Factors Affecting Implant Surface Roughness and Platform Alterations After Implantoplasty: An In Vitro Study Simulating Different Clinical Scenarios

Purpose: To determine which clinical factors might affect the postimplantoplasty presence of residual threads, platform alterations, and level of surface roughness.
Materials and Methods: A total of 60 implants were placed in 20 resin models (10 edentulous maxillary models and 10 partially dentate mandibular models), and 5-mm peri-implant bone defects were created. These models were then placed in simulation mannequins. A single researcher performed the implantoplasties, which were divided into the following groups: favorable situation (FS; maxillary incisors without adjacent teeth), unfavorable situation (US; mandibular molars with adjacent teeth), crown (C; mandibular premolars with a prosthetic crown and adjacent teeth), and noncrown (NC; mandibular premolars with adjacent teeth and without a prosthetic crown). The presence of residual threads, gaps in the implant-abutment interface, and silicone debris was assessed using a scanning electron microscope (SEM), and the surface roughness (Sa and Sz) was analyzed with a confocal optical microscope. A descriptive and bivariate analysis was conducted.
Results: The postimplantoplasty surfaces were significantly smoother than the original implant surfaces. The surface roughness was significantly higher in the US group than in the FS group. Gaps in the implant-abutment interface were infrequent (6.67%; 95% CI = 2.62 to 15.93) and only appeared in the posterior zone. The odds ratio for the presence of residual threads and silicone debris (US group vs FS group) was 7.1 (95% CI = 4.15 to 12.14; P < .001) and 5.53 (95% CI = 3.21 to 9.53; P < .001), respectively. When a prosthetic crown was present, residual threads were 7 times more likely to be found (OR = 7.0; 95% CI = 3.5 to 13.99; P < .001).
Conclusions: Implantoplasty leads to a significant reduction in the surface roughness of implants but is affected by several variables. Performing implantoplasty on posterior mandibular implants with adjacent teeth seems to be more challenging compared to implants placed in the anterior region of a fully edentulous maxilla. The presence of a prosthetic crown should also be considered as a relevant factor. Furthermore, implantoplasty can sometimes cause gaps in the implant-abutment interface and an accumulation of silicone debris, especially in areas with limited access.