Maximum Occlusal Force Research Articles

Maximum Occlusal Force and Incident Functional Disability in Older Adults: The Tsurugaya Project.

The purpose of the current study was to investigate the association between maximum occlusal force, which is an objective predictor of masticatory performance, and incident functional disability in an elderly Japanese population. A prospective cohort study was conducted targeting 815 (51.7% female) community-dwelling older adults aged ≥70 y residing in the Tsurugaya district, Sendai, Japan. The outcome measurement was incident functional disability, defined as a first certification of long-term care insurance in Japan, which is determined on the basis of a strictly established, uniform, nationwide standard. During a median follow-up of 7.9 y (interquartile range, 4.8-7.9 y), information on long-term care insurance was obtained from the Sendai Municipal Authority. Bilateral maximum occlusal forces of the participants were measured using a horseshoe-shaped pressure-indicating film, and the participants were categorized into quartiles based on occlusal force. Adjusted hazard ratios for functional disability were estimated with Cox proportional hazard models, adjusted for age, sex, body mass index, medical history, smoking status, alcohol consumption, duration of education, depressive symptoms, cognitive impairment, physical functioning, marital status, history of falls, and number of remaining teeth. The multiple-adjusted hazard ratios and 95% confidence intervals (CIs) for incident functional disability compared to the greatest occlusal force quartile were 1.53 (95% CI, 1.02-2.33), 1.64 (95% CI, 1.06-2.55), and 1.64 (95% CI, 1.01-2.68) for the third, second, and first quartiles, respectively ( P for trend = 0.011). A lower maximum occlusal force was significantly associated with an increased risk of functional disability independently of possible confounders, including the number of remaining teeth. Occlusal force may be a useful indicator of the relationship between oral function and geriatric health. Knowledge Transfer Statement:This prospective cohort study demonstrated that lower maximum occlusal force was associated with an increased risk of functional disability in older adults, even after adjustment for possible confounding factors, including the number of remaining teeth. This strengthens the rationale regarding the association between oral function and geriatric health. Particularly in older adults, occlusal force is reduced by several factors other than tooth loss, such as the absence of a dental prostheses, sarcopenia in the masticatory muscle, poor periodontal condition, and orofacial pain. Our findings suggest that maximum occlusal force may be a useful biomarker associated with diverse parameters aside from the number of remaining teeth.

Occlusal force is correlated with cognitive function directly as well as indirectly via food intake in community-dwelling older Japanese: From the SONIC study.

BackgroundGrowing evidence suggests that oral health may be an important factor associated with cognitive function in aged populations. However, many previous studies on this topic used insensitive oral indicators or did not include certain essential covariates. Thus, we examined the association between occlusal force and cognitive function in a large sample of older adults, controlling for dietary intake, vascular risk factors, inflammatory biomarkers, depression, and genetic factors.MethodsIn this cross-sectional study of older community-dwelling Japanese adults, we examined data collected from 994 persons aged 70 years and 968 persons aged 80 years. Cognitive function was measured using the Japanese version of the Montreal Cognitive Assessment (MoCA-J). Oral status and function were evaluated according to the number of remaining teeth, periodontal pocket depth, and maximal occlusal force. Associations between MoCA-J scores and occlusal force were investigated via bivariate and multivariate analyses.ResultsEducation level, financial status, depression score, and intake of green and yellow vegetables, as well as number of teeth and occlusal force, were significantly correlated with MoCA-J scores in both age groups. Among individuals aged 80 years, CRP and periodontal status were weakly but significantly associated with MoCA-J score. After controlling for all significant variables via bivariate analyses, the correlation between maximal occlusal force and cognitive function persisted. A path analysis confirmed the hypothesis that cognitive function is associated with occlusal force directly as well as indirectly via food intake.ConclusionsAfter controlling for possible factors, maximal occlusal force was positively associated with cognitive function directly as well as indirectly through dietary intake.

Relationship between masticatory function and frailty in community-dwelling Japanese elderly.

