Objective Masticatory Function Research Articles

Factors associated with age-related changes in oral diadochokinesis and masticatory function in healthy old adults

BackgroundThis cross–sectional study aimed to identify factors associated with age-related changes in masticatory performance (MP) and oral diadochokinesis (ODK) and to provide normal values in healthy old adults for the diagnosis of oral frailty.MethodsA total of 385 participants were divided into three age groups (Gr1-3): 20–64 years, 65–74 years, and ≥ 75 years. To investigate tongue-lip motor function, ODK was assessed as the number of repetitions of the monosyllables /pa/ta/ka/. Four questionnaires were used to assess subjective masticatory ability, cognitive ability, and psychological status. MP, bite force, and occlusal area were tested to assess dynamic objective masticatory function, and the number of remaining teeth and functional tooth pairs were determined to assess static objective masticatory function. Handgrip strength (HG), oral dryness, and tongue pressure (TP) were assessed to identify influencing factors. Intergroup differences were evaluated by ANOVA and the Kruskal‒Wallis test, and correlations between ODK and orofacial factors were evaluated.ResultsThis study revealed significant age-related declines in TP, HG, and ODK, especially after 65 years of age. Factors affecting MP were posterior teeth, the Eichner index, bite force, occluding area, the Korean Mini-Mental State Examination (KMMSE) score, and ODK. Each ODK syllable was associated with different factors, but common factors associated with ODK were MP, HG, and PHQ-9 score. For the syllables /pa/ta/, the Eichner Index, TP, and oral dryness were also associated. For the syllable /ka/ in Gr3, MP, TP, HG, oral dryness, and the KMMSE score were associated.ConclusionsThese results could provide practical guidelines for oral rehabilitation in old adults and contribute to improving the understanding of age-related changes in oral function and the multidimensional nature of masticatory dynamics.

Orofacial function and temporomandibular disorders in Parkinson’s Disease: a case-controlled study

BackgroundThe difficulties and challenges faced by people with Parkinson’s disease (PD) in performing daily orofacial function are not systematically investigated. In this study, specific orofacial non-motor and motor symptoms and functions were systematically examined in PD patients in comparison to a matched control group.MethodsThe clinical case-controlled study was conducted from May 2021 to October 2022 and included persons with PD and age- and gender-matched persons without PD. The participants with PD were outpatients diagnosed with PD at the Department of Neurology at Bispebjerg University Hospital in Copenhagen, Denmark. The participants underwent a systematic clinical and relevant self-assessment of the orofacial function and temporomandibular disorders (TMD). The primary outcomes were objective and subjective assessments of the general orofacial function, mastication, swallowing, xerostomia and drooling. The secondary outcomes were the prevalence of TMD and orofacial pain. The difference in outcome measures between the two groups was analysed using chi-square and Mann–Whitney U test.ResultsThe study included 20 persons with PD and 20 age- and gender-matched persons without PD. Both objectively and subjectively, persons with PD had poorer orofacial function than the control group. Persons with PD had also a significantly more severe limitation of jaw mobility and jaw function. The objective masticatory function was also significantly reduced for persons with PD compared to the control group, and 60% of persons with PD found it difficult to eat foods with certain consistencies while 0% of the control group reported that problem. Persons with PD could swallow less water per second and the average swallowing event was significantly longer for PD persons. Even though PD persons reported more xerostomia (58% for persons with PD and 20% for control persons), they also reported significantly more drooling than the control group. Additionally, orofacial pain was more prevalent in PD persons.ConclusionsPersons with PD have a compromised orofacial function. Furthermore, the study indicates a link between PD and orofacial pain. In order to screen and treat persons with PD accordingly, healthcare professionals should be aware of and address these limitations and symptoms.Trial registrationThe trial was approved by the Regional Committee on Research Health Ethics of the Capital Region (H-20,047,464), the Danish Data Protection Agency (514 − 0510/20-3000), and registered at ClinicalTrials.gov (NCT05356845).

