In Vitro Characterization of Original and Nonoriginal Implant Abutments

Purpose: In addition to original componentry, clinicians can choose to restore an implant using third-party parts claimed to be compatible with the original implant system. The goal of these in vitro experiments was to evaluate the performance of a selection of original and clone titanium abutments available for a widely used implant system with an internal conical connection. Materials and Methods: Six groups of original and clone abutments compatible with NobelActive implants were compared based on the following parameters: dimensional accuracy, gap formation, circumferential strain, abutment screw preload, micromotion, abutment settling, median fatigue limit (MFL), and bacterial leakage. Each parameter was analyzed separately and compared with the original (reference) abutment applying a variety of statistical tests (alpha = .05). Results: Overall, the results obtained in the different experiments showed considerable deviation from the reference abutment. Deviations in interface geometry of the abutments were inconsistent and reached up to 56.26%. Gap measurements performed on cross sections of implant-abutment assemblies were not sensitive enough for detecting consistent differences. Development of circumferential strain at the implant shoulder reached up to 1,389.30 mu m/m. Abutment screw preload ranged from 285.25 N to 397.70 N, while micromotion at the implant-abutment interface ranged from 61.68 mu m to 79.69 mu m. Abutment settling resulting from screw fixation was greater compared with settling caused by dynamic loading, reaching up to 0.09 mm. The MFL ranged from 246.00 N to 344.00 N. All implant-abutment combinations showed bacterial leakage after 6 days of incubation. Conclusion: While clone abutments may look similar to the original component, they display considerable differences and variations in their physico-mechanical characteristics detectable by advanced testing methods. How much these differences affect reliability and longevity of the restoration's clinical performance should be investigated in clinical studies.