Subjective assessment of chewing function of obturator prosthesis wearers

PURPOSE: Assessments of masticatory performance and occlusal force for wearers of obturator prostheses were performed as clinical objective assessments and reported in an earlier study. The purpose of the present study was to evaluate clinically the chewing function of obturator prosthesis wearers by self-evaluations and to examine their relationship to the objective assessments. MATERIALS AND METHODS: Twenty patients with maxillofacial obturator prostheses who were having a periodic checkup at the maxillofacial rehabilitation clinic in Kyushu University Hospital were recruited for this study. Chewing function was evaluated by 3 assessment tools: a self-assessment mastication scale, a chewing function score, and a mastication score. In addition, correlations among these assessments and objective tests--ie, masticatory performance and maximum occlusal force--were analyzed by the Spearman rank correlation coefficient. RESULTS: The mean self-assessment mastication scale was 63.2 (SD 31.8), the chewing function score was 54.0 (SD 30.2), and the mastication score was 51.4 (SD 33.3). There was no statistically significant relationship between the self-assessment mastication scale and each objective test. However, there were significant correlations between each semisubjective score--the chewing function score and the mastication score--and masticatory performance. There was no relationship between each semisubjective score and maximum occlusal force. CONCLUSION: A self-assessment mastication scale was not always in agreement with objective assessments, and assessments made by patients should be taken into consideration when arranging maxillofacial rehabilitation. Conversely, both chewing function and mastication scores corresponded with masticatory performance, and these would be useful as screening tests before performing objective tests.     

Selection of occlusal scheme on masticatory function in denture wearers

The characteristics of full balanced occlusion (FBO) and lingualized occlusion (LO), which are occlusions that make up removable dentures, were investigated from the standpoint of masticatory function, and an attempt was made to clarify criteria for selecting and configuring occlusions to suit individual cases. Since there have been few studies that have quantitatively compared FBO and LO from the aspect of masticatory function, we decided to organize and present the characteristics of both in this paper based on our findings from studies carried out in our department. We found that LO offered a higher ability of food crushing, showed higher masticatory performance in the case of hard foods, displayed faster as well as smoother masticatory movement, and showed chewing patterns that were closer to the chopper type compared with FBO. Moreover, subjective evaluation by subjects indicated that "it was easier to eat and the food tasted better" with the LO compared with the FBO in the case of general foods. Furthermore, a comparison of anatomical form and bladed form of upper lingual cusps in the case of LO showed no difference between the anatomical form and the bladed form in terms of masticatory performance in the case of any of the test foods, but the bladed form offered a higher ability of food crushing, displayed faster and smoother masticatory movement, and showed chewing patterns that were closer to the chopper type. In addition, subjective evaluation by subjects showed that it was easier for them to eat raw carrots and pickled radish, which are hard foods generally thought to be difficult to eat with dentures, with the bladed form compared with the anatomical form.     

The effect of chewing exercise in preschool children on maximum bite force and masticatory performance

International Journal of Paediatric Dentistry 2012; 22: 146–153 Background. Mastication is a developing function affected by various factors. There is a need for further research on methods of promoting masticatory function in young children. Aim. The aim of this study was to evaluate the effects of gum chewing exercise on the maximum bite force (MBF) and the masticatory performance of preschool children. Design. The study population included 98 preschool children age 4–6 years. MBF was measured by Occlusal Force‐Meter^®, and masticatory performance values were evaluated by using the colour‐changeable chewing gum. The examinations were performed four times with an interval of 4 weeks. An exercise group of 70 subjects was instructed to chew the exercise gum twice daily for 5 min during a 4‐week period. The chewing gum used for this study was specially developed with the physical property of maintaining hardness during chewing. A control group of 28 subjects was instructed not to chew any gum during the study period. Results. No significant differences were found between the exercise group and the control group in MBF and a* values at the start of the study. After 4 weeks of chewing exercise, MBF and a* values were significantly increased in the exercise group compared with those of the control group. These increases were maintained for 4 weeks after exercise had finished. Conclusions. Gum chewing exercise is effective to increase MBF and a* values of preschool children and the effects are maintained after exercise completion.     

