Association of bite force with ageing and occlusal support in older adults

OBJECTIVES: The purpose of this study was to investigate the effect of ageing, occlusal support and TMJ condition and general health status on bite force in older adults. METHODS: The study sample consisted of 850 independently-living people over the age of 60 years. Bilateral maximal bite force in the intercuspal position was measured with pressure sensitive sheets. TMJ noise by palpation and limitation of mouth opening (less than 40 mm) were assessed. Subjects were grouped into three categories by occlusal support according to the Eichner Index. RESULTS: A multiple logistic regression analysis showed that whether participants had low bite force or not was significantly associated with gender, age, self-rated general health and occlusal support, but not TMJ noise or mouth opening limitation. Overall bite force showed a statistically significant but weak negative Spearman's correlation with age (r=-0.24, p<0.001). However, there was no significant correlation between age and bite force in the Eichner C group for males or in any of the Eichner classification for females. CONCLUSIONS: Decline of occlusal support and general health might translate into reduction of bite force with ageing in older adults. Since tooth loss is not physiological ageing but pathological ageing, it cannot be shown that reduction of bite force is a natural effect of ageing.     

Association of masticatory performance with age, posterior occlusal contacts, occlusal force, and salivary flow in older adults

PURPOSE: This study aimed to investigate the effect of age, posterior occlusal contacts, occlusal force, and salivary flow on masticatory performance in older adults. MATERIALS AND METHODS: The study sample consisted of 328 independently living people over the age of 60 years. Masticatory performance was determined by the concentration of dissolved glucose obtained from test gummy jellies, which are the standardized food developed for measuring masticatory performance. Bilateral maximal occlusal force in the intercuspal position was measured with pressure-sensitive sheets. Stimulated whole saliva was collected using the mastication method. Subjects were grouped into 3 categories by posterior occlusal contacts according to the Eichner Index. RESULTS: The multiple linear regression analysis showed that, with other variables controlled, masticatory performance was significantly associated with posterior occlusal contacts (beta = -.24, P < .001 for Eichner group B; beta = -.52, P < .001 for Eichner group C), occlusal force (P = .28, P < .001), and hyposalivation (beta = -.08, P < .046) (R(2) = 0.49). Within the groups classified by the Eichner Index, occlusal force was significantly associated with masticatory performance; however, age was not. For salivary flow rate, hyposalivation had a significant relationship with masticatory performance in group C (P = .003) and group B (P = .047), but no significant relationship in group A. CONCLUSION: A decline of posterior occlusal contacts, occlusal force, and hyposalivation appear to be associated with masticatory performance with aging in older adults.     

Relationship between oral function and occlusal support in denture wearers

Patients with removable partial dentures or complete dentures do not demonstrate masticatory function to the same level as patients with a full set of natural teeth. The purpose of this study was to characterize the relationship between reduction of masticatory function, in terms of masticatory performance and bite force, and the existence of remaining natural occlusal supports as assessed by the Eichner index. One hundred and eighteen removable partial denture and complete denture wearers were selected for analyses. These subjects were divided into four groups depending upon the number of occlusal supports. Seventy dentate subjects with full occlusal support were designated as a comparison group. Bilateral bite force was measured at the first molar region in all subjects. Masticatory performance was assessed using the modified Masticatory Performance Index. Peanuts were used as the test food. Both bite force and masticatory performance were significantly associated with group classification. Moreover, both bite force and masticatory performance of the four denture groups were significantly reduced compared to the comparison group and this tendency was remarkable for the denture groups without occlusal support. These results suggest that the existence of functional tooth units may be a key factor in preservation of masticatory function.     

Masticatory performance in older subjects with varying degrees of tooth loss

Objectives

The purpose of this study was to establish the factors influencing the masticatory performance of older subjects with varying degrees of tooth loss and associated numbers of posterior occlusal contacts.

Methods

The subjects consisted of 1274 independently living people aged 60 years and over. Individuals with partially or fully edentulous arches without a denture replacement or those having any symptoms related to an oral problem were excluded from the study participants. Masticatory performance, maximal occlusal force and stimulated whole saliva were measured. Subjects were grouped into three categories by posterior occlusal contact, according to the Eichner Index. Group A had contacts in four support zones; group B had one to three zones of contact or contact in the anterior region only; and group C had no support zones at all, although a few teeth could still remain.