Frailty likely results in impaired functioning, and frail individuals requiring long-term care have recently attracted the attention of researchers. In the oral health field, the number of elderly individuals who require intervention for retaining occlusion has been increasing, as has the number of remaining teeth and required prosthetic treatment. Additionally, the number of elderly with reduced masticatory function has also been increasing, and frailty is a suspected factor. The aim of this study is to clarify the relationship between frailty and masticatory function decline. A cross-sectional study. A total of 747 participants (total mean age 73.6 ± 5.8years old) underwent a comprehensive examination at the Tokyo Metropolitan Institute of Gerontology. Three masticatory functions were evaluated: maximum occlusal force, mixing ability, and self-reported chewing ability. Frailty was determined using all 25 questions of the Basic checklist developed by the Japanese Ministry of Health, Labour and Welfare, following the method reported by Satake et al. RESULTS: Binomial logistic analysis clarified the relationship between frailty and evaluation of each of the three masticatory functions. Significant correlations of pre-frailty or frailty with maximum occlusal force, mixing ability, and subjective chewing ability were observed. All three masticatory functions (maximum occlusal force, mixing ability, and self-reported chewing ability) were associated with pre-frailty or frailty in community-dwelling Japanese elderly.

Gonial Angle Measured by Orthopantomography as a Predictor of Maximum Occlusal Force

To establish the accuracy of measuring the gonial angle on an orthopantomogram (GAO), as defined by the anatomic relationship between the inferior and posterior borders of the mandible. Furthermore, to examine the relationship between GAO and maximum occlusal force (MOF) in the premolar and molar regions of healthy young adults. Orthopantomograms of dry mandibles were obtained in three orientations in the sagittal plane, to represent variation in image acquisition in clinical settings. The GAO was measured using image-processing software, and reliability was analyzed using the intraclass correlation coefficient. Then, GAO, MOF, gender, and body mass index (BMI) were measured in a cohort of healthy young adult volunteers. MOF was measured using an Occlusal Force Meter GM 10 device. The relationships between GAO, MOF, sex, and BMI were examined using the Pearson correlation coefficient and multiple regression analysis. In five dry mandibles, there was a high correlation between the GAOs measured in the different orientations (p < 0.001). In 58 healthy volunteers (31 women and 27 men, mean age 24.6 years), the mean GAO was 123.3° ± 7.5°. The mean MOFs at the first premolar, second premolar, and first molar teeth were 256.4 N ± 128.3 N, 319.0N ± 171.7 N, and 487.5 N ± 227.2 N, respectively. Men had significantly greater MOF than women at all teeth. The GAO was significantly inversely correlated with MOF at the second premolar (r = -0.376, p = 0.005) and first molar teeth (r = -0.479, p < 0.001). Multiple regression analysis showed that GAO was a significant explanatory factor for MOF at the second premolar and first molar teeth (p = 0.012 and 0.001, respectively). GAOs were measured accurately on the orthopantomograms taken in this study and were a reliable predictor of MOF between the second premolar and first molar teeth. A smaller GAO was associated with a greater MOF at the second premolar and first molar teeth.

Outcomes Assessment of Treating Completely Edentulous Patients with a Fixed Implant-Supported Profile Prosthesis Utilizing a Graftless Approach. Part 2: Patient-Related Outcomes.

To assess outcomes of treating completely edentulous patients with a fixed implant-supported profile prosthesis, utilizing a graftless approach, for the maxilla and for the mandible, with an emphasis on patient-related outcomes, specifically maximum occlusal force, patient satisfaction, and impact on quality of life. This was a cross-sectional study with the following inclusion criteria: completely edentulous patients rehabilitated with a fixed implant-supported profile denture, utilizing a graftless approach. Patients fulfilling the inclusion criteria were asked to participate in the study during their follow-up visits; hence, a consecutive sampling strategy was used. To measure maximum occlusal force, a digital occlusal force gauge was used. Subjects were asked to answer a paper survey distributed in the clinic. The survey contained general demographic questions, visual analog scale (VAS) categories, and Oral Health Impact Profile-14 (OHIP-14). The mean VAS score was 8.9 out of a possible 10. The mean OHIP-14 score was 7.5 out of a possible 56. The mean maximum occlusal force recorded in the anterior region was 108 Ncm. The mean maximum occlusal force recorded in the posterior region was 205 Ncm. Results indicated that patients treated with a graftless approach reported high satisfaction and impact on quality of life. Regarding maximum occlusal force values, significant differences between men and women were reported. The impact on quality of life seemed to improve when patients presented completely edentulous at the time of treatment as opposed to terminal dentition. Finally, significant positive correlations were detected between satisfaction and impact on quality of life, impact on quality of life and posterior maximum occlusal force, anterior and posterior maximum occlusal force, and complications and anterior maximum occlusal force.

