Comparison of Stud- Retentor Versus Bar-Clip Attachment as Implant- Supported Systems Used in Overdentures: A Systematic Review and Meta-Analysis.

This study aimed to perform a systematic review and meta-analysis to analyze the results obtained clinically for bar-clip versus stud-retainers in overdentures. Three databases (PubMed Central, MEDLINE, and BvSalud) were used beyond a manual search. The study followed strictly the inclusion and exclusion criteria, considering the PICO strategy. For the risk of bias and quality assessment of studies, in the case of RCT, there were six domains of analysis, and for non-RCT studies, the Modified Newcastle-Ottawa Scale was performed. A meta-analysis was developed using the available data for marginal bone loss (MBL) and survival rate. 25 studies were included. The stud-retentor had the lowest implant SR (87.6%) and the greatest MBL (1.96 mm). For the bar-clip system, the mean survival rate was 95.91%, with only 4 studies included for this system, and the mean MBL was 1.13 mm. Only 3 studies directly compared both systems quantitatively, showing a significantly greater MBL toward the stud-retention group. The results may not allow determination of the best system for overdenture (stud retentor or bar-clip). Therefore, most of the studies suggested the stud-retentor as a more preferable system due to better distribution of forces, biological peri-implant behavior, low-cost, and ease for removal facilitating the sanitization and/or repair.