Five Year Survival following Restoration of Shortened Lower Dental Arches

Removable partial dentures used to restore the shortened lower dental arch may adversely affect the remaining natural teeth and are associated with a low prevalence of use. Objective: To report the findings for prosthesis survival 5 years after restoration of lower shortened arches with bilateral cantilever resin-bonded bridges (RBBs) and conventional partial dentures (RPDs). Design: Randomised controlled trial. Setting: Secondary care. Methods: 25 male and 35 female subjects of median age 67 years were randomly allocated to RBB and RPD treatment groups of 30 patients each matched for age and sex. Interventions: Bilateral cantilever RBBs restoring one occlusal unit, up to but not beyond the second premolar, and conventional free-end saddle RPDs with cast metal frameworks. Using defined criteria, survival or failure of prostheses was noted at each review (3m and then yearly) or as and when problems arose. The unilateral failure of one RBB indicated treatment failure for that patient. Results: 21 subjects (12 RBB and 9 RPD) were lost to follow up at 5 years (5 deceased; 9 withdrew through illness and 7 for personal or other reasons). Survival analysis (modified Kaplan-Meier) indicted mean survival times of 51.3m (95% CI 42.0, 60.5m) and 42.2m (95% CI 33.3, 51.3m) for RBB and RPD groups respectively. Bridges had a slightly lower hazard rate (and were thus more likely to survive) than dentures but the difference was not statistically significant (hazard ratio = 0.62 with 95% CI: 0.28, 1.34). Conclusion: In terms of survival at 5 years, RBBs are at least as effective as RPDs for the restoration of shortened lower dental arches. Supported by the NHS Executive, UK.