Assessment of subjective and objective masticatory function among elderly individuals with mild cognitive impairment

BackgroundMasticatory function is known to be related to cognitive ability; therefore, factors for improving masticatory function should be identified.AimsThis study aimed to identify factors influencing masticatory function associated with mild cognitive impairment (MCI) in elderly individuals.MethodsA total of 123 elderly participants [mean age: 76.5 ± 6.5 years; 82 females (66.7%), 41 males (33.3%)] were included. Cognitive function was evaluated by the Korean version of the Mini-Mental State Examination (KMMSE). Questionnaires for subjective evaluation were administered, and dynamic objective masticatory function evaluations, including chewing tests and bite force measurements, were performed. Intergroup differences were evaluated by the Wilcoxon rank-sum and chi-square test, and correlations between cognitive ability and masticatory function were evaluated by multilinear logistic regression.ResultsThe number of teeth, number of posterior teeth, bite force, masticatory ability index (MAI) and posterior support status showed significant differences between the normal (KMMSE > 23) and MCI (KMMSE ≤ 23) groups. However, only the MAI, representing dynamic masticatory performance, was significantly associated with MCI regardless of age, sex and removable prostheses. The number of teeth and posterior teeth, bite force, subjective masticatory ability and posterior occlusal support showed no significant association with MCI.DiscussionThese results suggested the importance of chewing function for preventing the progression of cognitive impairment.ConclusionsConsidering that only the MAI was significantly associated with MCI, it is more important to improve chewing efficiency by harmonizing therapeutic prosthetics with the surrounding masticatory system than simply increasing the number of teeth to prevent or delay cognitive impairment in elderly individuals.

Factors affecting subjective and objective masticatory function in older adults: Importance of an integrated approach

ObjectivesThis study aimed to subjectively and objectively assess masticatory function and identify related factors in older adults. MethodsFrom July 2017 to September 2018, we enrolled 115 healthy participants aged between 65 and 86 years. They underwent oral examination, and their stimulated salivary secretion rate and masseter muscle tone and biomechanical properties were assessed. Masticatory performance with two-colored chewing wax was objectively evaluated using the mixing ability index (MAI). Key food intake ability (KFIA) was subjectively assessed using a questionnaire. ResultsThe MAI score was significantly associated with the number of remaining teeth (r = 0.524, p < 0.001) and the tone (r = -0.222, p = 0.017), elasticity (r = -0.242, p = 0.009), and dynamic stiffness (r = -0.265, p = 0.004) of the masseter muscles. In contrast, the KFIA score was only significantly associated with the number of remaining teeth (r = 0.450, p < 0.001). A weak association between the MAI and KFIA scores was observed (r = 0.304, p = 0.001). ConclusionsA combination of objective and subjective methods should be used to accurately assess masticatory function in older adults. In addition to physical factors such as the number of remaining teeth, properties of the masticatory muscles should be evaluated to improve the masticatory function of older adults. Clinical significanceIn addition to dental problems, various maxillofacial and oral factors must be considered when establishing management strategies for the improvement of masticatory function in older adults.

Relationship between Masticatory Function and Bone Mineral Density in Community-Dwelling Elderly: A Cross-Sectional Study.

The relationship between masticatory function and bone mineral density (BMD) is unclear. This cross-sectional study examined this relationship after adjusting for confounding factors. The subjects were 702 community-dwelling elderly adults (306 men, 396 women) who had been recruited for the Community-Based Healthcare Research and Education study in 2019. Objective masticatory function was assessed using the gummy jelly method. The median for each descriptive statistic was 69.0 years for age, 86.2% for the young adult mean, and 18.0 for masticatory function. Comparisons of the groups with good and poor masticatory function by sex revealed a significant difference in muscle mass and the tooth number for both sexes (p < 0.05). Men showed significant differences in age (p < 0.05) and salivary occult blood findings (p < 0.05). Multivariate analysis using propensity scores showed a significant association between masticatory function and BMD in both sexes (men: odds ratio 163.0, 95% confidence interval 1.36–19,610.55, p = 0.04; women: odds ratio 48.65, 95% confidence interval 1.52–1561.15, p = 0.03 in women). Masticatory function and BMD in the community-dwelling elderly may be related. However, other factors, including frailty and sarcopenia, may also be involved. Regular oral health care by dentists and dental hygienists may benefit this population.