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

PURPOSE

To assess function by identifying changes in swallowing and masticatory performance in maxillary obturator prosthesis wearers.

MATERIALS AND METHODS

Sixty 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%.

RESULTS

Profile, 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).

CONCLUSION

Swallowing ability was significantly improved after wearing obturator but masticatory performance was not significantly different from those having similar occlusal support zone in their dentition.     

Association between masticatory performance and maximal occlusal force in young men

The purpose of this study was to examine the relationship between masticatory performance and maximal occlusal force in dentate subjects, using test foods of varying hardness. Subjects were 20 young males with natural dentitions. Gummy jellies with two different degrees of hardness have been used as test foods to evaluate masticatory performance. Masticatory performance was evaluated by the increase of the surface area of expectorated pieces of comminuted gummy jelly that was calculated from the concentration of gelatin. Maximal occlusal force was measured with pressure sensitive sheets (DENTAL PRESCALE 50H R type). The results suggested that maximal occlusal force had a significant positive correlation to the masticatory performance both with soft gummy jelly and hard gummy jelly. The correlation coefficient (r) with hand gummy jelly tended to be larger than with soft gummy jelly.     

Electromyographic evaluation of masticatory function in denture wearers in related to existing occlusal support

The aim of this study was to clarify the relationship between partially edentulous pattern and the masticatory function in removable partial denture wearers. Eighty eight removable partial denture wearers and 7 subjects with intact dentition volunteered for this study. Using the Eichner's index, all subjects were divided into 6 groups. Electromyographic (EMG) activities of the masticatory muscle were recorded during chewing a piece of raw carrot. The masticatory function was analyzed by using the variation coefficient (VC) of the time parameter of EMG interval recorded during mastication. The association of the VC with group classification based on Eichner's index was analyzed using analysis of covariance with gender and age as the covariates. The result of the analysis revealed that the VC was significantly associated with group classification and the patients in groups without posterior occlusal supports exhibited significantly higher VC values than those in groups with posterior occlusal supports. These findings suggested that the reduced function in patients without the posterior occlusal contacts was difficult to attain improved and satisfactory outcome with removable partial dentures and that there is a significant need for posterior occlusal support for the preservation of 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.     

Influence of periodontal treatment on objective measurement of masticatory performance

In a previous study, we evaluated the influence of periodontal treatment and physiological parameters on the subjective perception of mastication using the Oral Impact on Daily Performance Questionnaire (OIDP). In this study, we investigated the influence of periodontal treatment on the objective measures of masticatory performance in the same study sample. Patients with chronic periodontitis (n = 28) were examined on two occasions with a 45-day interval. Electrical activity of the masticatory muscles and maximum bite force were determined. In addition, masticatory performance was assessed using silicone impression blocks as test material. The median particle size of the chewed blocks was determined employing a sieving method. The number of teeth and the probing depth were also recorded. The probing depth was significantly reduced following treatment (P < 0.001). The median particle size of the chewed material was also reduced, which indicates a significant improvement in masticatory performance after treatment (P < 0.001). Bite force and muscle activity were significantly correlated both before and after treatment (P < 0.05). There was a negative correlation between masticatory performance and number of teeth (P < 0.05); moreover, individuals with a lower number of teeth exhibited poorer masticatory performance (P = 0.01). Periodontal treatment had a positive influence on masticatory performance 45 days after conservative treatment.     

Association of symptomless TMJ sounds with occlusal force and masticatory performance in older adults

Summary  This study investigated associations between temporomandibular joint (TMJ) sounds and occlusal force or masticatory performance stratified by posterior occlusal supports in older Japanese adults. The subjects consisted of 1646 independently living people over 60 years. Masticatory performance, occlusal force, TMJ sounds and maximal mouth opening were examined. Posterior occlusal supports were classified by the Eichner Index. The prevalence of TMJ sounds was 27·7%, limitation of mouth opening (<40 mm) was 7·9% and TMJ pain was only 1·5%. In the Eichner C group, TMJ sounds were significantly associated with lower occlusal force (OR = 3·20, P  = 0·046) and lower masticatory performance (OR = 3·18, P  = 0·041) after controlling for gender and age. These associations were not found in the Eichner A and B groups. Within the limitations of this study, the presence of TMJ sounds, even if they were symptomless, was associated with impairment of masticatory function in older adults with reduced occlusal support.     

