It is a common clinical condition, which can be caused by an abnormal dental eruption (delayed passive eruption), hyperfunction of the upper lip elevator muscle, excessive vertical growth of the maxilla bone, over-eruption of the maxillary anterior teeth, or a combination of the above described factors.
[1][2] Several treatment options have been proposed to enhance the smile display and to reduce the gingival exposure.
[3] Treatment option include orthodontics,[4] surgery (gingivectomy),[5] botulinum toxin A injections,[6] and micro-autologous fat transplantation (MAFT).
[8] The material is injected into the hyperactive muscles of upper lip, which causes a reduction in the upward movement of lip thus resulting in a smile with a less exposure of gingiva.
[9] Botox is usually injected in the three lip elevator muscles that converge on the lateral side of the ala of the nose; the levator labii superioris (LLS), the levator labii superioris alaeque nasi muscle (LLSAN), and the zygomaticus minor (ZMi).