Development of a simple method to measure masseter muscle mass.

OBJECTIVE: To develop a simple method to estimate masseter muscle mass. BACKGROUND: The masseter muscle is important for optimal oral function. A decrease in the masseter muscle mass may affect the oral and physical function of the whole body; therefore, it is an important entity to measure. However, to date, no easy measurement method has been developed for the same. Herein, we devised a simple method to estimate masseter muscle mass. In addition, we compared our method with magnetic resonance imaging (MRI) and skeletal muscle mass (SMM) to verify its validity. MATERIALS AND METHODS: We recorded the age, sex, masseter muscle mass (by MRI), number of retained natural teeth, number of functional teeth, length and thickness of masseter muscle, and skeletal muscle mass in 53 community-dwelling elderly people (21 men and 32 women, average age 72.9 ± 4.5 years). The estimated masseter muscle mass was calculated by multiplying the length, width and thickness of the muscle. RESULTS: The correlation coefficient between masseter muscle mass and estimated masseter muscle mass was r = .903; thus, a strong correlation was recognised. The correlation coefficient between the estimated masseter muscle mass and SMM was r = .279, considering age and sex. CONCLUSION: We obtained substantial results using our method for estimating the masseter muscle mass and verified its validity by comparing it with masseter muscle mass measured by MRI and SMM. We believe that our proposed technique is simple and useful for estimating masseter muscle mass.

Factors affecting masticatory function of community-dwelling older people: Investigation of the differences in the relevant factors for subjective and objective assessment.

OBJECTIVE: This study aimed to examine relevant factors for subjective and objective assessment of masticatory functions and elucidate any differences between the two methods. BACKGROUND: Previous studies have reported that the results of subjective and objective assessment of masticatory function in older people do not necessarily agree. MATERIALS AND METHODS: This study included 487 community-dwelling Japanese older people (205 male and 282 female; mean age 74.1±6.3 years) who participated in a comprehensive geriatric health examination. Basic information (gender and age), higher level of competence in daily living, depression, subjective masticatory function (SMF) and objective masticatory function (OMF) assessments, cognitive function, skeletal muscle mass, handgrip strength, gait speed and oral status (number of remaining and functional teeth, mouth dryness and occlusal force) were recorded. RESULTS: Multiple logistic regression analysis showed that depression (odds ratio [OR]: 1.181, 95% confidence interval [CI]: 1.094-1.275), mouth dryness (OR: 2.037, CI: 1.212-3.423) and occlusal force (OR: 0.997, CI: 0.996-0.999) were significantly associated with SMF, whereas higher level of competence in daily living (OR: 0.730 CI: 0.586-0.910), skeletal muscle mass (OR: 0.521 CI: 0.283-0.960), number of functional teeth (OR: 0.862 CI: 0.775-0.959), number of remaining teeth (OR: 0.868 CI: 0.810-0.930) and occlusal force (OR: 0.994, CI: 0.991-0.998) were associated with OMF. CONCLUSION: Subjective masticatory functionSMF and OMF were associated with different factors, suggesting that both mental and physical factors should be taken into consideration when treating decreased masticatory function.

Development of a multiple masticatory function model based on the evaluation of sarcopenia: A cross-sectional survey of the Otassha study.

OBJECTIVE: The masticatory function is intricately linked to several factors like natural teeth count, occlusion, masticatory muscles, and tongue coordination. This study's goal was to formulate a comprehensive masticatory function model, considering sarcopenia's conceptual structure, and subsequently validate its measurement efficacy. DESIGN: The study encompassed 753 participants (59.1 % women; mean age: 73.0 ± 5.1 years) from an urban community. The model amalgamated masseter muscle mass, occlusal force, and mixing ability. Based on the Asian Working Group for Sarcopenia 2019 classification, participants were categorized into a multiple masticatory dysfunction (MMD) or severe MMD (S-MMD) group. Logistic regression analysis gauged the model's validity, using serum albumin levels and self-reported chewing difficulties as dependent variables. RESULTS: Of the total, 61 (8.1 %) participants exhibited MMD, while 24 (3.2 %) had S-MMD. S-MMD was correlated with low serum albumin levels (odds ratio: 3.62; 95 % confidence interval: 1.07-12.29) and heightened self-reported chewing difficulties (odds ratio: 2.82; 95 % confidence interval: 1.09-7.28). CONCLUSIONS: Our multiple masticatory function model offers a straightforward approach for assessing MMD. Furthermore, the study establishes a link between S-MMD, nutritional vulnerability, and self-reported chewing challenges, thus affirming the model's credibility.

Risk factors for postoperative dysphagia in oral cancer.

With the founding of its Oral Cancer Center at the Ichikawa General Hospital, Tokyo Dental College established a support system for patients and family members that not only provides surgery and other conventional cancer-oriented treatments, but also palliative care, nutritional support, rehabilitation, and discharge support. With this in mind, the present study sought to examine the nature of support for oral cancer patients with postoperative eating and swallowing disorders by investigating these disorders and identifying their risk factors. The study population comprised 75 surviving oral cancer patients (46 men and 29 women) discharged from the Tokyo Dental College Oral Cancer Center following treatment over a 2-year period from April 2009 to March 2011. Risk factors affecting eating and swallowing function were identified by statistical analysis. Mean age of the patients was 67.3±13.7 years. Fifteen patients had stage I cancer, while 25 had stage II, 13 had stage III, and 22 had stage IV. The feeding route at the time of discharge was oral feeding in 74 patients and a combination of oral and gastrostomy tube feeding in 1 patient. The Tokyo Dental College Ichikawa General Hospital has standardized the expert evaluation and rehabilitation of oral cancer patients with eating and swallowing disorders by establishing a multidisciplinary support system from the preoperative stage onwards. In this context, the results of our analysis of factors influencing the ability of oral cancer patients to orally ingest food after treatment suggest that preoperative cancer stage classification, neck dissection, and tracheotomy are all influential factors. Patients affected by these factors require further multidisciplinary treatment, which in turn necessitates more extensive coordination with other medical professionals and community health care providers.

