Relationship between Mastication and Brain Function of Partial Denture Wearers

Objectives: In this study, the effects of mastication on brain function were examined with and without a removable partial denture in partially edentulous patients. The main focus was to research improved brain function in relationship to correctly fitted dentures. Materials and Methods: Twenty partial denture wearers (aged 54-82, mean 67.6) were the subjects. They had visited Tsurumi University Dental Hospital for monthly denture maintenance. Denture maintenance was performed to ensure the best fitting of dentures for all patients. Initially, the occlusal contact area and occlusal force were measured with and without dentures for functional assessment using the Dental Prescal Occluzer (FPD-705, GC Co., Japan) and Dental Prescale 50H without a wax version (GC Co., Japan). Electroencephalograms were taken for 3 minutes after gum chewing (Xylitol dental support chewing gum, Lotte, Japan) with and without dentures and analyzed with a Diagnosis Method of Neuronal Dysfunction for brain function assessment. The statistical analysis was performed using Wilcoxon's test (ƒÑ=0.05). Results: The average occlusal contact area of the denture-wearing and non-denture-wearing group was 10.2°"5.7 mm2 and 6.6°"5.7 mm2, respectively. In addition, the average occlusal force of the denture-wearing and non-denture-wearing group was 449.1°"220.6 N and 291.5°"228.0 N, respectively. In all subjects, the denture-wearing group indicated a significantly greater occlusal area and occlusal force than the non-denture-wearing group (p<0.05). Brain function activity was significantly increased in 17 of 20 subjects (p<0.05). It was clear that the effect of partial denture usage of properly fitted dentures to improve mastication and occlusion is markedly involved in not only improved mastication but also enhanced brain function. Mastication improvement resulting from correctly fitting dentures results in the activation the activation of brain function after chewing. Conclusion: Improved mastication and brain function activation were achieved by proper fitting of dentures.