Results

The masticatory performance in groups B and C was found to be 81% and 50% of that of group A, respectively. The multiple linear regression analysis showed that in all the groups, occlusal force was significantly associated with masticatory performance. In groups A and B, the number of residual teeth was significantly associated with masticatory performance, whereas in group C, it had no significant relationship with masticatory performance. Salivary flow rate had a significant correlation with masticatory performance only in group C.

Conclusions

Declines in occlusal contact, occlusal force and salivary flow appear to be associated with reduction of masticatory performance in older adults. However, the crucial factors for masticatory performance varied, depending on the phase of occlusal collapse.     

Tooth loss and prosthodontic rehabilitation among 35- to 44-year-old Iranians

Summary  This study aimed to investigate the frequency of tooth loss and the magnitude of prosthodontic rehabilitation based on socio-demographic information among 35- to 44-year-old Iranians. Data ( n  = 8240) were collected by 33 examiners as part of a national survey using WHO criteria for sampling and clinical diagnosis. Gender, age, place of residence and level of education served as socio-demographic information. The number of teeth, functional dentition (subjects with 20 or more teeth) and prosthodontic rehabilitation were used as clinical variables. The chi-square test and logistic regression analysis were the methods of statistical evaluation. Of all subjects, 3% were edentulous. Of dentate subjects, 3% had 1–9 teeth, 21% had 10–19 teeth, 37% had 20–24 teeth and 39% had 25–28 teeth. In total, 76% of dentate subjects enjoyed a functional dentition. Among dentate subjects, 11% of the men and 16% of the women had prosthodontic rehabilitation with higher figures ( P  < 0·001) among women, older subjects and urban residents. Having a functional dentition was more likely among those with higher levels of education [odds ratios (OR) = 1·8, 95% confidence intervals (CI) = 1·6–2·1]. Women (OR = 2·4, 95% CI = 1·8–3·0) and urban residents (OR = 2·4, 95% CI = 1·8–3·3) were the most likely groups to have prosthodontic rehabilitation. Having prosthodontic rehabilitation was more likely among those lacking a functional dentition (OR = 6·0, 95% CI = 4·8–7·6). The greatest unmet treatment needs were found among those without a functional dentition. Functional dentition should be set as a primary oral health goal among working-age adults.     

Discrepancy between satisfaction with mastication, food acceptability, and masticatory performance in older adults

PURPOSE: The purpose of this study was to investigate the relationship between self-assessed satisfaction with mastication and food acceptability and masticatory performance in a large sample of older adults with various occlusal statuses. MATERIALS AND METHODS: The subjects were 708 community-dwelling, independently living elderly persons (351 men and 357 women) with a mean age of 66.0 (SD: 4.2) years. Satisfaction with masticatory function and food acceptability (apples, grilled beef, and hard rice crackers) were evaluated using questionnaires. Masticatory performance was determined using test gummy jellies developed for measuring masticatory performance. Subjects were grouped into 3 categories by posterior occlusal contacts according to the Eichner Index. The Kruskal-Wallis test and a multiple logistic regression analysis for dissatisfaction with masticatory function were conducted. RESULTS: Overall, posterior occlusal contacts, food acceptability, and masticatory performance were associated with satisfaction with masticatory function when evaluated with bivariate analysis. Multiple logistic regression analysis showed that the number of foods that could be eaten without difficulty was the most important explanatory variable for dissatisfaction with masticatory function (P < .01). In contrast, objective masticatory performance was not significantly associated with dissatisfaction with masticatory function (P = .057) after controlling for posterior occlusal contacts and food acceptance. CONCLUSIONS: The subjective masticatory function was associated not only with objective masticatory performance, but also with an individual's posterior occlusal contacts.     