Does Neuroticism Influence Oral Health-Related QOL in Patients with Removable Partial Dentures?

This prospective cohort study investigated the relationship between patient neuroticism and oral health-related quality of life (OHRQoL) before and after prosthetic treatment as well as changes in OHRQoL-namely, treatment efficacy. Sixty-three patients (23 men and 40 women; mean age 67.2 ± 8.6 years), who were scheduled to receive new removable partial dentures (RPDs), were recruited. OHRQoL was assessed using the Japanese version of the Oral Health Impact Profile (OHIP-J). The Japanese version of the NEO Five-Factor Inventory (NEO-FFI) was used to assess neuroticism. Spearman's rank correlation coefficient was calculated to determine the association between neuroticism and OHIP-J scores before and after treatment. After stratifying patients according to neuroticism score, the Wilcoxon signed-rank test was used for intragroup comparison of OHIP-J scores before and after treatment. Moreover, logistic regression analysis was used to determine the impact of covariates on treatment efficacy such as age, sex, Eichner classification, neuroticism, changes in maximal occlusal force, and OHIP-J scores before treatment. Statistical analyses showed that higher neuroticism scores were associated with higher total OHIP-J scores before treatment ( r = 0.41, P = 0.001) but were not associated with OHIP-J scores after treatment ( r = 0.07, P = 0.566). When the effect of all independent variables was analyzed in multivariate analysis, neuroticism and OHIP-J scores before treatment affected treatment efficacy. These results suggest that OHRQoL of patients with higher levels of neuroticism was low before prosthetic treatment but significantly improved by oral rehabilitation with RPDs to the same level as patients with lower levels of neuroticism. Knowledge Transfer Statement: The results of this study may change the clinical perception of the effect of prosthetic rehabilitation with removable partial dentures in patients with higher levels of neuroticism. The study concluded that prosthetic rehabilitation could contribute toward satisfaction even in neurotic patients, who are presumed to show less satisfaction with their oral status.

Identification of dietary patterns and their relationships with general and oral health in the very old.

Little is known about the dietary patterns of Asian populations aged >=85 years and their associated factors. Thus, we aimed to (1) identify these dietary patterns and (2) clarify the relationships between the dietary pattern and health outcomes in a community-dwelling very old population. The Tokyo Oldest Old Survey on Total Health study is an observational cohort study comprising 512 Japanese subjects (women, n=288; men, n=224; age, 87.8±2.2 years). Dietary patterns were assessed by principal component analysis using a brief self-administered diet history questionnaire. Barthel index, Mini-Mental State Examination, and oral health status [maximum occlusal force (MOF), denture use, and dentulous / edentulous state] were also measured. Two dietary patterns were identified. The first factor component "traditional Japanese" was characterized by a high consumption of vegetables, seaweed, legumes, and fish. The second factor component "noodles and confectioneries" was characterized by a high consumption of noodles, confectioneries, and non-alcoholic beverages. Multivariable analysis showed that the "traditional Japanese" dietary pattern was inversely associated with dentulous state (OR: 0.53; 95% CI: 0.34-0.82), the lowest tertile of MOF (OR: 0.64; 95% CI: 0.42-0.99), and denture use (OR: 2.42; 95% CI: 1.26- 4.63) even after adjustment for potential confounders. Furthermore, the "noodles and confectioneries" dietary pattern was inversely associated with the lowest tertile of MOF (OR: 0.62; 95% CI: 0.40-0.94). However, there were no significant associations between these dietary patterns and disability or cognitive function. We identified two dietary patterns in the very old population, which were associated with oral health status.

Efficacy of botulinum toxin in treating myofascial pain and occlusal force characteristics of masticatory muscles in bruxism.