Oral function as an indexing parameter for mild cognitive impairment in older adults.

AIM: To investigate the association between mild cognitive impairment (MCI) and oral status, and to develop an oral-based screening index for MCI. METHODS: A cross-sectional study was carried out in a total of 5104 community-dwelling adults (aged ≥65 years) from the Obu Study of Health Promotion for the Elderly. Screening for MCI included a standardized personal interview, Mini-Mental State Examination, Geriatrics and Gerontology-Functional Assessment Tool (which included 8 tasks used to assess logical memory, word list memory, attention and executive function, processing speed, and visuospatial skill) and oral status. RESULTS: In our study, 930 individuals were diagnosed with MCI, whereas the remaining 2669 were not. Both men and women with MCI showed a significantly lower number of functional and present teeth, poorer oral diadochokinesis, and less palpation of masseter muscle tension (P < 0.01). Discriminant analysis of participants with MCI, between categories of pertinence and non-pertinence, showed significant associations for age, sex, educational background, handgrip strength, Geriatric Depression Scale score, Mini-Mental State Examination score, history of heart disease, albumin level and oral diadochokinesis representing oral motor skill. Although the diagnosis rate of our screening index for MCI was not high, it was in the acceptable range as a screening index. CONCLUSIONS: Oral motor skill, such as lip movement, might be impaired in patients with MCI. Detecting decreasing oral motor dexterity supports the early detection of MCI, and might be key to improve the prognosis of dementia. Geriatr Gerontol Int 2018; 18: 790-798.

Relationship Between Frailty and Oral Function in Community-Dwelling Elderly Adults.

OBJECTIVES: To determine the standard values of and age-related changes in objective oral function of healthy older people; compare oral function of robust, prefrail, and frail older people; and determine the association between oral function and frailty. DESIGN: Cross-sectional analysis. SETTING: General community. PARTICIPANTS: Elderly adults (≥65) from the Obu Study of Health Promotion for the Elderly were included and assigned to the robust, prefrail, and frail groups (N = 4,720). MEASUREMENTS: Each participant underwent detailed physical testing to assess frailty. The frailty phenotype was defined according to the presence of limitations in three or more of the following five domains: mobility, strength, endurance, physical activity, and nutrition. The numbers of present teeth and functional teeth were counted, and occlusal force, masseter muscle thickness, and oral diadochokinesis (ODK) rate were measured, along with sociodemographic and functional status, comorbidities, and blood chemistry. RESULTS: The number of present teeth, occlusal force, masseter muscle thickness, and ODK rate decreased with age. The frail group had significantly fewer present teeth (women aged ≥70), lower occlusal force (women aged ≥70; men aged ≥80), lower masseter muscle thickness, and lower ODK rate than the robust group. Multivariate analysis indicated that age, Geriatric Depression Scale score, skeletal muscle mass index, Mini-Mental State Examination score, hypertension, diabetes mellitus, albumin and triglyceride levels, and oral function were significantly associated with frailty. CONCLUSION: Age-related differences in oral function were found in older adults. Moreover, frail older individuals had significantly poorer oral function than prefrail and robust individuals. The risk of frailty was associated with lower occlusal force, masseter muscle thickness, and ODK rate.

Efficient drug delivery of Paclitaxel glycoside: a novel solubility gradient encapsulation into liposomes coupled with immunoliposomes preparation.

Although the encapsulation of paclitaxel into liposomes has been extensively studied, its significant hydrophobic and uncharged character has generated substantial difficulties concerning its efficient encapsulation into the inner water core of liposomes. We found that a more hydrophilic paclitaxel molecule, 7-glucosyloxyacetylpaclitaxel, retained tubulin polymerization stabilization activity. The hydrophilic nature of 7-glucosyloxyacetylpaclitaxel allowed its efficient encapsulation into the inner water core of liposomes, which was successfully accomplished using a remote loading method with a solubility gradient between 40% ethylene glycol and Cremophor EL/ethanol in PBS. Trastuzumab was then conjugated onto the surface of liposomes as immunoliposomes to selectively target human epidermal growth factor receptor-2 (HER2)-overexpressing cancer cells. In vitro cytotoxicity assays revealed that the immunoliposomes enhanced the toxicity of 7-glucosyloxyacetylpaclitaxel in HER2-overexpressing cancer cells and showed more rapid suppression of cell growth. The immunoliposomes strongly inhibited the tumor growth of HT-29 cells xenografted in nude mice. Notably, mice survived when treated with the immunoliposomes formulation, even when administered at a lethal dose of 7-glucosyloxyacetylpaclitaxel in vivo. This data successfully demonstrates immunoliposomes as a promising candidate for the efficient delivery of paclitaxel glycoside.