总义齿咬合平面定位对最大咬合力的影响

为观察总义齿咬合平面定位设计与患者咀嚼功能的关系，选择１０名无牙颌患者，分别为每个患者各作４副总义齿，其中有一副义齿（标准义齿）的咬合平面以上中切牙近中切角为基准或向后上、或向后下、或向左右方向倾斜５°。测定患者戴各义齿用单侧尽最大力咬合时的力值，发现患者戴标准义齿时平均最大咬合力值显著高于其它义齿。该结果提示：总义齿的咬合平面平分颌间距离且与耳屏鼻翼线平行最有利于无牙颌患者咀嚼功能的发挥     

Quality of life and masticatory function in denture wearers

Successful prosthodontic treatments for a patient with removable partial dentures including maxillofacial prostheses hopefully brings about psychological wellbeing as well as improved health. The purpose of this study was to investigate the relationship between quality of life (QOL) and the various aspects of denture function. At first, a questionnaire with a visual analog scale with 16 question items concerning denture and/or eating problems, the present state of health, psychological and physical wellbeing, life satisfaction, and QOL was developed. To discuss the validity and reliability of the questionnaire, 48 outpatients who wore a denture were asked to fill it out. Next, to discuss the difference in QOL of the patient with various kinds of dentures and conditions, 103 outpatients were asked to complete the newly developed questionnaire. The questionnaire which contained four factor areas with eight questions for denture patients was developed by factor analysis with Varimax rotation. The reliability of the QOL scale was confirmed by reliability analysis (Cronbach's alpha = 0.784). The QOL score of edentulous patients with a complete denture having some trouble chewing was significantly lower than that of other denture patients. It was suggested that the wearing of a denture significantly affected the QOL of elderly persons.     

Reliability of a two‐colour chewing gum test to assess masticatory performance in complete denture wearers

The aim of this study was to test the reliability of a method to measure the masticatory performance of complete denture wearers employing a colour‐mixing ability test and assessment by visual and electronic colourimetric analysis. A sample of 75 subjects was selected from patients who received new conventional complete dentures. Masticatory tests were performed using a two‐colour chewing gum that was masticated for 5, 10, 20, 30 and 50 chewing cycles, performed in a random order. The mixing level of the two colours of the chewed gum was assessed visually by two independent raters based on a 5‐point ordinal scale. The specimens were flattened into a 1‐mm‐width wafer, scanned and saved as a two‐sided digital image. Each pair of images was submitted to an electronic colourimetric analysis to assess the level of colour mixture, measured by the circular variance of hue (VOH ). Overall inter‐ and intra‐rater agreements in visual analysis were 64% and 68%, respectively (almost 99% of scores ranged within ±1 point), whilst overall weighted kappa was >0.80. A proportional increase in the level of mixture occurred with increased number of chewing cycles (P  < .001). Similarly, VOH and the visual analysis were highly correlated (r = ?.89; P  < .001). Bland‐Altman plots revealed excellent agreement and extremely low systematic error between duplicated VOH measures. It was concluded that the two‐colour chewing gum test is a reliable method to assess the masticatory performance in complete denture wearers using both visual and electronic colourimetric analyses.     

