Comparison of Oral Health-Related Quality of Life in Partial and Complete Denture Wearers: A Propensity Score Analysis

Dentures, both partial and complete, have been shown to have the same impact on one's quality of life. Due to the impossibility of randomization in these studies, they are prone to selection bias.  This study aimed to compare the effect of partial and complete dentures on oral health-related quality of life (OHRQoL) by propensity score to overcome selection bias.  

This is a cross-sectional descriptive-analytic study. A total of 1376 people participated in this study. Age, sex, marital status, education level, smoking, smoking opium and its derivatives, and dental visit was collected by a checklist. OHRQoL was measured by the OHIP-14 questionnaire. The generalized boosted model was used to estimate the propensity score. Missing data were imputed using multiple imputations with mixed models. The assumptions of multivariable regression analysis and propensity score method were first examined, and then the quality of life related to oral health was compared between the two groups.  

The regression model's assumptions were not verified due to high skewness and collinearity. The results of the normality test (P < 0.001) and goodness fit test (P < 0.001) revealed that the regression model did not fit the data. The propensity score method reduced at least 76% of the bias resulting from the distribution difference between the confounding variables and was used for analysis. In the regression and propensity score method, the results showed that the total OHIP-14 score of the complete prosthesis group was higher than the partial prosthesis group at 3.92 (95% CI = (2.18,5.65)) and 3.64 (95% CI = (1.93,4.53)), respectively. This difference was clinically and statistically significant (P < 0.001). In addition, there is a significant difference in the two groups based on propensity in all seven areas (P < 0.001). But there is no significant difference in the regression adjustment of the Functional limitation of the two groups (P = 0.035).  

The propensity score has fewer assumptions than the regression method and may be more reliable for OHIP scores. The propensity score analysis revealed that despite the costs and repair issues associated with partial dentures, complete denture wearers have lower OHRQoL than partial denture wearers.