Botulinum toxin type A is widely used in medicine and dentistry.18-20 The main action of BoNT-A is the inhibition of acetylcholine secretion in neuromuscular junctions, which leads to thetransient paralysis of the muscles.21 In the facial area, especially incleft lip scars, the tension of orbicularis oris muscle is the key factor in causing hypertrophy of the scar. Continuous activation of thismuscle during chewing, speaking, or expressing emotions causes increased skin tension within the wound edges, which promotes fibroblast proliferation and excessive deposition of collagen fibers in thenewly formed tissue