Assessment of masticatory performance by geometric measurement of the mixing ability with 2-color chewing gum

Statement of problemThe 2-color mixing ability test has been recently introduced for objective assessment of masticatory performance. However, the ideal bicolor specimens have not yet been identified, and the color analysis of digital images requires improvement.PurposeThe purpose of this clinical study was to formulate a custom-made, 2-color chewing gum for the mixing ability test and to develop an image-processing method for color mixing analysis.Material and methodsSpecimens of red-green (RG) chewing gum were prepared as a test food. Twenty dentate participants (10 men, 10 women; mean age 21 years) took part in this study. Each participant masticated 1 piece of RG gum for 3, 6, 9, 15, and 25 cycles, and this task was repeated 3 times consecutively (total n=15 for each participant). The boluses were retrieved and flattened to 1-mm-thick wafers and scanned with a flatbed scanner. The digital images were analyzed using ImageJ software equipped with a custom-built plug-in to measure the geometric dispersion (GD) of baseline red segment. The predictive criterion validity of this method was determined by correlating GD to the number of mastication cycles. The hardness and mass of RG chewing gum were measured before and after mastication. Hardness loss (%) and mass loss (%) were then calculated and compared with those of a commercially available chewing gum.ResultsThe 2-way repeated-measures ANOVA with post hoc Bonferroni test showed that GD was able to discriminate among the groups of different numbers of mastication cycles (P<.001). Pearson correlation coefficient confirmed the significant correlation between GD and the number of mastication cycles (r=0.90, P<.001). The hardness loss and mass loss of RG chewing gum were significantly lower than those of commercial chewing gum (P<.001).ConclusionsThe newly formulated chewing gum provides an appropriate test food material for masticatory performance assessment. The new image-processing method discriminated among the different levels of color mixture and quantified the mixing ability.     

A test for occlusal function. The value of a masticatory efficiency test in the assessment of occlusal function

A sample consisting of 50 adult subjects aged between 21-23 years was assessed for their masticatory ability, by the use of a masticatory efficiency test. The occlusal status was assessed from study models using five occlusal indices. The scores obtained from the masticatory efficiency tests were correlated to those obtained from the occlusal analyses, using a correlation coefficient test. Significant correlations were found between the two scores. A multiple regression analysis was used to predict the masticatory efficiency from the occlusal scores. The findings revealed that only a small proportion of the masticatory efficiency could be predicted. This suggested that factors other than those used in these indices may have an effect on the masticatory efficiency.     

A study on the measurement of occlusal force and masticatory efficiency in school age Japanese children

Aim. The purpose of this study was to investigate the relationship between occlusal force and masticatory efficiency in school age Japanese children.
Sample. The subjects were 208 volunteer Japanese children from 7 to 9 years old. Occlusal force was measured using an MPM-3000 occlusal instrument and masticatory efficiency by adenosine bisodium triphosphate (ATP) particles.
Results. It is obvious from the results that the occlusal force of Japanese school age children is decreasing. A t -test of both masticatory efficiency and occlusal force showed no significant sex differences for children at 7 and 8 years old. However, 9 year-old boys showed significantly higher values compared with 9 year-old girls in both measurements. No significant difference was seen between 7 and 8 year-old children in both measurements. However, 9 year-old children showed significantly higher values when compared with 7 and 8 year-old children. Occlusal force and masticatory efficiency were shown to be correlated with chronological age, with a coefficient of more than 0·6.     

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.     

Influence of static and dynamic occlusal characteristics and muscle force on masticatory performance in dentate adults

Masticatory performance is the outcome of a complex interplay of several factors. This study was carried out to determine the relationship between masticatory performance and several muscular-related and occlusion-related factors in a population with a full or near-full complement of natural teeth. One-hundred dentate young adults participated in this cross-sectional study. Maximum muscular force with jaw, hand, tongue, and cheek were measured by means of a gnatodynamometer. Occlusal contact area and number of teeth in contact were determined in the maximal intercuspal position and in a 1.5-mm right and left lateral excursion by means of interocclusal registrations that were scanned and analysed using image software. Masticatory performance was determined by sieving the Optosil particles resulting from 20 chewing cycles. Stepwise multiple linear regression analysis showed that the maximum bite force in the region of the first molar had the best correlation with masticatory performance and explained 36% of its variation. Static occlusion characteristics such as occlusal contact area, the lack of lateral crossbite and the number of anterior teeth in contact explained an additional 9% of the variation in masticatory performance. These findings suggest that variables related to dynamic occlusion or tongue or cheek force do not enhance the prediction of masticatory performance.