Factors Associated with Masticatory Performance in Kennedy Classification II Removable Partial Denture Wearers

Objective: Masticatory performance of denture wearers is outcome of the intricate interrelationships between patient and denture-related factors. This study aimed to identify factors associated with masticatory performance of Kennedy classification II removable partial denture (RPD) wearers. Methods: Forty-two participants (28 females and 14 males, mean age 62.7± 6.3 years) with a shortened dental arch restoring with Kennedy classification II RPD were included in the study. The condition of all RPDs was functionally accepted by experienced prosthodontist at data collection. Masticatory performance was determined by chewing test with standard two-colored wax cubes using Mixing Ability Index (MAI). The variables evaluated were patient factors: gender, age, natural functional tooth units, maximum bite force, restored arch (upper/lower), conditions of opposite arch dentitions, height and shape of residual ridge, and qualities of ridge mucosa, and denture-related factors: total functional tooth units after restored, denture type (acrylic/metal framework) and design (unilateral/cross-arch). The data were analyzed by linear regression analysis. Results: MAI of patients ranged from -3.06 to 0.80 (Mean -0.76, SD 0.92). Multivariate regression analysis (adjusted R²=0.45) revealed that male gender (P<0.001) and natural functional tooth units (P=0.02) were positively associated with MAI, i.e. better masticatory performance. Maximum bite force also showed a significant relationship with MAI, but only in the univariate analyses. None of the denture factors had significant influence on MAI. Conclusions: (1) Masticatory performance of patients with functionally acceptable RPD is influenced primarily by patient factors. (2) In distal extension RPD wearers, maximum bite force may not the main factor affected masticatory performance. Maintenance of higher number of natural tooth units prior to distal extension RPD construction is recommended for better masticatory performance.