Some clinical investigations of the masticatory performance of complete denture wearers

Chewing efficiency and contact area discrepancies in Angle's class I and II malocclusion: A comparative study

Objective

The study aimed to assess and compare both the chewing efficiency and the contact area between class I and class II of Angle's malocclusions.

Material and methods

A total of 120 individuals aged between 19 and 30 years were examined and were divided into two groups according to Angle's class (Class I and class II). The chewing efficiency was quantified using the ViewGum software and two-colored chewing gum. The contact area was quantified using modeling wax and MATLAB software. All data were collected, then, analyzed using SPSS software 21. Data normality was checked through kurtosis test. Descriptive results were calculated. Matched sample t-tests were used to compare chewing efficiency measurements between right and left sides. Independent t-tests were used to compare chewing efficiency and the contact area between class I and class II of Angle's malocclusions. Linear regression and Pearson correlation were used to assess the correlation between chewing efficiency and the contact area. The significance level was fixed at p = 0.05.

Results

For group 1, the mean hue value on both sides was 0.086 ± 0.058. For group 2, it was 0.095 ± 0.055. The difference between both groups was statistically significant (p = 0.03). For group 1, the mean contact area was 49.91 ± 21.47 mm2. For group 2, it was 51.42 ± 19.76 mm2. The difference was statistically not significant (p = 0.4). The correlation between the contact area and the chewing efficiency in both groups was statistically significant and it was negative (in class I p = 0 and R = -0.616; in class II p = 0.01 and R = -0.408).

Conclusion

The Chewing is better for patients with Angle's Class I malocclusion. The contact area is higher. Larger occlusal contact area leads to higher masticatory efficiency. Further studies should be conducted.

Use of handgrip strength measurement as an alternative for assessing chewing function in people with dementia

Background

Chewing ability and handgrip strength can be independent explanatory factors of physical fitness. The usability of measurement procedures for assessing chewing function in people with dementia seems to be limited. This study aimed to show an association between handgrip strength and chewing function to enable the use of handgrip strength measurement as an alternative for determining chewing parameters in people with dementia. 

Methods

The data analysed here are part of the OrBiD (Oral Health, Bite Force and Dementia) pilot study. A total of 120 participants were assigned to five evaluation groups based on their cognitive abilities using the Mini-Mental State Examination (MMSE). The MMSE groups in this data analysis were “no dementia” (noDem, MMSE 28–30), “mild cognitive impairment” (mCI, MMSE 25–27), and “mild dementia” (mDem, MMSE 18–24). Handgrip strength, maximum occlusal force, and chewing efficiency were measured. 

Results

The Mini-Mental State Examination scores among all participants (n = 71) resulted in a median of 27 and a range of 18–30. An association between maximum handgrip strength and the cognitive impairment of the participants was shown. Nevertheless, the use of handgrip strength measurement as an alternative for determining chewing function was not verified in this study.

Conclusions

The feasibility and reliability of chewing function measurements in people with dementia should be investigated. Existing measurement procedures may need to be adapted or new assessments may need to be developed to be usable in people with dementia.

Trial registration

ClinicalTrials.gov NCT03775772.

A prospective cross-over study to evaluate the effect of two different occlusal concepts on the masseter muscle activity in implant-retained mandibular overdentures

BACKGROUND

The purpose of this prospective cross-over study is to evaluate the effect of bilateral balanced occlusion and canine guidance occlusion on the masseter muscle activity using implant-retained mandibular overdentures.

METHODS

After evaluation of 12 completely edentulous patients using cone beam computed tomography (CBCT), mucoperiosteal flaps were reflected exposing the mandibular interforaminal region. Two implants were placed in the interforaminal region for each of the 12 patients. After a healing period of 3 months, acrylic maxillary complete dentures and mandibular overdentures were fabricated with bilateral balanced occlusion for 6 patients and canine guidance occlusion for the other 6 patients. Electromyographic evaluation of the masseter muscles, during clenching on a silicon index and chewing peanuts and cake, was conducted on the patients after using their dentures for 4 weeks. Each occlusion concept was then converted into the other concept using the same dentures, and the procedure of evaluation was repeated after 4 weeks. The recordings were analyzed statistically using Wilcoxon signed ranks test. p < 0.05 was considered statistically significant.