The present study was conducted in patients with bruxism to evaluate the effect of botulinum toxin type A (BTX-A) (Botox, Allergan, Inc., Irvine, CA, USA) in the treatment of myofascial pain and the occlusal force characteristics of masticatory muscles. Twenty-four diagnosed with bruxism were randomly divided into three groups (n = 8) and treated by bilateral intramuscular injection of BTX-A and placebo-treated with saline placebo injections and control group where no injections were given. The clinical parameters such as pain at rest and during chewing were assessed and occlusal force analysis system to measure the distribution of occlusal force in bruxism patients. All the three groups were assessed at baseline time and at 1 week, 3 months, and 6 months follow-up appointments. Descriptive analysis showed that improvements in parameters such as pain at rest; pain during chewing clinical outcome variables were higher in the botox treated group than in the placebo-treated subjects. The pain at rest and at chewing decreased in the BTX-A group while remaining constant in the placebo group and control group. There was a significant change in maximum occlusal force in the BTX-A group compared with the other two groups (P < 0.05, post hoc Bonferroni test, no exact P value), and there was no significant difference between the placebo and control groups (post hoc Bonferroni test, no exact P value). Results from the present study supported the efficacy of BTX-A to reduce myofascial pain symptoms in bruxers, and effective in reducing the occlusal force.

Validity of using multi-frequency bioelectrical impedance analysis to measure skeletal muscle mass in preschool children.

[Purposes] Although it is recommended to develop a habit of physical activities, there is no easy way to measure skeletal muscle mass in preschool children, which cause the difficulty of evaluation. The purpose of this study was to examine the validity of body composition including the skeletal muscle mass assessment using multi-frequency bioelectrical impedance analysis by comparing body fat mass obtained by using multi-frequency bioelectrical impedance analysis method and body mass index formulas. [Subjects and Methods] Ninety-four children were surveyed for age, height, weight, grip strength, maximum occlusal force, thickness of muscle and fat mass (masseter and lower limb), body fat mass, skeletal muscle mass, and calf circumference. We assessed additional parameters, which were thought to be related to skeletal muscle mass, to ensure validity. [Results] A strong correlation was found in body fat mass values obtained using the multi-frequency bioelectrical impedance analysis method and those obtained using the body mass index formulas. Additionally, strong correlation coefficients were found between the skeletal muscle mass/height obtained using the multi-frequency bioelectrical impedance analysis method and grip strength and calf circumference. [Conclusion] Our results indicate that skeletal muscle mass can be reliably measured using the multi-frequency bioelectrical impedance analysis method in preschool children.

Evaluation of the relationship between the occlusion parameters and symptoms of the temporomandibular joint disorder.

Background.The aetiology of temporomandibular joint disorders (TMD) is multifactorial, whereas occlusal disharmony is one of the predisposing factors. Researchers still discuss the relation between occlusion and TMD.Objective.The study aims to investigate the relation between static occlusal parameters and TMD clinical symptoms using T-Scan II analysis system.Material and methods.The sample consisted of 44 persons divided into the treatment group of 20 TMD patients and the control group of 24 subjects without TMD. The main task of T-Scan II computerized occlusal analysis system was to record every patient’s occlusion and estimate static occlusal parameters: centre of occlusal force, asymmetry index of maximum occlusal force and occlusion time. These results were compared between groups, data related to patients’ complaints and clinical symptoms. The analysis was carried out using Mann-Whitney U, Kruskal-Wallis and Chi-square tests.Results.Averages of the centre of occlusal force in TMD subjects were 6.55 ± 0.99 mm, in the control group – 5.88 ± 0.69 mm; the asymmetry index of maximum occlusal force averages: 15.90 ± 2.71 and 12.93 ± 1.88; occlusion time: 0.281 ± 0.036 s and 0.236 ± 0.022 s, respectively. There were no statistically significant differences between two groups but they were found in the centre of occlusal force and the asymmetry index in the two groups (p < 0.05).Conclusions.There exists a relation between complaints of patients with TMD and static occlusion parameters. Values of the centre of the occlusal force distance and the asymmetry index of occlusal force in TMD patients with pain in the temporomandibular joint (TMJ) were significantly higher than in the control group.

