OBJECTIVE: Although poor oral health has been a potentially modifiable risk for mortality, the precise association between functional tooth units (FTUs) and premature death as well as the underlying mechanisms remains unclear.
METHODS: This study used data from the National Health and Nutrition Examination Survey (NHANES) 2009-2018. Mortality details were obtained from the National Death Index (NDI). The number of FTUs was defined as pairs of opposing natural and artificial teeth in the premolar and molar area. Weighted logistic regression models were employed to assess the relationship between FTU and premature death. Demographic characteristics, lifestyle habits, and disease histories were adjusted as confounding factors. The propensity score matching (PSM) was conducted to further assess the association between FTU and premature death. Mediation analyses were conducted to assess the role of diet-related diseases in the association between FTU and premature death.
RESULTS: The analysis included 4169 individuals aged between 60 and 74 years. Participants with 0 ≤ FTUs ≤ 3 had a significantly higher odds of premature death compared to the 10 ≤ FTUs ≤ 12 group (OR = 2.142, 95% CI 1.091-4.208). After missing data imputation, 0 ≤ FTUs ≤ 3 was still significantly associated with increased odds of premature death (OR = 2.115, 95% CI 1.125-3.975). The relationship between 0 ≤ FTUs ≤ 3 and reference group persisted (OR = 2.196, 95% CI 1.296-3.721) after PSM analyses. For mechanism, mediation analysis showed that diet-related diseases, including diabetes and hypertension, partially mediated the association between FTU and premature death with proportions of 5.089% and 8.437%, respectively.
CONCLUSIONS: The findings revealed a link between impairment of masticatory function and a heightened odds of premature death among older adults. Notably, 0 ≤ FTUs ≤ 3 is significantly correlated to premature death among this demographic, with diabetes and hypertension partially mediating the effect of FTU on premature death. Further longitudinal studies are required to validate the findings.

OBJECTIVE: This pilot study evaluated the relationships between appetite and oral function, and between appetite and the subjective symptoms of decreased oral function.
METHODS: Seventy-one adult dental clinic patients (22 males, 66.0 ± 14.0 years) participated in this study. A Council on Nutrition Appetite Questionnaire score of ≤28 indicated anorexia, and the Mini Nutritional Assessment Short-form, body mass index and skeletal muscle mass index were used to define subject characteristics. Seven oral function tests and seven subjective symptoms related to oral function were evaluated. The relationship between subject characteristics, oral function tests, subjective symptoms and anorexia was analysed using the chi-square test and univariate and multivariate logistic regression.
RESULTS: There were significant differences between the normal appetite group and the anorexia group for the 10-item Eating Assessment Tool (EAT-10) survey and the question \'Food remains in the oral cavity after eating\' (p < .05). Univariate logistic regression found significant differences in the items of masticatory function, the EAT-10 survey and the question \'Food remains in the oral cavity after eating\'. Multivariate logistic regression revealed significant differences in masticatory function (AOR 4.35; 95% CI: 1.03-18.35; p = .045) and EAT-10 (AOR 6.27; 95% CI: 1.40-24.02; p = .016).
CONCLUSIONS: This pilot study investigated the influence of factors related to oral function on appetite. Relationships were found among poor masticatory function, poor swallowing function and anorexia.

UNASSIGNED: In cases of missing posterior teeth, treatment modalities based on the shortened dental arch (SDA) concept may be a viable alternative. However, the association between oral health-related quality of life (OHRQoL) and patients\' treatment decisions remains unclear. This study aimed to investigate the association between OHRQoL and the decision to be treated with implant-supported fixed partial dentures (IFPDs) or take a wait-and-see approach in patients with an SDA missing a single second molar and to clarify the impact of IFPD treatment on the OHRQoL.
UNASSIGNED: The Oral Health Impact Profile (OHIP) questionnaire was administered twice (pre- and post-treatment) and once to 41 patients with a unilateral SDA missing a single second molar who chose IFPD treatment (IFPD group, n = 22) and the wait-and-see approach (no treatment group, n = 19), respectively. Logistic regression analysis was performed with IFPD treatment choice as the objective variable and the four OHIP dimension scores, age, and sex as covariates. The pre- and post-treatment values of the OHIP summary and four-dimension scores were compared using a paired t-test.
UNASSIGNED: The IFPD treatment choice was significantly associated with sex (male), higher Oral Function dimension scores, and lower Psychosocial Impact dimension scores (all P < 0.05). The OHIP summary and four-dimension scores were significantly lower following IFPD treatment (all P < 0.05).
UNASSIGNED: IFPD treatment for a single missing second molar may be clinically beneficial for improving the OHRQoL of patients with an SDA who experience a decline in masticatory function.

