNK can inhibit key virulence factors of S. mutans associated with cariogenicity. In conclusion, HNK may be a new agent with anticariogenic potential not solely via inhibition of the growth of cariogenic bacteria.