RESULTS

The highest electromyographic activity of the masseter muscles was recorded during clenching on a preformed silicon index followed by chewing peanut then cake for both occlusal concepts. The recordings of the masseter muscle associated with canine guidance occlusion were higher than bilateral balanced occlusion but with no statistically significant difference except between the right masseter muscles during clenching (p = 0.042*).

CONCLUSIONS

Both bilateral balanced occlusion and canine guidance occlusion can be used successfully in implant-retained mandibular overdentures without affecting masseter muscle activity.

Can dentures improve the quality of life of those who have experienced considerable tooth loss?

OBJECTIVES

The aim of this study was to identify variations in the impact of oral health on quality of life (OHQOL) among UK residents in relation to self-reported number of teeth possessed and denture status. In addition, to determine whether recourse to a removable prosthesis for those who claimed that they had experienced considerable tooth loss (having <20 teeth) was associated with quality of life.

METHODS

The vehicle for this was the Office for National Statistics Omnibus survey in Great Britain. A random probability sample of 2667 addresses was selected in a multistage sampling process. Participants were interviewed about their oral health status. The impact of oral health on quality of life was measured utilising the OHQoL-UK(W) measure.

RESULTS

The response rate was 68%. Variations in OHQoL-UK(W) scores were apparent in relation to self-reported number of teeth possessed (P < 0.001) and denture status (P < 0.001). Moreover, disparities in OHQOL were apparent among those who experienced considerable tooth loss who didn't have recourse to a denture (P < 0.001). In regression analysis, those who claimed that they had <20 natural teeth but had no recourse to a denture were less than half as likely to enjoy enhanced oral health related quality of life compared to others in the population (OR = 0.46, 95% Cl 0.30, 0.71), controlling for socio-demographic factors.

CONCLUSIONS

Experience of considerable tooth loss without recourse to a removable dental prosthesis is an important predictor of oral health related quality of life, as captured by OHQoL-UK(W), and associated with reduced quality of life.

Oral bolus kneading and shaping measured with chewing gum

A masticatory test using two-colored chewing gum is presented and analyzed. Two separate parameters of chewing were studied on the same chewing gum bolus after 10 strokes of oral preparation, color mixing, and bolus shaping. The two parameters were evaluated in indices 1-5. A test series should preferably contain three chewing gums, and color mixing can be evaluated on six sides and shape-indexed for each bolus. The medians characterize the subjects' masticatory ability. Color mixing may relate, for example, to ensalivation of the food during chewing, and bolus shape may relate to preparation into a form suitable for swallowing. The tests were used on test subjects with different dental and denture status. Significant differences in both color mixing and shape indices were found between groups with different status. The method is discussed in relation to earlier types of tests, e.g., the comminution test mostly used hitherto.

The relationship of drug use to denture function and saliva flow rate in a geriatric population

This study investigated an "old elderly" population and the relationships between the use of hyposalivatory drugs and denture function, including saliva flow rates and denture-supporting structures and health. There was a high prevalence of drug use and medical problems. Hyposalivatory drugs were prescribed for more than half of the subjects. There was a significant relationship between increased hyposalivatory drug use and reduced saliva flow rates. Reduced values for denture-supporting structures were found to be related to increased medical problems and hyposalivatory drug use. Reduced values for denture-supporting tissue health were found to be related to masticatory performance and retention and stability. Bite force showed a strong positive relationship with masticatory performance. Some of the subjective evaluations by the subjects showed statistically significant relationship with their respective objective measures: perceptions of dry mouth were related to saliva flow rates, perceptions of denture rocking or looseness were related to retention and stability ratings, and reports of pain on chewing were related to masticatory performance. It may be concluded that the use of drugs with hyposalivatory side effects may have a deleterious influence on the denture-bearing tissue. Direct influence on denture function, however, was not found. These findings provide valuable insights into the effects of drug usage in old age and their impact on oral health and denture function. Diagnostic and treatment capabilities are thus enhanced in that physicians, pharmacists, and other health-related professionals can be alerted to the problems accompanying hyposalivatory drug use. This may permit alternatives in medication when possible, and dentists may more effectively plan and conduct prosthodontic care for these individuals.(ABSTRACT TRUNCATED AT 250 WORDS)