A new masticatory performance scale to integrate food biting, comminution and mixing ability in removable partial denture wearers.

The existing masticatory performance (MP) tests cannot comprehensively evaluate objective masticatory function. We aimed to examine the construct validity and responsiveness and determine the clinically minimum important difference (MID) and related factors of a newly developed MP scale to integrate food biting, comminution and mixing ability in patients with removable partial dentures (RPDs). Masticatory performance tests using gummy jelly, peanuts and colour-changeable gum were performed before and 3months after RPD treatment in 248 partially dentate patients. A 10-point ordinal subscale was created for each MP test based on the distributions of MP values, and the three subscales were integrated into a single scale (iMP scale). We analysed the correlations between MP values and iMP scores and determined the effect size for RPD treatments and the MID on the basis of patient perception of chewing ability. iMP scores exhibited moderate correlations with the three MP values (|ρ|=0.73-0.79, p<.001) and with the change scores (|ρ| =0.61-0.64, p<.001). The mean iMP score significantly increased after RPD treatment (p<.001), and the effect size was 0.35. Of the 248 patients, 55 (22%) reported a slight improvement in chewing ability with a mean iMP score change of 2.1 points. Sex and the number of missing teeth were significantly associated with iMP scores (p<.05). The iMP scale comprehensively evaluated objective masticatory function, including food biting, comminution and mixing ability in RPD wearers, and an increase of two points on the iMP scale was considered to be the MID in RPD treatments.

Can masticatory performance be predicted by using food acceptance questionnaire in elderly patients with removable dentures?

Although a food acceptance questionnaire is useful for subjective masticatory function assessments, its characteristics and limitations when applied to patients with removable dentures have been unclear. We therefore assessed the relationship between the subjective and objective masticatory function and explored whether or not a decreased masticatory function could be evaluated by food acceptance questionnaire. One hundred and nineteen patients >60years old with removable partial and/or complete dentures participated. Food acceptance score (FAS) was calculated by using Sato's questionnaire with 20 food items. Masticatory performance (MP) was assessed by a visual scoring method using a test gummy jelly (UHA Mikakuto). Simple/multiple regression analyses were performed to explain the objective masticatory function. The cut-off value of FAS was determined to predict a decreased masticatory function by sensitivity, specificity and receiver operating characteristics curve. No significant gender differences in MP or FAS were noted. Although both MP and FAS increased with the number of functional teeth, FAS was not significantly affected by age. The number of functional teeth, FAS and age had significant correlations with MP, with the number of functional teeth showing the strongest correlation. Multiple linear regression analyses identified the FAS as a significant explanatory variable for MP, and 70 was the optimal cut-off value for detecting a decreased masticatory function (MP score≤2) in the diagnosis of 'oral hypofunction'. Using FAS to assess the MP was deemed appropriate, and a score of 70 was the optimal cut-off value for detecting a decreased masticatory function.

Responsiveness of methods to evaluate objective masticatory function in removable partial denture treatments.

Purpose The aim of this study was to examine the responsiveness of chewing tests after removable partial denture (RPD) treatment in this prospective cohort study.Methods Pre- and post-RPD treatment, objective masticatory function was evaluated in 248 patients via chewing tests involving peanuts, a gummy jelly, and a color-changeable gum. A statistical comparison was performed between the pre- and post-treatment scores, and the standardized response mean (SRM) was determined as the treatment effect size (ES).Results After RPD treatment, the median particle size in the sieving method using peanuts significantly decreased, and the glucose concentration in the gummy jelly method significantly increased (P < 0.001). The ESs of the sieving and gummy jelly methods were larger (|SRM| = 0.3-0.4) than that of the gum method (|SRM| = 0.1). In the subgroup analysis, the sieving and gummy jelly methods resulted in a broader effective range (|SRM| ≥ 0.3) than the gum method. In patients without pre-treatment dentures, the ES was medium in the sieving method (|SRM| = 0.6) and weak in the gummy jelly and gum methods (|SRM| = 0.3-0.4). The pre-treatment level of masticatory function was significantly correlated with ES (ρ = 0.93, P < 0.001).Conclusions These results suggest that the sieving and gummy jelly methods are more responsive than the gum method for RPD treatment and that the pre-treatment scores affect the responsiveness.

