LAS VEGAS Dermatologists do not often think of using Botox in the lower face, but they should, Dr. Roberta D. Sengelmann said at the annual meeting of the American Society of Cosmetic Dermatology and Aesthetic Surgery.
It is possible to treat and improve perioral rhytids, an asymmetric smile, a gummy smile, and even "apple-dumpling" chin, said Dr. Sengelmann of Santa Barbara, Calif.
The key to using botulinum toxin type A in the lower face is to be extremely careful not to use too much since those muscles are used for so many different functions. Also, the botulinum toxin option probably should be reserved for patients with mild to moderate aging changes, as there are better alternatives for serious rhytids of the lower face, she said.
Botulinum toxin "is a different animal when you get below the canthus," Dr. Sengelmann said. "Volume loss and soft-tissue ptosis play a large role in the lower face, and this cannot always be remedied by botulinum toxin injections. The lower face and neck are functionally important as well.
"The goal when we are treating the lower face is to soften dynamic lines and not to completely freeze," she added.
In treating perioral rhytids, inject into the orbicularis oris. The injections should be fairly superficial, into just the first layer of what is a "very thick and robust muscle," Dr. Sengelmann said.
The injections should be given right above the vermilion border, evenly spaced, and they need to be symmetric.
She gives 13 U per injection, with a maximum of 6 U in the upper lip and 4 U in the lower lip, so there is not too much deadening of function. She advised against injecting only the upper lip because treated lips lengthen and can protrude over the lower lip.
Results in the lower face often do not last as long as treatment of the glabella because less botulinum toxin is used. Dr. Sengelmann said that her treatments of perioral rhytids usually last 23 months.
Downturned lips can be treated with injections to the depressor labii inferiorisshe gives 24 U into the mid-muscle. Radial perioral rhytids, or marionette lines, can be treated with injections to the depressor anguli oris. She does two injections per side, in the middle and lower third of the muscle, starting about 1 cm below the oral commissure and injecting 35 U per side.
Apple-dumpling chin, or a chin that gets lumpy when someone smiles or tightens their lips, is treated with an injection to the mentalis, at the mental crease, of about 5 U. "You want to be fairly inferior so you don't knock out the depressor labii, and it is a deep muscle," Dr. Sengelmann said.
Finally, patients with smiles that they don't like because they get a lot of upper gum showing can be treated with equal injections of 12 units into the levator labii superioris on each side of the nasal prominence.
Dr. Sengelmann also said that she always takes photographs before she does lower face treatments, that she marks her injection sites when she identifies the muscle before giving the actual injections, and that she often uses ice for the patients since lower face injections can be quite painful.
Dr. Sengelmann is on the advisory board and the speakers bureau for Allergan Inc., maker of Botox.
'The goal when we are treating the lower face is to soften dynamic lines and not to completely freeze.' DR. SENGELMANN