The Impact of Occlusal Support Patterns in Right-Handed Denture Wearers on Oral Function and Oral Health-Related Quality of Life

Background: Denture treatment for unilateral distal extension defects can cause organic and functional asymmetry in the oral cavity, which may be influenced by physical laterality and the preferred chewing side (PCS). However, existing classification systems for dental defects overlook left–right defect distribution, and individual laterality is rarely considered in treatment planning. Objective: This study investigated the relationship between dental defect location and laterality. Methods: This was a cross-sectional study of 176 right-handed elderly participants divided into five groups by denture type: control (n = 87), right distal extension (n = 9), left distal extension (n = 13), bilateral distal extension (n = 43), and complete denture (n = 24). Primary outcomes included masticatory efficiency, bite force, oral health-related quality of life (OHRQoL), and PCS assessed through interviews. Results: The right distal extension group demonstrated significantly reduced masticatory efficiency, bite force and OHRQoL compared to the control group, indicating diminished oral function and quality of life. The left distal extension group showed significant left–right differences in function, with reduced performance on the distal extension defect side. The right side was the PCS in all groups, with no significant differences in distribution observed between the control and denture groups. Conclusion: In elderly individuals with unilateral distal extension dentures, right-handed individuals demonstrate different masticatory functions based on whether the defect is on the right or left side. Additionally, when occlusal support is bilaterally maintained through prosthodontic treatment, including dentures, the impact of structural asymmetry on the PCS is limited.