In patients with shortened dental arches do removable dental prostheses improve masticatory performance?

Data sourcesPubMed, Medline, Cochrane Library, Embase and Science Direct.Study selectionStudies published in English providing data on patients with shortened dental arch (SDA) and extreme SDA (ESDA) and masticatory performance with removable dental prostheses (RDP) were included.Data extraction and synthesisTwo reviewers independently selected studies and abstracted data, with disagreements being resolved by discussion.ResultsEight studies were included; four reported on comminution studies, three on mixing ability and one included both. In patients with ESDA comminution or mixing ability was 28-39% lower compared to patients with a complete dentition. In two studies, comminution outcomes when chewing with an RDP ranged from 2% to 32% reduction, indicating better chewing function (smaller X50) compared to comminution without the RDP. One study reported 28-83% lower mixing ability when chewing at the RDP side than chewing at the dentulous side. Generally, more artificial teeth (or longer occlusal platform) in experimental RDPs resulted in better comminution and better mixing ability (significant in four out of five studies), indicating a 'dose-effect' relationship. Two of the eight studies reported on biting force with higher maximum occlusal force for biting with natural teeth than for biting with artificial teeth in a distal-extension RDP.ConclusionsWithin the limitations of this review it can be concluded that subjects with (E)SDA had a reduced masticatory performance in the order of 30-40%. Distal-extension RDPs compensated for this reduction only partially, namely in the order of 50%. RDP effects on chewing frequency were not conclusive.

Dietary Intake Is Associated with Occlusal Force Rather Than Number of Teeth in 80-y-Old Japanese.

There has been a growing interest in the association between the number of teeth and dietary intake in older populations. However, people around the age of 80 y have frequently lost most of their teeth, and dental prostheses replacing the missing teeth play an important role in masticatory function. Therefore, masticatory function cannot be evaluated by the number of teeth alone. The occlusal force of the complete dental arches is an index of masticatory function, reflecting not only the number of teeth, but the effect of removable dentures. The purpose of this cross-sectional study was to determine the relative importance of the number of teeth and occlusal force in association with dietary intake in 80-y-old Japanese people. This study included 760 community-dwelling Japanese people aged 79 y to 81 y. The authors measured bilateral maximal occlusal force in the intercuspal position using pressure-sensitive sheets. Removable denture wearers kept their dentures in place during the measurements. Energy-adjusted food groups and nutrient intake during the preceding month were assessed by a brief self-administered diet history questionnaire. The authors assessed linear trends in food and nutrient intake in relation to the number of teeth and occlusal force after adjusting for gender and socioeconomic status (education level, financial status, family structure, resident area and BMI). P values of < 0.05 were considered to be statistically significant. The authors found that the number of teeth was not associated with the energy-adjusted intake of any food group examined. In contrast, a decline in occlusal force was significantly associated with a lower intake of vegetables, fish and shellfish, protein, polyunsaturated fatty acids, dietary fiber and most vitamins and minerals ( P for trend < 0.05). We conclude that food and nutrient intake was more closely associated with occlusal force than the number of teeth in community-dwelling Japanese people aged 79 y to 81 y. Knowledge Transfer Statement: This cross-sectional study of older Japanese people showed that, after controlling for considerable covariates, occlusal force rather than the number of teeth is positively associated with energy-adjusted intake of vegetables, fish and shellfish, protein, polyunsaturated fatty acids, dietary fiber and most of vitamins and minerals. This means that reduced occlusal force may unconsciously lead older people toward a habitual unhealthy dietary intake. Older people have frequently lost most of their teeth and require prosthetics to restore masticatory function. Bilateral occlusal force is therefore a better measure of masticatory function than the number of remaining teeth. Our findings suggest that prosthetic rehabilitation is a significant factor in the prevention and management of chronic diseases and frailty through better dietary intake in older populations.

Association between maximum occlusal force and 3-year all-cause mortality in community-dwelling elderly people.