Association between Masticatory Function and Sarcopenia in Elderly People: A Systematic Review and Meta-Analysis

Background: The purpose of this systematic review was to explore the association between masticatory function (subjective and objective assessment) and sarcopenia in elderly people. Methods: Multiple electronic databases including PubMed, Embase, Web of Science, and Cochrane Central Register of Controlled Trials were searched for all years up to October 1, 2019. Articles that evaluated occlusal force or chewing ability or difficulties in eating scores to explore the association between sarcopenia in elderly patients and healthy elderly peoples were included. A modified version of the Newcastle Ottawa Scale was used to assess study quality. The pooled standardized effect size with its corresponding 95% confidence interval for each parameter was calculated. Results: Of the 45 articles identified, three retrospective observational comparison studies, which had a lower risk of bias, were included: objective (occlusal force or chewing gum) and subjective (difficulties in eating scores) assessment were reported. Meta-analysis revealed that maximum occlusal force (standardized mean difference (SMD) = 0.36, confidence interval (CI) = 0.19-0.53, p ＜ 0.001)was significantly lower in subjects who were diagnosed with sarcopenia than in control groups. There were significant associations between sarcopenia and chewing ability using chewing gum (odds ratio (OR) = 2.34, CI = 1.09-5.02, p = 0.03) and difficulties in eating score (OR = 2.21, CI = 1.65-2.97, p ＜ 0.001). Conclusions: We found some limited evidence for an association between sarcopenia and masticatory function. Our meta-analysis supports an association between sarcopenia and subjective and objective masticatory function. More evidence is needed to demonstrate the association between masticatory function and sarcopenia in elderly people.

Factors related to dissociation between objective and subjective masticatory function in Japanese community-dwelling elderly adults.

Clinicians' evaluations of older adults sometimes reveal inconsistencies between objective and subjective dental status. This study investigated which factors contribute both to good objective masticatory function (OMF) and the poor subjective masticatory function (SMF) that often becomes a clinical issue. Study participants included 635 elderly community-dwelling Japanese adults who underwent a comprehensive geriatric health examination in 2012. SMF was assessed with a question from the Kihon Checklist on eating difficulties (poor or good). OMF was assessed by a colour-changing gum (poor or good). Also investigated were age, sex, depressive symptoms, instrumental activities of daily living (I-ADLs), number of people who joined the participant at dinner, grip strength, usual walking speed, number of remaining teeth, number of functional teeth and their occlusal force. The group with good OMF and good SMF, defined as group 1, and the group with good OMF but poor SMF, group 2, were compared. Logistic regression analyses confirmed that the number of remaining and functional teeth participants had was statistically unrelated to differences between OMF and SMF. Instead, differences were related to stronger depressive symptoms (OR=1.67, CI=1.14-2.44), less ability to conduct I-ADL activities (OR=0.73, CI=0.59-0.91), slower usual walking speeds (OR=0.18, CI=0.06-0.58) and less occlusal force (OR=0.99, CI=0.99-1.00). Depressive symptoms, I-ADLs, and physical function are shown to be significantly related to divergence between objective and subjective masticatory function in elderly Japanese. This suggests that dissociations between objective and subjective dental evaluations of elderly adults indicate need for assessment of their mental and physical function.

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

This study aimed to examine relevant factors for subjective and objective assessment of masticatory functions and elucidate any differences between the two methods. Previous studies have reported that the results of subjective and objective assessment of masticatory function in older people do not necessarily agree. This study included 487 community-dwelling Japanese older people (205 male and 282 female; mean age 74.1±6.3years) 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. 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. 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.

