Randomized Controlled Clinical Trial Comparing Cemented Versus Screw-Retained Single Crowns on Customized Zirconia Abutments: 3-Year Results

Purpose: To assess the biologic and technical responses to cemented and screw-retained all-ceramic single-tooth implant-supported reconstructions at 3 years postinsertion. Materials and Methods: Thirty-four patients with single-tooth implants were randomly restored with either a cemented lithium disilicate crown on a customized zirconia abutment (CEM) or a screw-retained crown with a directly veneered zirconia abutment (SCREW). At baseline examination and after 3 years of loading, marginal bone level and technical parameters were assessed. Differences in marginal bone loss were tested using Mann-Whitney U test at baseline and at 3 years, and changes within each group between baseline and 3 years were tested using Wilcoxon signed rank test. Results: The median changes between baseline and the 3-year follow-up amounted to -0.1 mm (CEM; intragroup P = .36) and -0.0 mm (SCREW; intragroup P = .58). Intergroup comparisons did not reveal statistically significant differences at 3 years (P = .20) or over time (P = .70). Conclusion: At 3 years, screw-retained and cemented reconstructions rendered largely the same radiographic and technical outcomes.