Retrospective study comparing the clinical outcomes of bar-clip and ball attachment implant-supported overdentures

The aim of this study was to compare the clinical outcomes of implant-supported overdentures (ODs) with either bar-clip or ball attachments. The implant, prosthesis failure, and technical complications were the outcomes analyzed in this retrospective clinical study conducted in a specialty clinic. Seventy-five patients with 242 implants supported by 76 ODs (36 maxillary, 40 mandibular) were included in the study and followed up for 88.8 ± 82.9 months (mean ± standard deviation). Bar-clip and ball attachments were used in 78.9% and 21.1% of the cases, respectively. Forty-three implant failures (17.8%) in 17 prostheses (17/76; 22.4%) were observed in this study. The average period of implant failure was 43.3 ± 41.0 months, and most of them were maxillary turned implants. The bar-clip system demonstrated more complications in the attachment parts compared to the ball attachment system. Poor retention of the prosthesis was similar between the two systems. Loss of implants resulted in the failure of 10 ODs in this study. ODs opposed by natural dentition or fixed prostheses presented with more complications. The Cox proportional hazards model did not show a significant effect on prosthesis failure for any of the factors. These findings indicated that patients with ODs need constant maintenance follow-ups to address the technical complications and perform prosthodontic maintenance regardless of the attachment system used