Temporomandibular joint involvement in rheumatoid arthritis, systemic lupus erythematosus and systemic sclerosis

The aim of the present study was to estimate the prevalence of temporomandibular joint (TMJ) symptoms and clinical findings in Albanian patients with rheumatoid arthritis, systemic lupus erythematosus and systemic sclerosis. The authors examined 124 consecutive hospitalized patients (88 with rheumatoid arthritis, 22 with systemic lupus erythematosus and 14 with systemic sclerosis) and 124 age- and gender-matched healthy controls using a questionnaire and an oro-facial clinical examination for assessing the presence of TMJ sounds, pain in the TMJ area, tenderness of masticatory muscles and limited mouth opening. Significantly more patients (67%) reported TMJ symptoms than controls (19%). A significantly higher proportion of patients (65%) exhibited clinical signs of temporomandibular dysfunction compared with controls (26%). The most frequent findings in rheumatoid arthritis were temporomandibular sounds and pain. Pain was found in a significantly higher proportion in patients with systemic lupus erythematosus compared with controls. Difficulty and limitation in mouth opening were observed in the majority of systemic sclerosis patients, and in only a minority of rheumatoid arthritis patients. This study supports the notion that TMJ examination should be encouraged in the rheumatology setting and clinicians should be able to provide pain management and patient support.     

Non-surgical treatment of sports-related temporomandibular joint disorders in basketball players

Abstract –  In this study, 18 basketball players (11 female, seven male; age range 14–32 years) with temporomandibular joint (TMJ) problems who had a history of sport injuries related to head or jaw region were evaluated and the results of the treatment were presented. A standardized functional examination of the masticatory system was performed including measurement of maximal jaw movements, recording of joint sounds, pain on movement of the jaw as well as tenderness to palpation of the both TMJ or masticatory muscles. Patients were also evaluated periodontally. Diagnosis was made according the criteria, described by Okeson, and appropriate treatment was applied using different kind of splints. At the end of treatment only one patient continued with right TMJ reduction with slight pain. Except for that patient, none of the patients had pain after treatment. The maximum opening of the jaws and the maximal jaw movements were statistically increased after treatment. Patients with TMJ problems also showed periodontal problems, most likely due to inadequate oral hygiene because of the limited jaw movements and pain. Periodontal parameters including probing depth (PD), Plaque index (PI), and Sulcus Bleeding Index (SBI) improved after treatment. Sports-related TMJ injuries may result in complex problems such as pain, TMJ sounds, limitation in maximal jaw movements and maximum opening of the mouth, difficulty in chewing. With the appropriate diagnosis this could be treated non-surgically in 6–8 months. This study also showed that the TMJ disorders may cause periodontal problems, which may affect all teeth and also the general health of the athlete.     

Masticatory performance in postmaxillectomy patients with edentulous maxillae fitted with obturator prostheses

PURPOSE: Oral cancer develops frequently in older populations. In Japan, the incidence of oral and pharyngeal cancer is 9,201 per year, with such tumors accounting for 1.74% of all cancers. Although obturator prostheses play an important role in the rehabilitation of postmaxillectomy patients, clinicians sometimes experience difficulty in placing obturator prostheses in edentulous maxillae, and criteria for the objective evaluation of treatment outcome have yet to be established. The present study aimed to investigate postsurgical factors influencing the masticatory performance of postmaxillectomy patients with edentulous maxillae fitted with obturator prostheses. MATERIALS AND METHODS: The extent of the hard palate defect, status of the mandibular dentition, mouth-opening distance, and maximum occlusal force were investigated, and masticatory performance was measured using a testing gummy jelly in 27 postmaxillectomy patients with edentulous maxillae fitted with obturator prostheses. The influence of these items was evaluated quantitatively, and theoretical masticatory performance for each subject was calculated using multiple-regression analysis (quantification method type 1). RESULTS: Although average masticatory performance was almost equivalent to that of healthy, independent older patients with occlusal support classified as Eichner C, considerable individual variation was noted among subjects. The order of strength of influence on masticatory performance was identified by category weight: extent of hard palate defect > status of posterior mandibular teeth > maximum occlusal force > mouth-opening distance. A relatively high correlation (R2 = 0.78, P < .01, Pearson correlation coefficient) was evident between theoretical and actual values. CONCLUSION: Masticatory performance could be predicted by evaluating postsurgical factors in patients with edentulous maxillae fitted with obturator prostheses.     

Prevalence of mandibular dysfunction in young adults.

