Duration of effectiveness of Botulinum toxin type A in excessive gingival display: a systematic review and meta-analysis

Abstract

Botulinum toxin type A is effective in reducing excessive gingival display caused by hyperfunctional upper lip elevator muscles; however, this effect is transient. This study aimed to determine the duration of the effectiveness of botulinum toxin type A on a gummy smile. A systematic search was conducted using Medline (PubMed), Scopus, and Web of Science electronic databases, from 1970 to March 2017 with no language restriction; the search included studies evaluating adult patients with excessive gingival display who were treated with botulinum toxin and were followed-up for at least 3 months. OpenGrey and Clinical Trial Registry were also consulted. Quality assessment was applied to determine the level of evidence and bias, and a meta-analysis was performed. Of 2181 full texts, 71 were obtained, with 3 prospective studies meeting the selection criteria. The gingival display was significantly reduced to baseline with 2, 4, and 8 weeks of treatment. The gingival display considerably reduced at the baseline-2-week comparison (-4.44 mm using raw data and-4.05 mm using the standard difference) and increased throughout the weeks of follow-up. There is scant evidence to determine the duration of the effectiveness of toxin type A on a gummy smile. The effect tends to be stable until at least 8 weeks of follow-up, and the gingival exposure may not return to baseline within 12 weeks of follow-up. Well-designed randomized clinical trials with a minimum of 6 months of follow-up are necessary to strengthen the evidence.

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

“…On the other hand, when the discrepancy involves a nondentoalveolar etiology other approaches are necessary. In these cases, treatment could consist of orthognathic surgery, 9 botulin toxin injections, 10 lip repositioning surgery, 2,11 or the combination of therapies.…”

Uso de la toxina botulínica en el tratamiento de sonrisa gingival

“…Chagas et al 11 y Pedron et al 12 afirman que existen varios procedimientos que pueden ser realizados para la corrección de la sonrisa gingival como: gingivoplastía, intrusión de dientes por medio de aparato ortodóntico, cirugía ortognática y resección ósea, los cuales están disponibles para reducir la sonrisa gingival. No obstante, esos tratamientos son altamente complejos y costosos.…”

Retrospective analysis of off‐label medication use at a plastic surgery hospital in China andevidence‐basedevaluation

“…In addition, Comparison results showed that increasing the number of injection points per side did not seem to lead to an improved aesthetic outcome. 45 A system review found that the effect tended to be stable until at least 8 weeks of follow-up, and the gingival exposure might not return to baseline within 12 weeks of follow-up. 45 Short-term adverse events such as asymmetric smile and difficulty in smiling were present solely in the first weeks following initial treatment.…”