Evaluation of the design-driven prediction of removable partial denture retention

Abstract Statement of problem Removable partial dentures (RPDs) are a cost-effective treatment designed to replace missing teeth for partially edentulous patients. However, RPDs often have insufficient retention, which results in treatment failure and patient dissatisfaction. Purpose The purpose of this clinical study was to investigate the factors related to RPD retention that affect patient satisfaction, to clinically validate a newly published model for predicting RPD retention based on the number and position of missing teeth and clasps, and to identify the predictions of patient satisfaction to improve the guidelines for RPD design. Material and methods Seventy-five patients treated with 107 RPDs delivered at the McGill University Dental Clinic (Montreal, Canada) and Estaing University Hospital (Clermont-Ferrand, France) participated in this study. Data on the RPD design were collected from the clinical records, and the retention of each RPD was tested with the mathematical model designed for predicting RPD retention. Data on patient satisfaction with their RPDs were collected by using a standardized questionnaire (McGill Denture Satisfaction Instrument). Statistical analysis of factors related to RPD retention and patient satisfaction was performed by using the chi-square test and Mann-Whitney test, while the developed model for predicting RPD retention was evaluated by using sensitivity and specificity analysis. Results The average satisfaction score for all RPDs was 8.2 ±1.7 out of 10. Patients were more satisfied with RPDs in the maxillary arch, tooth-supported, or retained by ≥3 clasps than with RPDs in the mandibular arch, with distal extension bases, or retained by  Conclusions RPD retention predicted from the number and position of clasps and missing teeth might help to determine patient satisfaction. In addition, patient satisfaction with RPDs was influenced by the arch type, the presence of a distal extension base, and the number of clasps.