Purpose: To evaluate the clinical performance of zirconia bars with distal extensions supporting mandibular implant overdentures based on biological and prosthodontic outcomes.
Keywords: cohort study, edentulism, implant overdentures, prosthodontic maintenance, zirconia
Conflict-of-interest statement: The authors declare there are no conflicts of interest relating to this study.
Materials and methods: Fifteen edentulous patients (seven women and eight men) were included in a pilot study. Each patient received two interforaminal implants and a mandibular implant overdenture supported by a CAD/CAM zirconia bar with distal extensions, giving a total of 30 implants. The bar design, biological outcomes (implant survival and peri-implant conditions), peri-implant bone level changes recorded on a panoramic radiograph and prosthodontic maintenance (bar fracture and maintenance of the attachment system) were assessed at a 1-year follow-up.
Results: After 1 year, all 15 zirconia bars with their corresponding prostheses and implants were successfully in situ with no prosthodontic maintenance required and no biological complications. One patient showed moderate mucosal hyperplasia around the bar. The peri-implant radiographic measurements revealed a stable marginal bone level, with a mean of 0.20 ± 0.67 mm. The mean total length of the bar segments was 41.9 mm (range 35.0 to 51.0 mm), 8.6 mm (range 7.2 to 10.6 mm) of which came from the length of the distal extension, resulting in a mean increase in rigid support of 71% (range 60% to 99%). The mean distal bar connector area was 9.7 mm2 (range 6.8 to 18.7 mm2).
Conclusion: Zirconia bars with distal extensions for implant overdentures appear to be a reliable option for the prosthodontic rehabilitation of edentulous mandibles. A survival rate of 100% was observed for implants, bars and prostheses, with stable peri-implant bone levels, no biological complications and a low risk of prosthodontic maintenance being required.