Implant abutment cleaning by plasma of argon: 5-year follow-up of a randomized controlled trial

Background: Contamination of implant abutments couldpotentially influence the peri-implant tissue inflammatory response. The aim of the present study is to assess the radiographic bone changes around customized, platform-switchedabutments placed according to the ‘‘one-abutment-one-time’’protocol, with and without plasma of argon cleaning treatment.Methods: Thirty healthy patients with thin gingival biotype(<1 mm) and history of periodontal disease received one maxillary implant each. Immediately before abutment connection,patients were randomly assigned to control group (cleaningprotocol by steaming) or test group (plasma of argon treatment).Outcome measures were: 1) success rate of implants and prostheses; 2) biologic and prosthetic complications; 3) peri-implantmarginal bone loss (MBL); 4) esthetic and periodontal parameters; and 5) patient satisfaction.Results: Neither implants nor prostheses were lost in eithergroup at the 5-year follow-up examination. Overall, both groupsshowed a slight amount of peri-implant bone loss from baselineto 5 years. A statistically higher mean MBL was found in thecontrol group compared with the test group at 6, 24, and 60months after crown connection. Nevertheless, during the entirefollow-up period, intragroup comparison demonstrated statistically significant mean MBL in the control group, but not in thetest group. The test group showed a higher mean gain at thesoft tissue margin, but not for the papilla. All implants showedgood periodontal parameters, with no significant differences between groups.Conclusion: Plasma of argon could be used to disinfect implant abutments before insertion to minimize future peri-implantbone resorption