A randomized clinical trial of two basic removable partial denture designs. Part I: Comparisons of five-year success rates and periodontal health.

A randomized clinical trial was undertaken to compare the effectiveness of two partial denture designs, one with I-bar (bar) and the other with circumferential retainers (circumferential), in 134 patients with Kennedy class I and class II edentulous conditions. A total of 30 partial dentures were considered failures, five because of abutment failures and 25 because of the lack of removable partial denture use for eating. The 5-year success rate of 71.3% for the circumferential design did not differ significantly from the 76.6% for the bar design (p > 0.05). There were no discernible changes in the nine periodontal health components of abutment teeth with either of the two designs after 60 months. The results indicate that the two designs do not differ significantly in terms of success rates, maintenance care, and effects on abutment teeth. A well-constructed removable partial denture of either design, supported by favorable abutments and accompanied by a regular recall program offers a satisfactory treatment modality.