BackgroundAmong the very elderly, poor oral health reduces life expectancy. In this study, differences in the magnitude of the maximum occlusal force (MOF) in the very elderly were examined in terms of effects on all-cause mortality in a 3-year follow-up.MethodsWe evaluated 489 community-living elderly individuals aged 85 years or older. MOF was measured using an occlusal force measuring device, and participants were classified into three groups according to gender- and dental status-sensitive tertiles. Demographic variables, cognitive, physical function, psychological status, oral health, comorbidity, and blood chemistry factors were assessed. One-way analyses of variance, χ2 tests, and the Kruskal-Wallis test were used for statistical analyses. The relationship between MOF tertiles and 3-year all-cause mortality was examined using a multivariate Cox model analysis after adjusting for confounding factors.ResultsMOF tertiles were significantly associated with cognitive impairment, number of teeth, limitations on chewable foods, handgrip strength, timed up-and-go test, and diabetes mellitus. During the follow-up period, 74 subjects died. Subjects with the highest MOF had a significantly lower mortality rate than other groups (log rank P = 0.031). In the univariate Cox model, MOF tertiles were independently associated with a lower risk of death (HR = 0.69, 95 % CI = 0.51–0.91). Even after adjusting for various confounders in the multivariate Cox model (Model 1), MOF was independently associated with a lower risk of death (HR = 0.67, 95 % CI = 0.50–0.91). In model 2, we added handgrip strength as a confounder and found that the HR for MOF was attenuated (HR = 0.73, 95 % CI = 0.54–0.99), but still statistically significant.ConclusionsIn a cohort of the very elderly, MOF was independently associated with all-cause mortality after adjusting for various health issues. Moreover, this independent association remained after a further adjustment for handgrip strength; however, the HR was attenuated. This suggests that MOF and handgrip strength may share a common mechanism of a general decrease in muscle strength, possibly sarcopenia, which is a significant cause of mortality in the very old.

Occlusal force characteristics of masseteric muscles after intramuscular injection of botulinum toxin A(BTX – A)for treatment of temporomandibular disorder

Our aim was to evaluate the occlusal force and therapeutic efficacy of the masseteric muscles after intramuscular injection of botulinum toxin A (BTX-A) for the treatment of patients with concurrent temporomandibular disorders (TMD) and bruxism. Thirty patients with TMD associated with bruxism were randomised into three groups (n=10 in each group), and treated by bilateral intramuscular injection of BTX-A into the masseter, placebo, or control. We used an occlusal force analysis system to collect several measures of occlusal force such as duration of biting and closing, the maximum occlusal force, and the distribution of occlusal force. The occlusal force in the intercuspid position was reduced in all three groups. There was a significant difference between the BTX-A and placebo groups (F(df=1)=8.08, p=0.01) but not between the control group and the other two(F(df=1)=4.34, p=0.047). The duration of occlusion was significantly increased in the BTX-A group after 3 months’ treatment (t=4.07, p=0.003). The asymmetrical distribution of occlusal force was reduced in all three groups, but not significantly so (Levene's test F(df=2)=0.25, p=0.78,ANOVA F(df=2)=0.50, p=0.61). Treatment of TMD with BTX-A is effective in reducing the occlusal force, but psychological intervention plays an important part in treatment.

Taste detection ability of elderly nursing home residents.

Due to the rapid rise of aged populations throughout the world, it is essential to elucidate the cause of taste dysfunction, because it may reduce appetite, leading to inadequate dietary intake. We aimed to compare taste detection ability between dependently and independently living geriatric individuals of nearly the same age with oral status. Forty-three elderly individuals considered to be cognitively eligible and residing in nursing homes in Japan were enrolled (n = 43, 82·3 ± 8·5 years) and were compared with an independently living elderly group (n = 949, 79·9 ± 0·8 years), aiming to compare taste detection ability between dependently and independently living elders of nearly the same age. Information regarding comorbidity and medication was obtained as general health status, and oral status including number of present teeth, denture usage and maximal occlusal force was also noted. In the dependently living group, 69·4%, 14·3%, 16·3% and 8·2% of participants could detect sweet, sour, salty and bitter tastes, respectively, which was significantly lower than the independently living group for each taste (97·9%, 70·8%, 89·6% and 43·8% for sweet, sour, salty and bitter tastes, respectively). The multivariate logistic regression analysis revealed that residing in nursing homes was associated with reduced sensitivity for four different tastes. The diseases and the situation of dependent elders were more likely the cause of the decreased taste sensitivity.

