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

To synthesize the available evidence regarding lip repositioning surgery (LRS) and quantify the short- and long-term reduction in excessive gingival display (EGD) with the procedure. Additionally, evaluate the effect of myotomy on the results. Seven electronic databases were searched up to May 2020 by two independent reviewers. Studies evaluating the exclusive use of LRS to treat EGD were included. After risk of bias assessment, the data were quantitatively evaluated with random-effects meta-analysis. The initial database search yielded 368 studies, of which 16 were selected for full-text review. Finally, eight studies were included. The random effects model exhibited an EGD reduction of 2.87 mm (95% CI: 1.91-3.82) after 3 months of LRS. These results decreased after 6 months (2.71 mm; 95% CI: 1.95-3.47) and 12 months (2.10 mm; 95% CI: 1.48-2.72). Meta-analysis comparing the performance of myotomy showed greater EGD reduction at 6 months than without myotomy (P < 0.02). LRS is an effective approach for treating EGD, and it has satisfactory results up to 6 months. After this period, the effectiveness appears to progressively decrease over time indicating substantial relapse at 12 months. Myotomy seems a suitable alternative to increase the stability of LRS. Lip repositioning surgery is an effective procedure to improve smile esthetics in the short-term (up to 6 months). After this period, the efficacy of LRS seems to decrease progressively, and an approximately 25% relapse may be expected after 12 months. Clinicians should combine the procedure with other approaches, such as plastic periodontal surgeries, restorative procedures, or botulin toxin injections for more predictable and stable outcomes.