Differences in comminution progress during mastication in healthy dentate and denture-wearing elderly people

Purpose: This study aimed to investigate the effect of removable denture prostheses on the comminution progress in elderly people. Methods: Twenty-two denture wearers of Eichner's classification B and C (75.1 ± 5.3 years old) and 20 young fully dentate subjects (27.6 ± 1.9 years old) participated in the masticatory examination, which used a combined test food from 5 daily food materials. Full masticatory cycles lasting until subjects needed to swallow and the half number of the cycles were adopted as masticatory conditions. Digital images of food particles under wet conditions were obtained for each bolus, and particles were analyzed by calculating the homogeneity and particle size indices. Results: The characteristic properties of the food particles were observed using a homogeneity index in the elderly denture group for half masticatory strokes. Their homogeneity index was significantly higher than that of the young dentate group. By contrast, no significant difference was observed in the indices for particles immediately before swallowing between two groups. Conclusions: The comminuted particle size before swallowing in healthy denture wearers was not significantly different from that in the natural dentate group. The comminution of the first-half process in denture wearers was typical and could be one possible focus for meal property specifications in future studies.