Retrospective evaluation of implant-supported overdenture treatments: prosthetic complications

Objectives: The objectives of this work are to determine the prevalence of prosthetic complications in implant-supported overdentures, and to compare the maintenance needs of retentive bar-clip and independent abutment systems. Methods: Thirty-seven patients, with 43 implant-supported overdentures (23 maxillary and 20 mandibular) with different retention systems (bar-clip and independent abutments), were clinically evaluated. The total number of maintenance visits and their causes were taken from the clinical file of patients and were evaluated retrospectively. Statistical analysis was done with IBM (R) SPSS (R) vs.22.0 software, considering alpha = 0.05 and using Fisher exact test, Mann-Whitney test and Spearman correlation. Results: Treatments with implant-supported overdentures present a high frequency of prosthetic complications: substitution of retainers (79.1%), overdenture repair or rebasing (53.5%), gingival hyperplasia (34.9%), tightening or fractured screws (20.9%), replacement of the prosthesis (16.3%), changing of retentive system (9.3%) and infrastructure fracture (4.7%). There are significant associations with bar system for gingival hyperplasia and for replacing clips, and with location in the maxilla for replacement of prosthesis and retainers. There are no differences between retentive systems for the number of annual visits. Conclusions: Prosthetic long-term evaluation of treatment with implant overdentures can provide useful guidance to the dentist in the selection of the number of supporting implants, the retentive system and the design of the removable prosthesis. (C) 2015 Sociedade Portuguesa de Estomatologia e Medicina Dentaria. Published by Elsevier Espana, S.L.U.