Responsiveness of methods to evaluate chewing ability after removable partial denture treatments.

Abstract

The ability of an instrument to detect a clinically important change in patient-reported outcomes following prosthetic treatment is critical for its use in clinical practice and research settings. This study aimed to examine the responsiveness of instruments in evaluating patient perception of chewing ability after removable partial denture (RPD) treatment in a prospective cohort. A single 100-mm visual analogue scale (VAS), 20-item food intake questionnaire (FIQ) and 6-point chewing difficulty scale (CDS) were administered to 248 partially edentulous patients to evaluate chewing ability pre- and post-RPD treatment. We conducted a statistical comparison between the pre- and post-treatment scores and determined the effect size (r) of RPD treatment for the instruments. A significant improvement in chewing ability after RPD treatment was identified by VAS and CDS (P<.05), but not by FIQ (P=.16), which identified an improvement after controlling for sex, age, the number of missing teeth and presence/absence of existing removable dentures. The effect size was medium for VAS (r=.54), weak for CDS (r=.14-.17) and absent for FIQ (r=-.09). The increase in r was significantly associated with impaired chewing ability before treatment (ρ=-0.87, P<.001). These results suggest that the 100-mm VAS, followed by CDS, is the most responsive instrument to detect an improvement in chewing ability after RPD treatment. Pre-treatment impairment of chewing ability was associated with better responsiveness of the instruments.