A sample of students (739) were questioned and examined for symptoms and signs associated with mandibular dysfunction. The most frequently mentioned symptoms were headache, TMJ sounds, and pain in the face or neck. No significant differences were found between men and women with symptoms other than headache. The most common dysfunctional signs were dull occlusal sounds on repeated, firm closure of the teeth, tenderness of muscles in the jaw or head, and sounds on condylar movement. Women had a higher prevalence of these signs. Subjects who were aware of bruxism (7.9%) were more likely to have tenderness of the masseter muscle and limited mouth opening. Limited mouth opening was associated with dull occlusal sounds, pain on opening the mouth, and sounds in TMJs. Headaches were associated with tenderness in muscles and joints. Subclinical signs associated with dysfunction occurred more frequently than did awareness of symptoms.     

Factors affecting masticatory performance of Japanese children

Aim.  The aim of this study was to analyse occlusal parameters and body variables to examine the factors accounting for masticatory performance of Japanese children in relation to adults.
Methods.  Sixty-six children and 24 adults chewed three pieces of a colour-changeable chewing gum, separately, for 30 s, 60 s, and 90 s. The colour change was measured at 30 s using L * a * b * colour space system. Biting force, occlusal contact areas, and occlusal pressure were recorded by Dental Prescale. Number of strokes, and the height and weight of the subjects were included in the statistical analysis.
Results.  Within each sample, Student's t -test revealed significant differences among a * values at the three chewing times in which the value of a * (indicator of red) increased as the length of chewing time increased ( P  < 0.05). Multiple regression analysis showed that the rate of mandibular movement in preschool children has a significant impact on masticatory performance ( P  < 0.05). In schoolchildren, the rate of mandibular movement, biting force, and body weight were significant factors ( P  < 0.05). In adults, occlusal contact area, biting force, and the rate of mandibular movement were the significant factors ( P  < 0.05).
Conclusion.  Factors affecting masticatory performance differ according to the developmental stage of the individual.     

牙列咬合特征与颞下颌关节紊乱综合征关系研究

目的    研究牙列咬合特征对颞下颌关节紊乱综合征（TMDs）的影响。方法    选择2013年11月至2014年11月于大连医科大学附属第二医院口腔科就诊患者及自愿参加本研究的学生共126例作为研究对象,按照有无TMDs症状分为阴性（28例）和阳性（98例）两组。根据颞下颌关节紊乱病双轴诊断（RDC-TMD）轴1诊断标准进行颞下颌关节（TMJ）检查,取牙列模型,对两组模型前牙覆牙合、前牙覆盖、后牙覆牙合覆盖和Spee曲线等4种主要的咬合特征进行测量,结果运用SPSS13.0软件进行分析。结果    正畸治疗史对于TMDs的发生并无显著影响（P > 0.05）;而前牙覆牙合、覆盖对TMDs发生均有一定影响（均P < 0.05）,后牙反牙合、锁牙合对TMDs症状无明显影响（P > 0.05）。无论左侧还是右侧,TMJ出现杂音者的同侧Spee曲线曲度均较TMJ无杂音者的同侧Spee曲线曲度明显减小,差异均有统计学意义（均P < 0.05）;TMJ肌肉群扪诊疼痛与否对Spee曲线曲度的影响均无统计学意义（均P > 0.05）。结论    前牙覆牙合、覆盖异常可能是TMDs发生的危险因素之一;TMJ出现杂音与Spee曲线的曲度有显著相关性,当Spee曲线较平直时,TMJ杂音的发生率相对较高。     

����ҧ������������ؽ������ۺ�����ϵ�о�

??Objective    To identify differences in occlusal features between subjects with signs and symptoms of temporomandibular disorders and asymptomatic subjects. Methods    126 subjects who consented to participate in this research were examined for signs and symptoms of TMDs according to the guidelines of RDC-TMD. In addition??occlusal measurements were performed for all subjects on plaster models. The 126 patients were divided into the TMDs group and the no-TMDs group. Four occlusal features were recorded for each patient??overbite??overjet??posterior crossbite and the curve of Spee. All statistical analyses were performed with SPSS 13.0. Results    Significant associations were revealed between the curve of Spee and TMJ sounds. There were statistically significant differences between the TMDs group and the no-TMDs group in the overjet and overbite of inciors. No differences were found between subjects with and without a history of orthodontic treatment. The curve of Spee is not associated with pain of muscular origin or the posterior crossbite. Conclusion     The abnormal overjet and overbite could be occlusal risk factors for TMDs. Subjects with TMJ sounds tend to have a faltter curve of Spee compared to subjects without TMJ sounds.     