Relationships between perceived chewing ability, objective masticatory function and oral health-related quality of life in mandibulectomy or glossectomy patients with a dento-maxillary prosthesis

PurposeThis preliminary study examined whether the type of surgery performed for head and neck lesion was associated perceived chewing ability, objective masticatory function, and oral health-related quality of life (OHRQoL) in patients who required a dento-maxillary prosthesis postoperatively. MethodsThirty-eight patients with a dento-maxillary prosthesis were divided into three groups according to the type of surgery received: marginal mandibulectomy, segmental mandibulectomy with bony reconstruction, or glossectomy. Perceived chewing ability, objective mixing ability, and OHRQoL were evaluated using a food intake questionnaire, color-changeable chewing gum, and the Geriatric Oral Health Assessment Index (GOHAI), respectively. Differences in the scores obtained by the three measures were compared between the surgical groups using the Kruskal–Wallis test, and associations between the scores in each group were analyzed by Spearman's rank correlation analysis. ResultsObjective mixing ability was found to be significantly low only in patients who underwent glossectomy. No other measures differed significantly between the surgical groups. Perceived chewing ability and objective mixing ability were significantly associated in the marginal mandibulectomy and glossectomy groups but not in the segmental mandibulectomy group. Furthermore, GOHAI score was significantly associated with perceived chewing ability and objective mixing ability in the marginal mandibulectomy group. ConclusionsWithin the limitations of this study, the present findings suggest that the type of surgery received might influence food mixing ability. Associations among food mixing ability, perceived chewing and OHRQoL are not accountable depending on the type of surgery received, indicating the presence of other contributing factors to be considered.

A structural equation model to investigate the impact of missing occlusal units on objective masticatory function in patients with shortened dental arches

The aim of this study was to investigate the impact of missing occlusal units (MOUs) on objective masticatory function with respect to food comminuting and mixing ability. Sixty partially dentate patients (mean age, 64·1 years) with shortened dental arches participated in the study. Food comminuting ability was assessed using a masticatory performance test with peanuts as a test food. Food mixing ability was assessed using a mixing ability test with a two-coloured wax cube. Maximum bite force (MBF) was measured using a pressure-sensitive film as a mediator for food comminuting and mixing ability. A structural equation model was constructed based on a hypothesis that MOUs would be associated with reduced MBF and impairment of food comminuting and mixing ability. Structural equation modelling analysis found significant direct effects of MOU on median particle size and mixing ability index (MAI) (P < 0·001). In addition, MOU had significant indirect effects on median particle size and MAI with MBF as a mediator (P < 0·05). These results suggest that decrease in occlusal platform area and reduced MBF because of MOUs are associated with the impairment of food comminution and mixing in patients with shortened dental arches.

A structural equation model relating objective and subjective masticatory function and oral health‐related quality of life in patients with removable partial dentures

The aim of this study was to investigate the relationships between objective masticatory function with respect to masticatory performance and food mixing ability, patients' perception of chewing ability and oral health-related quality of life (OHRQoL). Partially dentate patients with removable partial dentures (n = 131, mean age 67·1 year) participated in the study. Four tests were performed to evaluate objective and subjective masticatory function and OHRQoL. Masticatory performance and food mixing ability were assessed using peanuts or a two-coloured wax cube as test items. Patients' perception of chewing ability was rated using a food intake questionnaire. OHRQoL was measured using the Japanese version of the oral health impact profile. A structural equation model was constructed based on hypothesis in which objective masticatory function would be related to OHRQoL via perceived chewing ability as a mediator. Structural equation modelling analysis found a statistically significant medium effect of perceived chewing ability on OHRQoL and statistically significant medium or small effects of masticatory performance on perceived chewing ability and OHRQoL (P < 0·05); however, the effect of food mixing ability on perceived chewing ability or OHRQoL was not statistically significant (P > 0·05). A fit index indicated that the model fitted well to the data (Goodness-of-fit index = 0·99). These results suggest that perceived chewing ability is a critical factor for OHRQoL and that masticatory performance rather than food mixing ability is important for perceived chewing ability and OHRQoL in patients with removable partial dentures.

