articLe | BOTulInumTOxIn A | owing to
the anatomy of the different co-dependent
levator muscles and their
attachments in both the upper lip skin and
orbicularis oris, the risk–benefit
ratio of treating a patient with a
gingival smile is high and the potential
comorbidity significant. Figure 8 Intraoral injection of the central lip levators Dosing
To non-surgically elongate the upper lip, the central upper lip levators need to be gently relaxed (not paralysed) with injections of onabotulinumtoxinA. This can be accomplished with the patient in a sitting or semireclined position. Palpate the nasomaxillary groove with the fingertip of the index finger of the non-dominant hand, until the finger tip pad straddles the lower lateral aspect of the alar facial sulcus and the superior edge of the maxillary alveolar process. Excessive pressure with palpation in this area can cause some discomfort to the patient, so this manoeuvre should be carried out as quickly as possible. As the patient smiles with the index finger in this position, contraction of the levator labii superioris alaeque nasi can be felt. At the point of maximum thickness of the muscle, insert the needle perpendicularly to the surface of the skin and deeply into the nasofacial groove for approximately 3–5 mm. Inject
1–2 u of
onabotulinumtoxinA intramuscularly and just above the periosteum of the canine fossa. An additional unit of onabotulinumtoxinA may be required if the central lip levators are very strong and the centre of the upper lip is lifted extremely high. Remember to reserve this injection technique only for those who have an exaggerated gingival smile, and in whom the levator labii superioris alaeque nasi can be palpated.
Treatment implications when injecting a gummy smile 1Injecting the levator labii superioris alaeque nasi
can reduce exaggerated gingival show by elongating the upper lip. It will also efface the nasolabial sulcus and fold, and flatten the philtrum and attenuate the vermillion.
when it can be palpated, otherwise, adjacent, non-targeted muscles will be affected, and lip competence and symmetry compromised.
3Inject only low volumes of low doses of 30 ❚ May 2011 |
prime-journal.com onabotulinumtoxinA in the perinasal area. 2Inject the levator labii superioris alaeque nasi only Injecting onabotulinumtoxinA at this site may reduce
the height and extent of the nasolabial fold by weakening the levator labii superioris and the levator labii superioris alaeque nasi. The more laterally located lip levators, i.e. zygomaticus major and minor, levator anguli oris, and risorius, are to be avoided; otherwise, either an adynamic or asymmetric smile can result. Weakening the central upper lip levators without affecting these lateral upper lip levators allows the lateral levators uninhibited movement during a smile. This can also be enhanced by treating the depressor anguli oris with onabotulinumtoxinA, thereby removing any additional antagonistic depressor action against the lateral upper lip levators. The depressor septi nasi may require treatment with 1–2 u of onabotulinumtoxinA along the length of the columella. This will produce a more natural smile, while lowering the central aspect of the upper lip and reducing the depth of a horizontal upper lip crease and the extent of an exaggerated gummy smile. If migration of onabotulinumtoxinA extends into the superficial fibres of the orbicularis oris, an inability to fully pucker the lips will occur. Another technique is to inject 1–2 u of
onabotulinumtoxinA intraorally into the bellies of the two central upper lip levators (Figure 8) (26), by passing the needle through the gingivolabial sulcus above the alveolar ridge at the same point in the nasofacial groove and canine fossa as described above. A minimum dose of low-volume onabotulinumtoxinA should just barely relax the central upper lip levators so that the upper lip cannot fully retract upward. If the excessive gummy show is at its highest in the centre of the upper lip, then 1 u of onabotulinumtoxinA can be injected into the depressor septi nasi at the base of the columella.
Outcomes Treating patients with an exaggerated gingival smile can produce a variety of anatomic and functional changes. By limiting the exaggerated upward movement of the upper lip with injections of onabotulinumtoxinA, an obvious reduction in the amount of upper gingival and dental show will result, along with an elongation of the upper lip, a flattening of the philtrum, a thinning of the vermillion, and an effacement of the medial aspect of the nasolabial fold and sulcus.
inform the patient of the potential risks, benefits, comorbidities, and inherent functional and cosmetic changes expected when perinasal and perioral mimetic muscles are weakened.
4Before any treatment with onabotulinumtoxinA, 5 Patients with a zygomatic smile, a full
denture, or a canine smile without exaggerated gingival exposure (i.e. at least a 3mm gingival display) should not be treated with onabotulinumtoxinA injections to reduce nasolabial folds.
IMAGE BENEDETTO
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