Initial Microgaps at Implant-Abutment Interface of Cad-Cam Abutments Fabricated by Two Different Milling Strategies and Machines (In Vitro Study)

Introduction: The micro gaps at Implant-Abutment interface can be colonized by bacteria affecting the remodeling of the peri-implant crestal bone and the long-term health of the peri-implant tissues. Aim of the study: To compare microgaps at the implant-abutment interface of CAD/CAM abutments fabricated using different milling machines and strategies. Materials and methods: Three different types of abutments were be used in the study, Milled Abutments by Arum CAD/CAM system, Milled abutments by Emmar CAD/CAM system, and Stock Abutments. Each abutment type (n=6) was torqued into the corresponding implants. Stereomicroscope and scanning electron microscope were used to make micrographs perpendicular to IAI. An image processing program was used to measure the initial microgaps at IAI. Statistical analysis was done using one-way ANOVA followed by Tukey pairwise test. Results: Data were collected, tabulated, and statistically analyzed using appropriate test. . Emmar abutments had microgaps of 1.26 µm (SEM) and 2.24 µm (stereomicroscope), similar to stock abutments at 1.25 µm (SEM) and 2.22 µm (stereomicroscope). Arum abutments showed larger gaps at 2.51 µm (SEM) and 5.56 µm (stereomicroscope). IAI microgaps differed significantly (p < 0.05) in both analyses. Conclusion: Emmar-milled abutments matched stock abutments in microgaps, while Arum-milled abutments had larger microgaps. Emmar-milled and stock abutments showed no significant difference but had smaller microgaps than Arum-milled.