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ePaper created 2018-03-13, 09:28:55 | version 1.38.0
case report | Fig. 2a Fig. 3a Fig. 1 Fig. 2b Fig. 3b Fig. 1: The patient presented with gummy smile. Figs. 2a & b: Anatomical discrepancy between the length of the anterior teeth (A). Length of teeth measured by Chu’s Proportion Gauge (B). Figs. 3a & b: Thirty days post-op: Satisfactory tissue repair (A); increased length of teeth measured by Chu’s Proportion Gauge (B). Fig. 4: Persistence of complaint of gummy smile. Fig. 5: The patient presented with a uniform dehiscence of the upper lip ten days after the application of botulinum toxin. Fig. 4 Fig. 5 the persistence of the complaint of gummy smile was reported by the patient (Fig. 4). At the same consultation, botulinum toxin was applied. Prior to application of the botulinum toxin, the surface of the skin was disinfected with 70% ethyl alcohol and the oils from the area were removed, in order to avoid local infection. The points of application were marked beside each nostril. Then, local anaesthetic (EMLA, AstraZeneca) was applied with the aim of promoting comfort during the procedure. Botuli- num toxin A (BOTOX 200, Allergan) was diluted in 2 ml of saline, according to the manufacturer’s instructions, and two units injected into the predetermined sites, lateral to each nostril. After application, the patient was advised not to bend her head forwards for the first 4 hours and not to engage in physical activity for the first 24 hours after the procedure. After ten days, the patient was examined. She pre- sented with a uniform dehiscence of the upper lip (Fig. 5). No side-effects or complaints were reported. Discussion Gummy smile is characterised by the exposure of more than 3 mm of gingival tissue during smiling,1, 3, 5, 7 and it is often seen in women.10 The predominance among women can be explained by the fact that men present with a lower smile line.4, 5 Several aetiologies for gummy smile have been suggested, including vertical maxillary excess,4–6, 8, 9 delayed passive eruption,4, 6, 7, 9 hyperfunc- tion of the muscles involved in smiling6, 7, 9 and reduced length of the clinical crown of the teeth.1, 2, 7 These can occur separately or together, and determine the type of treatment to be used. In gummy smile caused by overactive muscles, bot- ulinum toxin is indicated. It is the treatment of choice for ease and safety of application, and its rapid effect, besides being a more conservative approach when com- pared with surgical procedures (myectomy or Le Fort I osteotomy).3–11 The clinical effects appear within two to ten days after the injection, and the most visible effect occurs 14 days after the injection.3, 5 This effect lasts about three to six months.3, 5, 6, 9 The action of smiling is determined by several facial muscles, such as the elevator of the upper lip, the eleva- tor of the upper lip and wing of the nose, the zygomati- cus major and minor muscles, the muscle of the angle of the mouth, and the orbicularis oris and risorius mus- cles.3–6, 8–10 Among them, the first three have a greater influence and determine the amount of lip elevation and, therefore, should be the muscles targeted by the injection of botulinum toxin. The fibres of these muscles converge at the same area, forming a triangle, and it is here that the three muscles can be targeted with a single injection. The injected toxin can spread over an area of 10–30 mm and this is its effective extent.3–5 The proposed site of injection ortho 1 2018 11