RESUMEN
Botulinum toxin is a protease used by the bacterium Clostridium botulinum that causes chemical denervation of skeletal muscles, producing a temporary weakening of muscle activity. Despite having a transitory effect, the application of botulinum toxin has been identified as an alternative for correcting an excessive gingival display (EGD). However, studies evaluating the maintenance of long-term results of botulinum toxin remain scarce. This study aimed to evaluate the effectiveness and duration of botulinum toxin type A in the treatment of anterior EGD. Botulinum toxin Type A was applied to 15 patients with EGD. The measurement was performed in triplicate, using a Castro Viejo dry point compass, between the central cervical portion of the upper lateral incisors to the lower portion of the upper lip, bilaterally. The measurements were performed before the application of the toxin and repeated on days 7, 14, 90, 120, and 180 after the procedure. The data were analyzed using repeated-measures ANOVA, followed by a Bonferroni. There was a statistically significant reduction between the measurements performed on the Baseline and seven days after the application of the botulinum toxin. After 180 days, approximately one-quarter of the patients in the sample did not presented EGD. Mild adverse effects were reported by 46.7% of the patients. The use of botulinum toxin type A was effective to treat EGD. After 180 days, it was still possible to observe a significant effect compared to the initial gingival exposure.