Non-Surgical Management of the Gingival Smile with Botulinum Toxin A. A Systematic Review and Meta-Analysis.

Abstract

Due to its aesthetic implications, gummy smile is a common reason for consultation. When it is caused by a vertical excess of the maxilla, the ideal solution is orthognathic surgery. However, in borderline cases and when the cause is hyperactivity of the upper lip levator muscle complex, alternative conservative solutions can be considered, such as the application of botulinum toxin A (BTX-A). The main objective of this systematic review and meta-analysis is to analyze the effectiveness of BTX-A in the treatment of gummy smile in short and medium term, to study its stability and to evaluate potential complications. A thorough search of the PubMed, Scopus, Embase, Web of Science and Cochrane databases and a grey literature search were conducted. The inclusion criteria were: studies with a sample size greater than or equal to 10 patients with gingival exposure greater than 2 millimeters in smile, treated with BTX-A infiltration. The benefit of BTX-A in terms of improvement of gummy smile is demonstrated, a statistically significant reduction in gummy smile is estimated by BTX-A therapy two weeks after its application. Its results gradually decrease over time, however they remain satisfactorily without returning to their initial values ​​after 12 weeks.