Association of Occlusal Force with Cognition in Independent Older Japanese People.

Recent longitudinal studies have shown the influence of multiple tooth loss on cognitive impairment, and earlier studies suggested that periodontal disease was related to cognitive decline. Tooth loss is associated with reduced masticatory function, which may affect stimulation of the central nervous system and dietary intake. Although some studies have reported a relationship between chewing ability and cognitive function, no studies have examined this area in terms of objective oral function. The aim of this study was to examine the association of occlusal force with cognitive decline in the preclinical stage among older people with higher-level functional capacity. This cross-sectional study for community-dwelling older people living in urban and rural areas in Japan examined 994 persons in the 70-y group (age range, 69-71 y) and 968 persons in the 80-y group (age range, 79-81 y). Retention of higher-level competence was defined according to the Tokyo Metropolitan Institute of Gerontology Index of Competence. Cognitive function was measured with the Japanese version of the Montreal Cognitive Assessment (MoCA-J). Oral status and function were assessed by the number of remaining teeth, periodontal pocket depth, and maximal occlusal force. Associations between the MoCA-J score and occlusal force were examined by bivariate and multivariate analysis. Approximately one-half of the participants retained higher-level functional capacity and were included in the analysis. Multiple regression analysis showed that occlusal force was significantly related to cognitive function after controlling for possible predictors including age, sex, socioeconomic status, medical condition, and handgrip strength. The number of remaining teeth and periodontal pocket depth were not significantly associated with cognitive function. Among community-dwelling older people with retained competence, maximal occlusal force was positively associated with their cognitive function. These results suggest that oral function might be a predictor for preclinical cognitive decline. Knowledge Transfer Statement: Multiple regression analysis showed that occlusal force was significantly related to cognition after controlling for possible predictors including handgrip strength as an indicator of general muscle strength, suggesting the independence of oral function. The number of remaining teeth did not have this association. The majority of older people have lost teeth and have received prosthodontic treatment, and their occlusal force is determined not only by the number of remaining teeth but also by prosthetic rehabilitation. These results can be used by clinicians focusing on prevention of tooth loss among the entire population, as well as to encourage partially edentulous and fully edentulous patients to restore their oral function with prostheses in order to eliminate a possible risk factor for cognitive impairment.

Occlusal force and its distribution in the position of maximum intercuspation in individual normal occlusion: a cross-sectional study

To investigate the occlusal force in the position of maximum intercuspation in the population with individual normal occlusion using a new occlusal analyzing equipment (TeeTester). Twenty-nine volunteers aged from 21 to 32 years were recruited. Occlusal analysis was performed using TeeTester. An arch model of each subject was retrieved in order to measure the tooth width and to calculate the force applied on each tooth. The occlusal force in the position of maximum intercuspation was (900 ± 361) N (range: 335-1 727 N). The maximum occlusal force was correlated with the contacting area. The mean value of occlusal force on the molars ranged from 107 to 156 N, with the mean value on the first molar greater than that on the second molar within the same quadrant. The mean value of occlusal force ranged from 39 to 66 N on the premolars, and from 11 to 33 N on the front teeth. There is a great variation of occlusal force in maximum intercuspation in individual normal occlusion. TeeTester occlusal analyzing system provides absolute occlusal force in kilogram and can be cowerted to N, which may assist clinical examination in patients.

Assessment of swallowing and masticatory performance in obturator wearers: a clinical study.

PURPOSETo assess function by identifying changes in swallowing and masticatory performance in maxillary obturator prosthesis wearers.MATERIALS AND METHODSSixty subjects were recruited for the study, of which 20 were obturator wearers, 20 were completely dentulous and 20 had removable partial/complete dentures with similar Eichner's Index. Swallowing ability was evaluated with and without obturator using the "Water Drinking Test"; Masticatory performance was evaluated with the Sieve test; and maximum occlusal force was recorded with the help of a digital bite sensor. The data was analyzed using the Statistical Package for Social Science version 15.0 with a confidence level at 95%.RESULTSProfile, behavior of drinking and time taken to drink were significantly improved (P<.001) in subjects after wearing obturator. Masticatory performance was not significantly different (P=.252) in obturator wearer when compared with dentulous or removable partial/complete denture wearer, but significantly (P<.001) high inter group difference in maximum occlusal force existed. Correlation between masticatory performance and maximum occlusal force was not significant (P=.124).CONCLUSIONSwallowing ability was significantly improved after wearing obturator but masticatory performance was not significantly different from those having similar occlusal support zone in their dentition.

