The influence of prosthetic treatments and implant-supported prostheses on posterior mandibular ridge atrophy: a retrospective cohort study.

Aims: Bone preservation is a requirement for long-term stability of dental prostheses, which is all the more important in the posterior mandible, given the particular challenges these areas pose to prosthetic treatment. The objective was to investigate the implications of different prostheses on the atrophy of posterior alveolar bone after tooth loss.

Materials And Methods: A total of 457 treatment cases were retrieved from the medical documentation and information network. Baseline panoramic radiographs taken at prosthetic delivery and follow-up radiographs (≥ 3 years post-treatment) were available for analysis, with a mean follow-up duration of 6.42 ± 2.37 years. Posterior mandibular bone height in these radiographs was compared using one-way ANOVA followed by the Tukey post hoc test for statistical analysis.

Results: Sites supporting fixed prostheses commonly used in partially edentulous mandibles exhibited less bone atrophy compared to sites with clasp- or telescope-retained removable partial dentures (RPDs) (p < 0.001). Furthermore, sites with clasp-retained RPDs and telescope-retained RPDs demonstrated less bone atrophy when distal support was present (p < 0.001). In edentulous mandibles, bar-retained overdentures supported by four implants exhibited significantly less bone atrophy compared to mucosa-supported complete dentures, bar-retained overdentures supported by two implants, or overdentures retained by Locator abutments on two implants (p < 0.001).

Conclusion: Bone atrophy in the posterior mandible should be expected to vary greatly with prosthetic designs. Long-term stability is possible with fixed partial prostheses, RPDs are less favorable in the absence of a distal support and bar-retained overdentures on four or more implants exhibited the lowest bone atrophy in fully edentulous mandibles.

Clinical Trial Number: Not applicable - retrospective analysis.