As we age, maintaining good oral health becomes increasingly crucial for performing daily tasks. Age-related physiological decline can disrupt various biological systems, causing a significant challenge for geriatric dentistry. A systematic review of the literature using six different electronic databases was conducted to investigate the relationship between oral health indicators and bone mineral density disorders in older adults. The study is registered as a priori protocol on PROSPERO (CRD42023403340). A minimum age of 60 years was the main inclusion criterion for all original research articles. Two independent researchers assessed the eligibility of 19,362 records against the inclusion criteria and found 12 articles fitting the eligibility requirements. Five different indicators of poor oral health [number of teeth, periodontal disease, general oral health (dental caries prevalence and dental treatment needs), masticatory function, and occlusal force)] were found related to three outcomes linked to bone mineral density disorders (osteoporosis, fractures, and decreased bone mineral density), regardless of the adopted assessment tools. The number of teeth was negatively associated with fractures and a decreased bone mineral density, while periodontal disease was positively associated with osteoporosis and a decreased bone mineral density. Masticatory function was associated only with osteoporosis, while general oral health was associated only with fractures and occlusal force only with bone mineral density. The oral health indicator most frequently associated with outcomes linked to bone mineral density disorders was the number of teeth. The present findings could help to assess the contribution of each oral health indicator to the development of bone mineral density disorders in older age.

OBJECTIVE: Depression is prevalent among older adults. Although the number of missing teeth is considered to be associated with depression, the relationship between masticatory function, which is usually indicated by functional tooth units (FTUs), and depression in older adults remains unclear.
METHODS: This study used data from the National Health and Nutrition Examination Survey (NHANES) 2009-2018. The number of FTUs was defined as pairs of opposing natural and artificial teeth. Depression was accessed using the Patient Health Questionnaire (PHQ-9), and participants who scored ≥10 on PHQ-9 were diagnosed with depression. Logistic regression analyses, propensity score matching (PSM) analyses and subgroup analyses were conducted to assess the association between FTU and depression.
RESULTS: The analysis included 5764 individuals over 60 years. An association between FTU and the risk of depression among older adults was detected (odds ratio [OR] = 0.951, 95% confidence interval [CI] 0.915-0.989), suggesting protective roles of more FTUs. Significant increase in the risk of depression in 0 ≤ FTUs ≤ 3 was observed compared with 10 ≤ FTUs ≤ 12 (OR = 1.819, 95% CI 1.157-2.858). However, no significant increase in the risk of depression in 4 ≤ FTUs ≤ 9 was found. After PSM, significant increase in the risk of depression in 0 ≤ FTUs ≤ 3 was still detected compared with 4 ≤ FTUs ≤ 12 (OR = 1.484, 95% CI 1.030-2.136). Subgroup analyses demonstrated consistent results in all subgroups, except for individuals aged 76-80 and drinking regularly.
CONCLUSIONS: The findings suggested the association between impaired masticatory function and the risk of depression among older adults. Longitudinal studies are needed to elucidate the role of masticatory function impairment in the development of depression further.

OBJECTIVE: Japanese children have been shown to exhibit decreased masticatory function; however, limited evidence is available regarding the efficacy of certain food items in improving this issue. Therefore, this study examined the effects of chewing hard gummy candy on the masticatory function of Japanese children aged 6-12 years.
METHODS: The study included 26 participants (10 boys and 16 girls; mean age ± standard error = 9.3 ± 0.3 years) who were asked to chew hard gummy candy twice daily for 4 weeks at home. The lip-closing force, occlusal force, and masticatory performance of the participants were recorded before commencement (T1), 4 weeks after commencement (T2), and 4 weeks after completion (T3) of the training. Statistical analyses were performed using the Wilcoxon rank-sum test or the Wilcoxon signed-rank test with Bonferroni correction.
RESULTS: No correlation was observed between masticatory function and sex at T1. The lip-closing and right occlusal forces increased significantly after 4 weeks of exercise, and the effects persisted for another 4 weeks after completion. The masticatory performance also improved after training, although these effects did not persist and deteriorated substantially 4 weeks after completion of the training.
CONCLUSIONS: Habitual mastication training using hard gummy candy markedly enhances masticatory function (e.g., lip-closing force, occlusal force, and masticatory performance) in Japanese children.

The masticatory function of patients with skeletal anterior open bite (OPEN) is reported to be impaired compared with that of patients with normal occlusion (NORM). In this study, we compared brain blood flow (BBF) in patients with OPEN and NORM and investigated the factors related to BBF during mastication in patients with OPEN. The study included 17 individuals with NORM and 33 patients with OPEN. The following data were collected: number of occlusal contacts, jaw movement variables during mastication, and BBF measured with functional near-infrared spectroscopy during chewing. The number of occlusal contacts, maximum closing and opening speeds, closing angle, and vertical amplitude were smaller in the OPEN than in the NORM group. Interestingly, BBF increased less in the OPEN group. Correlation analysis revealed that several parameters, including number of occlusal contacts and closing angle, were correlated with changes in BBF during mastication. These results suggest that not only occlusion but also jaw movement variables and factors related to masticatory muscles contribute to the chewing-related increase in BBF. In conclusion, BBF increases less during mastication in patients with OPEN than in those with NORM. In addition, the higher increase in BBF is correlated with jaw movement. Together, we discovered that OPEN exhibits significant adverse effects not only on masticatory function but also on brain function.

