Radiographic Evaluation of Marginal Adaptation, Framework Overhangs and Residual Cement in Implant-supported Fixed Prostheses

Marginal gaps, overhanging frameworks and residual cement result in plaque accumulation, finally leading to peri-implantitis. The aim of this study was to radiographically evaluate marginal adaptation, residual cement and overhanging frameworks in implant-supported fixed prostheses. In the present descriptive/cross-sectional study, 96 implant-supported fixed prostheses fabricated and delivered in Tabriz Faculty of Dentistry underwent radiographic examinations using the paralleling technique. The radiographs were scanned, saved on a computer and analyzed with Digimizer software program in relation to marginal adaptation, framework overhangs and residual cement. Data were analyzed with descriptive statistics (frequencies, percentages, means and standard deviations) using SPSS 21. The results showed mean marginal gaps of 119.32±113.96 and 205.53±214.02 μm in single-unit and multi-unit fixed prosthesis, respectively; 43.7% and 53.4% of single-unit and multi-unit restorations, respectively, did not exhibit good marginal adaptation. In addition, 53% of samples had no overhangs, and 11.5%, 11.5% and 24% had overhangs only at the mesial, only at the distal and on both aspects, respectively. There was no cement around the prostheses on any radiograph. Half of the prostheses evaluated exhibited framework overhangs. In addition, there was inadequate marginal adaptation in approximately one-third of the prostheses. No residual cement was detected around any of the prostheses.Half of the prostheses had framework overhangs and there was inadequate marginal adaptation in one-third of them.