Factors associated with masticatory performance in community-dwelling older adults: A cross-sectional study

BackgroundDecreased masticatory performance leads to deterioration of overall health among older adults. However, maintaining and improving masticatory performance in ways other than maintenance of natural teeth and appropriate prosthodontic treatment remains unclear. If the factors related to the mixing and shearing abilities for masticatory performance are clarified, it may be possible to maintain and improve the masticatory performance of older adults. We aimed to clarify the association among mixing ability, shearing ability, and masticatory performance-related factors.MethodsOf the 707 community-dwelling older adults in Kusatsu Town, Japan, 344 who had been treated for any dental defects were enrolled in this study. Masticatory performance was evaluated on the basis of mixing ability and shearing ability. The number of natural teeth and artificial teeth, occlusal force, tongue pressure, and oral diadochokinesis /ta/ were measured as masticatory performance-related factors. Their relationship with mixing ability, shearing ability, and masticatory performance-related factors was examined by means of Spearman rank correlation coefficient and path analysis.ResultsAmong masticatory performance-related factors, the number of natural teeth, occlusal force, and tongue pressure were directly associated with both mixing ability and shearing ability. Moreover, mixing ability was also directly associated with shearing ability.ConclusionsTongue pressure, which can be improved by means of training, is a masticatory performance-related factor associated with both mixing and shearing abilities.Practical ImplicationsTraining for tongue pressure after proper prosthetic treatment may provide an effective means of maintaining and improving masticatory performance in older adults.     

Correlation of the characteristics of temporomandibular joint and tooth contact sounds

In this study tooth contact sounds have been compared with temporomandibular joint (TMJ) sounds elicited during opening and closing movements. One hundred and eight subjects were instructed to open as far as possible and then close with sufficient force to produce a tooth contact sound. At least four cycles from each subject were recorded on tape, The first and last sounds in the recording were the tooth contact sounds, these were identified automatically. The mean duration and rise time of each tooth contact sound was calculated and their standard deviations for each subject were calculated to give a measure of the reproducibility. The number and mean amplitude of TMJ sounds occurring during tooth separation were also calculated for each cycle. Highly significant correlations were found between the number and amplitude of the TMJ sounds within a cycle and the duration and rise time, and particularly their standard deviations. Acoustic quiescence during the open–close cycle was associated with short, reproducible tooth contact sounds characterized by a short rise time. The longest and most variable tooth contact sounds were associated with TMJ sounds in all three phases of the open–close cycle. This supports previous clinical findings associating occlusal interferences with TMJ dysfunction.     

Occlusal tooth wear in Chinese adults with shortened dental arches

To assess associations between occlusal tooth wear and shortened dental arches (SDA) in Chinese 40 years and older subjects. From a sample of 1462 urban and rural adults, those presenting with SDA (n = 150) were compared with a control group of 65 randomly selected subjects with complete dentitions (CDA). Occlusal wear was assessed using a modified Smith and Knight index – the occlusal tooth wear index (OWTI) – and analysed using multivariate (logistic) regression. There was no significant effect from SDA on severe occlusal wear (OTWI score 3 or 4: OR = 2·016; 95% CI = 0·960–4·231; P = 0·064). Higher age was associated with severe occlusal wear (P values ≤0·007) and with higher mean OTWI scores; urban had less often severe occlusal wear than rural residents (OR = 0·519; P = 0·008). Higher mean OTWI scores were associated with rural residents, except for anterior teeth. Females had lower mean OTWI score for anterior teeth (effect = ?0·153; P = 0·030). Premolars in SDA had higher mean OTWI scores compared with those in CDA (effect = +0·213; P = 0·006). In SDA, more posterior occluding pairs (POPs) were associated with lower mean OTWI sores for anterior teeth (effect: ?0·158; P = 0·008) and higher scores for molars (effect: +0·249, P = 0·003). Subjects with SDA or CDA presented comparable occlusal wear, but premolars in SDA tend to have higher probability for having occlusal wear. Fewer numbers of POPs were associated with more wear in anterior teeth.     