Using the T-scan III system to analyze occlusal function in mandibular reconstruction patients: a pilot study.

This study was designed to analyze the post-rehabilitation occlusal function of subjects treated with complex mandibular resection and subsequently rehabilitated with fibula osteoseptocutaneous flaps, dental implants, and fixed prostheses utilizing the T-scan system. Ten mandibular complex resection cases that adopted fibula osteoseptocutaneous flaps, dental implants, and fixed prostheses to reconstruct occlusal function were analyzed. The mandibular reconstructions were divided into three groups based on size: full mandibular reconstructions, mandibular reconstructions larger than half of the arch, and mandibular reconstructions smaller than half of the arch. The T-scan III system was used to measure maximum occlusal force, occlusal time, anterior-posterior as well as left-right occlusal force asymmetries, and anterior-posterior as well as left-right asymmetrical locations of occlusal centers. Subjects with larger mandibular reconstructions and dental implants with fixed partial dentures demonstrated decreased average occlusal force; however, the difference did not reach the statistically significant level (p > 0.05). The most significant asymmetry of occlusal center location occurred among subjects with mandibular reconstructed areas larger than half of the mandibular arch. Comparison of the parameters of T-scan system used to analyze the occlusal function showed that the occlusal force was not an objective reference. Measurements of the location of the occlusal center appeared more repeatable, and were less affected by additional factors. The research results of this study showed that the size of a reconstruction did not affect the occlusal force after reconstruction and larger reconstructed areas did not decrease the average occlusal force. The most significant parameter was left and right asymmetry of the occlusion center (LROC) and was measured in subjects with reconstruction areas larger than half of the arch.

Association of personality traits with oral health-related quality of life independently of objective oral health status: A study of community-dwelling elderly Japanese

ObjectivesOral health-related quality of life (OHRQoL) is being increasingly used in epidemiologic studies of dentistry. However, patient-reported OHRQoL does not always coincide with clinical measures. Previous studies have shown a relationship between OHRQoL and personality, but did not concomitantly investigate oral function. We aimed to examine the association among personality traits, oral function, and OHRQoL using a large sample of community-dwelling Japanese elderly. MethodsThe participants (n=938; age, 69–71 years) were drawn from a complete enumeration of an urban area and a rural area of both the Tokyo metropolitan area and Hyogo Prefecture. The self-perceived impact of OHRQoL was measured using the Geriatric Oral Health Assessment Index (GOHAI). The oral status and socioeconomic characteristics were recorded in each participant, and personality traits (neuroticism, extraversion, openness to experience, agreeableness, and conscientiousness) were assessed with the NEO-five-factor inventory. Multiple linear regression analysis was performed to examine the relationships between OHRQoL and other factors, with p<0.05 considered to be statistically significant. ResultsNeuroticism was negatively associated with the GOHAI score in bivariate analyses (Spearman rank-order correlation coefficient (rs)=−0.20), whereas extraversion was positively associated (rs=0.17). In the regression analyses, neuroticism (standardized partial regression coefficient (β)=−0.179) and extraversion (β=0.094) were significantly associated with the GOHAI scores independently of the number of teeth, maximal occlusal force, and financial status. ConclusionsPersonality traits are associated with OHRQoL independently of objective measures of oral health status in community-dwelling elderly Japanese. Clinical significanceThis study showed personality traits are associated with OHRQoL independently of dental status and oral function in old Japanese people. As elderly patients undergo increasingly complex dental treatments, there is a need to evaluate patient personality traits prior to dental treatment and predict patient expectations and responses to planned treatment. This is advantageous in determining the most appropriate therapy.