Mandibular implant-supported overdenture: A systematic review and meta-analysis for optimum selection of attachment system

AIM: This systematic review aimed to compare different attachment systems used in mandibular implant supported overdentures by assessing outcomes such as prosthodontic maintenance and complication, peri implant tissue changes, retention, and patient satisfaction for optimum selection of attachment system. SETTINGS AND DESIGN: This systematic review conducted following Preferred Reporting Items for the Systematic Review and Meta Analysis (PRISMA) guidelines. MATERIALS AND METHODS: A systematic electronic literature search was conducted through PubMed, The Cochrane Central Register of Controlled Trials (Central), and Science direct. A hand search was also performed for individual journals and reference lists of selected studies. Randomized controlled clinical trials and crossover clinical trials from 2010 to 2020 with follow up of more than 1 year were included. The Cochrane Collaboration's tool was used for assessing the risk of bias of included studies. STATISTICAL ANALYSIS USED: The statistical meta analysis was performed using Review Manager (RevMan) [computer program]. Version 5.4. Copenhagen: The Nordic Cochrane Centre, The Cochrane Collaboation, 2020. RESULTS: Six studies that met the inclusion criteria possess the low risk of bias with follow up of more than 1 year were included in this systematic review. Out of four outcomes, meta analysis was performed for prosthodontic maintenance and peri implant tissue changes. Due to the limited availability of data, retention and patient satisfaction were reviewed systematically without meta analysis. The result of meta analysis for ball versus magnet attachment showed statistically significant differences in prosthodontic complications and maintenance, and ball attachment reported fewer complications than the locator attachment (risk ratio [RR] =0.55, confidence interval [CI] =95%, P = 0.03). Peri implant tissue changes were analyzed in the included studies as probing depth and marginal bone loss. The result of meta analysis for probing depth showed no statistically significant difference between bar versus telescopic type of attachment (RR = 0.20, CI = 95%, P = 0.74). The meta analysis results for marginal bone loss showed no statistically significant difference between bar versus telescopic type of attachment (mean difference = 0.35, CI = 95%, P = 0.10). CONCLUSION: It can be concluded from the current review that bar attachment provided the most superior retention. The telescopic attachment system not only showed the most favorable patient's satisfaction but also reported the least peri implant mucosal changes. The ball attachment system is a favorable choice for limited inter arch space and parallel implant placement.