Constancy of clinical signs in patients with mandibular dysfunction

Repeated clinical examinations were performed 6 weeks apart on 34 patients with mandibular dysfunction to estimate the consistancy of clinical signs. The clinical examination of the patients included the masticatory muscles, the temporomandibular joint (TMJ) and the mandibular movement capacity. The clinical dysfunction index (Di) was calculated as a measure of the degree of mandibular dysfunction. The highest agreement between examinations was found for maximal mouth opening and protrusion. The agreement for palpation tenderness of the masticatory muscles and TMJ, limited movement of the TMJ, TMJ sounds, and pain during movement was considerably lower. The lowest agreement within 6 weeks was found for the clinical dysfunction index. No statistically significant difference could be detected between the two examinations for any of the clinical signs, as a result of given information and counseling before the 6-week period. It was concluded that all clinical signs, except maximal mouth opening and maximal protrusion, showed low consistancy.     

Flexure deformation in temporomandibular joint disk displacement without reduction may predict treatment outcome

To identify whether the direction of disk flexure deformation predicts the prognosis in cases of anterior disk displacement without reduction of painful temporomandibular joint (TMJ), the relationship between the direction of flexure, observed on pseudodynamic magnetic resonance (MR) images, and the outcome of conservative treatment using a flat occlusal splint was analysed in 40 female patients who perceived occasional or constant pain at unilateral TMJ with disk displacement without reduction. From the MR findings, 20 patients were classified as having upward flexure deformation of the disk and 20 as having downward flexure deformation. Patients' TMJ pain, masticatory muscle pain, amount of maximal mouth opening, and MR findings were evaluated before treatment. All patients were treated with a flat occlusal splint for 6 months. The patients' signs and symptoms were analysed statistically within each group before treatment and 3 and 6 months afterwards, and were also compared between the upward and downward flexure groups. There was no statistical difference between the groups before treatment, except in the amount of maximal mouth opening and the extent of disk displacement. The upward flexure group had persistent TMJ pain and tendency of delayed alleviation of masticatory muscle pain compared with the downward flexure group, although maximal opening gradually increased in both groups. Thus, the direction of the flexure in deformation of the disk, which can be observed only with pseudodynamic MR imaging, may predict the prognosis of painful disk displacement without reduction following treatment with a flat occlusal splint.     

Occlusal contact area, occlusal pressure, bite force, and masticatory efficiency in patients with anterior disc displacement of the temporomandibular joint

The occlusal contact area, occlusal pressure, bite force, and masticatory efficiency were measured in 48 patients with anterior disc displacement (ADD) of the temporomandibular joint (TMJ). The results were compared with those of 30 normal controls without TMJ dysfunction. The values of occlusal contact area, bite force, and masticatory efficiency measured in patients with ADD were significantly smaller than those measured in the controls, although there was no difference in occlusal pressure between the two groups. The results of the measurements of 22 patients with ADD with reduction were also compared with those of 26 patients with ADD without reduction. There was no difference in any measurement between these patients subgroups. The analysis of occlusal contact area, bite force, and masticatory efficiency appeared to be useful methods in documenting the fact that masticatory function was impaired in patients with ADD of the TMJ.     

Relationship between pattern of masticatory path and state of lateral occlusal contact

Summary  The purpose of this study is to clarify whether the state of occlusal contact on lateral excursion is related to the pattern of masticatory movement path. The masticatory movement during mastication of softened chewing gum and the occlusal contact on lateral sliding of the mandible by 1 mm (L1), 2 mm (L2) and 3 mm (L3) were recorded in 50 healthy subjects. The path of masticatory movement was classified into one of seven patterns. The number of teeth involved in the occlusal contact in each pattern was investigated and compared among different lateral occlusal positions. The occlusal contact was then classified into 15 types based on one or a combination of the following four regions; incisal region, canine region, premolar region and molar region. The number of occlusal contact type for each pattern was investigated and compared among patterns. The number of teeth involved in occlusal contact decreased as the degree of lateral excursion increased, and significant differences were observed among the lateral occlusal positions ( P  < 0·001). The occlusal contact tended to decrease in the molar region and increase in the canine or premolar regions as the degree of the lateral excursion increased. When comparing among patterns, significant differences were observed at L2 and L3 (L2; P  < 0·001, L3; P  = 0·030) but not at L1 ( P  = 0·318). The difference was remarkable at L2. It was suggested that the state of occlusal contact at L2 and L3, particularly at L2 was related to the masticatory path pattern.