Micro-CT Analysis of Microgap at a Novel Two-Piece Dental Implant Comprising a Replaceable Sleeve In Vitro

Purpose: Microcomputed tomography (micro-CT) is a relatively new modality to investigate mechanical deformations. The purpose of this study was to assess the microgap at the implant-sleeve connection of a new two-piece dental implant with a replaceable sleeve. Materials and Methods: Implants were assembled with 25-degree angulated abutments. Micro-CT was used to assess implant-sleeve connection gaps under the following mechanical conditions: (1) unloading; (2) compressive 10,000 cyclic loading with 400 N; (3) static compressive load of 200 N or 400 N for 24 hours. Results: The mean gap in the unloaded sample was 2.9 +/- 0.9 mu m. The mean gap difference after cyclic compressive load was 0.3 +/- 0.15 mu m, demonstrating a negligible effect for the cyclic loading. Under static compressive load, there was no increase in microgap size at 200 N. At 400 N, a significant (P < .05) increase was noted. While the mean values increased by 1.9 mu m, the most pronounced significant increase in mean microgap was noted in the direction of force application (5.1 +/- 2.14 mu m), while a significant decrease in mean microgap (1.2 +/- 1.47 mu m) was noted on the opposite side. Conclusion: The mechanical behavior of the implant-sleeve connection under static and dynamic loads was found to be within the previously reported range of implant dentistry.