Plasma of Argon Cleaning Treatment on Implant Abutments in Periodontally Healthy Patients: Six Years Postloading Results of a Randomized Controlled Trial.

The aim of this randomized, match-paired, triple-blinded, controlled clinical trial was to assess the 6-year radiographic changes around customized platform-switched abutments placed according to the one abutment-one time concept, with and without plasma of argon cleaning treatment. A total of 20 periodontally healthy patients received one maxillary implant between the premolars. Immediately before stage 2 surgery and abutment connection, patients were randomly assigned to the control (cleaning protocol by steam) or test group (plasma of argon treatment). Periapical standardized digital radiographs were taken at the time of crown connection (T(0)) and at 12 (T(1)), 24 (T(2)), 48 (T(4)), 60 (T(5)), and 72 months (T(6)) after the final restoration delivery. Primary outcome measures were the success rates of the implants and prostheses and the occurrence of any technical and biologic complications during the follow-up period. Secondary outcome measures were peri-implant marginal bone level changes, bleeding on probing, and plaque score. Two patients (one in test and one in control group) dropped out at the last follow-up. Neither implant nor prosthetic complications were detected in the analyzed patients of both groups during the 6-year follow-up examinations. Radiographic analysis revealed a statistically significant higher mean bone loss in the control group than in the test group at T(2) (0.4 +/- 0.28 mm; P = .018), T(4) (0.52 +/- 0.63 mm; P = .037), T(5) (0.61 +/- 0.70 mm; P = .038), and T(6) (0.71 +/- 0.66 mm; P = .011), but not at T(1) (P = .131). From baseline to the 6-year follow-up, intragroup comparisons showed an absence of statistically significant difference in the test group (P = .08). Conversely, significant differences were found in the control group (P = .01). All implants demonstrated successful periodontal parameters, with no significant differences between groups. The results of this present study indicate that contaminant and bacterial removal from abutments in two-stage implants using plasma of argon could represent a positive strategy to minimize peri-implant bone resorption and longitudinally stabilize esthetic outcomes.