BACKGROUND: Orofacial myofunctional disorders (OMD) are often associated with limitations of oral ingestion of solid food. The Test of Masticating and Swallowing Solids (ToMaSS) is a simple diagnostic tool to assess and quantify oropharyngeal efficiency while eating a standardised cracker.
OBJECTIVE: The objective of this study was to investigate the applicability and clinical utility of the ToMaSS in children with OMD.
METHODS: In this case-control study, data were collected from 18 children between 4 and 11 years with confirmed OMD. Inter-rater reliability and age effects on the ToMaSS parameters were investigated and the specific performance profile of the OMD children was identified.
RESULTS: Inter-rater reliability was excellent for the ToMaSS parameters \'bites\' (ICC = .999), \'masticatory cycles\' (ICC = .961), \'time\'(ICC≧ .999) and good for \'number of swallows\' (ICC = .810). \'Masticatory cycles\' and \'time\' decreased as a function of age with a significant difference in the \'number of masticatory cycles\' between the youngest (4-6 years) and oldest (10-14 years) participants (p = .006, Z = -2.739). Deviations from normative data in at least one of the four ToMaSS parameters were found in 90% of the OMD children with \'bites\', and \'masticatory cycles\' predominantly corresponding to the performances expected in typically-developing children in younger age groups.
CONCLUSIONS: The ToMaSS is a reliable diagnostic instrument and clinically useful to detect limited efficiency of oral solid bolus intake and specific impairments in chewing function and duration of food intake in children with OMD. Our data suggest that OMD is associated with delayed development of efficient solid bolus preparation.

Introduction Food questionnaire surveys are often used to evaluate masticatory function. In daily clinical practice in Japan, a survey is performed using a list of food groups suitable for the Japanese diet. The foods on the list were categorized into five food groups based on their mastication index. The patient\'s masticatory function is determined by the food groups that can be eaten. The masticatory index, which indicates chewability, was defined based on the percentage of 110 denture wearers who responded that they could eat food normally. A survey with this list is useful because of its simplicity; however, there is a lack of objective data on the physical properties of food samples. Consequently, to make the results of the food questionnaire survey more objective indicators, we performed a texture analysis of the food samples on the list. Methods We performed a texture analysis of 93 samples from 77 food items on the list. Compression tests were performed using a texture analyzer, and hardness, cohesiveness, adhesiveness, viscosity, and gumminess were calculated by a texture profile analysis. Results Even with the same ingredients, the results differed depending on the presence or absence of food skin, the direction of pressing (vertical or horizontal), cooking methods, and temperature differences. However, the masticatory index was negatively correlated with hardness (-0.4157, p<0.001) and gumminess which is determined as the product of hardness×cohesiveness (-0.4980, p<0.001). Conclusion This study suggests that the masticatory index indicating chewability may be related to the hardness and cohesiveness of food samples. Even for foods with the same hardness, the degree of difficulty in forming a food mass is expected to vary depending on differences in cohesiveness. Moreover, the presence or absence of food skin, the direction of food fibers, cooking methods, and temperature differences change the physical properties of the food. Therefore, the composition and structure of the foods or eating habits of patients should be taken into consideration when conducting a food questionnaire survey.

OBJECTIVE: Oral function in patients with schizophrenia has not been well-characterized. To address this, we performed a cross-sectional study of oral function in Japanese inpatients with schizophrenia.
METHODS: We measured oral function, including occlusal force, tongue-lip motor function, tongue pressure, and masticatory function in 130 Japanese inpatients with schizophrenia. We then compared the frequency of clinical signs of oral hypofunction among 63 non-elderly and 67 elderly inpatients with schizophrenia, as well as data from 98 elderly control participants from a previous Japanese study.
RESULTS: The frequency of reduced occlusal force was significantly higher in the elderly inpatients (76.2%) than in the non-elderly inpatients (43.9%) and elderly controls (43.9%). The frequency of decreased tongue-lip motor function in non-elderly inpatients (96.8%) and elderly inpatients (97.0%) was significantly higher than that in elderly controls (56.1%). The frequency of decreased tongue pressure in non-elderly inpatients (66.1%) and elderly inpatients (80.7%) was significantly higher than that in elderly controls (43.9%). Finally, the frequency of decreased masticatory function was highest in elderly inpatients (76.5%), followed by non-elderly inpatients (54.8%) and elderly controls (15.3%).
CONCLUSIONS: Oral function was decreased in both non-elderly and elderly Japanese inpatients with schizophrenia compared with elderly controls.