[in Japanese]

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Japan is considered a super-aged society. Thus, high-quality denture treatment is important to the quality of life (QOL) in elderly patients. During denture adjustment, patients may have to wait in the chair (blank time) while the dentist adjusts and polishes the denture. The purpose of this study was to investigate methods to achieve efficient and high-quality treatment. This investigation was executed in two ways：firstly through an evaluation of treatment content and chair time of denture adjustment, and secondly through an attitude survey of dentists, patients, and treatment assistants. Three groups of subjects were included in this study：edentulous patients with upper and lower complete dentures (n＝31), their dentists (n＝14), and dental assistants (n＝12). The patients provided informed consent to participate in this study. As a first step, the entire treatment procedure was recorded on video. After treatment, each item of the evaluation survey was completed. The time for each treatment step was calculated from the recorded video. The relationship between questionnaire response and blank time was evaluated by independent t-test using SPSS statistical software (PASW Statistics Base 18, IBM, and Tokyo, Japan). The mean chair time was 28.0 (±11.8) min. Patientsʼ blank time was 47% and assistantsʼ blank time was 45%, relative to the chair time. However, the dentistsʼ blank time was only 4% of the chair time. The patients and assistants marked high scores for the questionnaire with no correlation between the blank time or chair time and treatment evaluation. However, the dentists were conscious of the blank time experienced by the patients and assistants, and the questionnaire scores marked by the dentists were lower as the blank time was longer. Dentists and assistants should recognize the importance of patientsʼ and assistantsʼ blank time and utilize this blank time effectively in order to provide more efficient and higher quality treatment.

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Retention and stability are important considerations for successful complete denture treatment. A compact device to measure denture retention has been developed by Aoyagi et al. Therefore, the aim of this study was to identify the optimal sites and loading methods for the evaluation of retention with this device. This study included 30 subjects with edentulous maxillae. Dentures were coated using jigs made from a thermoplastic resin to protect and pull the denture. The pulling test was performed at the central point of the posterior border (P), intersection point of the line joining the right and left first molar central fovea (C), and left first molar central fovea (MF). The pushing test was performed at the central point of the central incisor edge (IE) and right first premolar buccal cusp (PC). Each site was measured five times, and the retention forces for detachment of the denture were determined. However, measurement was discontinued at 30 N because the subjects reported pain. A site was considered immeasurable if it could not be measured twice in succession. Two-way ANOVA, Tukeyʼs multiple comparison tests, and Pearsonʼs correlation analysis were used for statistical analysis. The C and MF sites were immeasurable in approximately 50% of the subjects. The P, IE, and PC sites were measured in all subjects. P and IE showed no significant differences. However, PC was significantly higher than P and IE (p＜0.01). A positive correlation was observed between P and IE (r＝0.640, p＜0.01) and between P and PC (r＝0.452, p＜0.05). IE showed a strong positive correlation with P and reproducible measurements of denture retention. Therefore, the optimal loading method and site was the pushing test of IE without the jig.

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The purpose of this study is to clarify how an oral function improvement program could contribute to the cognitive function of the elderly persons in a group home. The Subjects comprised 36 elderly persons (mean age 86.1±5.2 years) living in a group home in Kagoshima Prefecture (GH-A) or in Kanagawa Prefecture（GH-B）. The cognitive function was evaluated by used with mini-mental statement examination (MMSE), and subjects MMSE score of ten or more were selected. The oral functions were assessed in 4 categories (oral myofunctional activity, mastication, swallowing and oral cleanliness). As for attendance in the oral function improvement program (PR), most of the subjects in GH-A had come in the PR, but in GH-B, 40% of subjects had it (p＜0.01). The items of PR that they had used were similar with both homes. After 6 months, the oral function increased significantly with RSST and with oral diadochokinesis “pa” sound in GH-A. In addition, the masticatory ability with XYTOL^® increased significantly in GH-A. In the cognitive function, the MMSE score did not decrease with GH-A after one year, but it decreased significantly with GH-B. From these results, it was suggested that the oral function improvement program can restrain the decline of MMSE score and contribute to the cognitive function.

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