Effectiveness of lip repositioning in the treatment of excessive gingival display: systematic review and meta-analysis

Background: The objective of this systematic review and meta-analysis was to answer the questions ‘’Does lip repositioning surgery reduce the amount of gingiva exposed in the smile in individuals with excessive gingival display EGD (excessive gingival display)?’’ and ‘’Is the reduction of the amount of gingiva exposed when smiling obtained with lip repositioning surgery stable over time?’’ to evaluate the effectiveness of lip repositioning surgery for correcting EGD on smiling. Materials and Methods: A systematic structured search was carried out in five databases without data restriction. Studies reporting the degree of reduction in gingival ex-posure after lip repositioning surgery were included. Study selection, data extraction, and risk of bias assessment were performed in duplicate Results: One hundred sixty-four references were retrieved and eleven studies met the eligibility criteria. Meta-analysis demonstrated that lip repositioning surgery results in a significant reduction in the amount of exposed gingival tissue (mean difference = -3.03; confidence interval = -3.55; -2.52). In addition, the results remained stable in the evaluated follow-up periods (1, 3, 6 and 12 months). Included studies had a low risk of bias. Conclusions: Lip repositioning surgery is effective for the treatment of EGD on smiling and exhibits stable results in the evaluated periods. The study was registered (CRD42020184866) in the international prospective register of systematic reviews (PROSPERO). Keywords: Lip; Gingiva; Smiling; Lip repositioning; Excessive gingival display; Esthetic periodontal surgery