This study was carried out to evaluate the efficacy of poly(lactic acid) and poly(glycolic acid) (PLA/PGA) resorbable membranes in conjunction with autogenous bone grafts when used for the treatment of implant dehiscences and/or fenestrations. Nine patients with a total of 18 implants participated. Nine implants were associated with dehiscences, and 9 with fenestrations; 16 implants were in the maxilla, and 2 in the mandible. Nine defects were treated with PLA/PGA membranes (test gorup), and the nine were treated with expanded polytetrafluoroethylene (e-PTFE) membranes (control group). Second-stage surgery was performed after 6 to 7 months of healing. Overall results of the regenerative therapy of the 18 defects showed a highly significant (P .001) defect reduction, with a 93.38% (SD = 15.88) bone fill. A slightly higher percentage of bone fill was found in the e-PTFE group (98.20%) than in the PLA/PGA group (88.56%), but the difference was not statistically significant (P = .207). This study demonstrated that resorbable PLA/PGA membranes can be equally effective as e-PTFE in the treatment of implan t dehiscences and fenestrations when associated with au togenous bone chips.