Patients’ satisfaction and functional assessment of existing complete dentures: correlation with objective masticatory function

The aim of this study was to evaluate the correlation between patients' and dentist's assessment of dentures and to correlate these variables with objective measures of masticatory function. A sample of 28 edentulous individuals was selected, all wearing both complete dentures for at least 6 months and with no signs or symptoms of temporomandibular joint disorders. They rated their level of satisfaction with their dentures from 0 to 100 by means of a visual analogue scale, and dentures were scored by a dentist from 0 to 9 considering functional aspects. Tooth wear was evaluated on the posterior teeth of dentures considering the lack of occlusal anatomy. Masticatory performance and swallowing threshold tests were performed with an artificial test food (Optocal), and the median particle size was determined by the sieving method. The results showed that the mean satisfaction value of volunteers with their dentures was 49·1 and the median score of dentist's evaluation was 6. The Spearman correlation coefficient revealed no significant correlation between patients' and dentist's assessment of dentures (P>0·05). The median particle size for masticatory performance and swallowing thresholds was 5·5 ± 1·0 and 4·9 ± 1·2 mm, respectively. Data of both masticatory tests showed no significant correlation with patients' satisfaction or with dentist's evaluation of dentures. There was no difference of food comminution between subjects with and without excessive posterior tooth wear. It can be concluded that dentist's and patients' assessment of dentures were not correlated, and no correlation was observed between these variables and masticatory function.

Influence of occlusal vertical dimension on the masticatory performance during chewing with maxillary splints

Changing the occlusal vertical dimension is a common procedure in restorative dentistry, during treatment of patients with cranio-mandibular disorders, and during orthodontic and orthognathic treatment. The treatment may alter the length of the main jaw elevator muscles and the position of the mandibular head in the fossa temporalis. These changes may influence the bite forces that are generated during chewing and thus may affect the masticatory function. We measured the objective masticatory function, defined as masticatory performance, by determining an individual's capacity to pulverize a test food. The immediate influence of the increase in the occlusal vertical dimension on the masticatory performance was determined using three anatomical maxillary splints in a group of seven dentate subjects. The splints gave an increase in the occlusal vertical dimension of 2, 4 and 6 mm, respectively. Before we started the experiments the subjects practiced chewing with the splints during about 5 min. No significant differences were observed in masticatory performance among the conditions without and with the three splints. Thus, an increase in the occlusal vertical dimension up to 6 mm did not have a significant effect on the masticatory performance. Maxillary splints may be used to study the effect of occlusal factors on the chewing process by manipulating tooth shape and occlusal area of the splint.

Chewing performance before and after rehabilitation of post-canine teeth in man.

Missing teeth are often replaced by fixed or removable prosthodontic appliances to improve masticatory function. However, there have been few studies directly determining the influence of prosthodontic treatment on masticatory function. Our aim was to obtain information on the objective and subjective masticatory function of partially edentulous subjects before and after prosthetic restoration. In this way, the improvement of the masticatory function as a result of the treatment could be quantified. The objective and subjective masticatory function of a group of 15 subjects was determined before and after replacement of an average of 3.1 post-canine teeth. The results were compared with data from a control group of 26 subjects having a complete dentition. The total number of occluding post-canine teeth increased as a result of the prosthodontic treatment, yielding a significantly improved objective masticatory function. The average masticatory performance was found to approach the level of the control group if all occlusal units of the longest posterior side were replaced. Subjects with an incomplete dentition tended to chew predominantly on the side of the longest posterior arch. The average subjective masticatory function improved as a result of the treatment. The appreciation of the masticatory function after treatment was equal to that of the control group, despite an average of 2.7 missing teeth. However, no correlation was found between the additional number of occlusal units and the change in subjective masticatory performance. Rehabilitation of post-canine teeth restores some objective masticatory function and leads to an increased appreciation of the masticatory function, although no correlation was found between the changes in objective and subjective masticatory function.