Radiographic Evaluation of Vertical and Horizontal Fit in Single Implant Crowns Fabricated by CAD/CAM Systems: A Retrospective Study.

The implant-abutment connection is one of the most important factors for prosthesis stability. Moreover, restorations fabricated using CAD/CAM systems are more durable, marginally adaptive, aesthetically pleasing, and faster in fabrication as compared to the conventional restorations. The objective of this study was to retrospectively evaluate the outcome of framework fit in CAD/CAM milled single implant crown restorations using radiographs. Case records of 268 patients who have undergone implant placement and restoration at the Department of Prosthodontics and Implantology in a dental school in Chennai were obtained and analyzed. Intra Oral Periapical Radiographs that were taken post cementation of the crowns were examined for horizontal and vertical misfit. To minimize the sampling bias, the study was double blinded by an analyzer and a reviewer. The study reported that 47.94% (n = 128) had vertical misfit and in 52.06% (n = 139) there was no misfit. Horizontal misfit was found in 25.4% (n = 68) of the cases and was absent in 74.5% (n = 199) of implants that were restored. There was a statistical significance between misfit and the quadrant in which the implant was placed. It was observed that horizontal misfit was high in quadrant 3 with 38.7% (n = 77), followed by quadrant 4 with 31.7% (n = 63), quadrant 2 with 16.6% (n = 33) and quadrant 1 with 13.1% (n = 26). Vertical misfit was high in quadrant 3 with 38.1% (n = 53) followed by quadrant 4 and 2 with 36% (n = 50) and 15.8% (n = 22) respectively, and quadrant 1 with 10.1% (n = 14). It can be concluded that the marginal fit of CAD/CAM milled frameworks for single implant crowns showed higher vertical misfit than horizontal misfit. Horizontal misfit and vertical misfit was evident in quadrant 3.