Bone loss in the anterior edentulous maxilla opposing two-implant-supported overdentures vs complete dentures: a systematic review and meta-analysis

Objective: To investigate bone loss in the anterior edentulous maxilla restored with maxillary complete dentures and opposed by mandibular two-implant-supported overdentures (2-IODs) or complete dentures. Method and materials: A systematic search was conducted using the Ovid MEDLINE, Embase, Web of Science, CINAHL, and Cochrane databases for studies investigating bone loss in the anterior edentulous maxilla with mandibular 2-IODs or complete dentures. Two reviewers assessed the eligibility of studies and risk of bias assessment was conducted according to the Newcastle-Ottawa Scale. A meta-analysis was performed using statistical software to estimate weighted mean difference in bone loss with 95% confidence interval (CI). The level of significance was defined as P value ( .05). Results: A total of 2,510 studies were identified through electronic and manual searching. Six studies were selected and compounded for quantitative synthesis of 163 patients. Bone loss in the anterior edentulous maxilla was greater with 2-IODs than with complete dentures. The total estimate of weighted mean difference between 2-IODs and complete dentures was −1.40 (95% CI −3.12 to 0.31). However, the difference was not statistically significant (P = .11). The data were heterogenous across the studies based on chi-square statistics (χ2 [df = 7] = 52.75, P .0001; τ2 = 5.53, I2 = 95.21%). In addition, the impact of implant splinting on bone loss was not significant (P > .29). None of the included studies were considered to be at high risk of bias. Conclusion: Within the limitations of the current systematic review and meta-analysis, the estimate of bone loss in the anterior edentulous maxilla was greater with 2-IODs than with complete dentures. However, the difference was not statistically significant. A well-designed randomized clinical study needs to be conducted to validate the results of this systematic review. Keywords: anterior edentulous maxilla, bone loss, combination syndrome, complete denture, implant supported overdenture, pressure