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The depressor anguli oris (DAO) muscle attaches to the corner of the mouth and the bottom of the mandible (lower jaw), just to the side of the chin. It is one of the muscles which helps make a frown. Often, patients with chronic facial paralysis from Bell’s palsy, Ramsay Hunt syndrome, acoustic neuroma surgery, or trauma, have too much activity in this muscle on the affected side of the face; the muscle becomes too strong. This increased DAO strength restricts the smile and can cause a feeling of tightness in the cheek.

What is DAO Excision?

DAO excision is a small surgical procedure that can permanently improve smile symmetry in many patients with facial paralysis. The procedure is usually performed in clinic and takes about 30 minutes. Local anesthesia is provided to numb the area. Then, a small incision is made inside the mouth (this is a scarless surgery), and fibers of the DAO muscle are identified and removed. We then place a few dissolving stitches to close the incision. Patients can eat and drink normally after the numbing medication wears off (about an hour). Most patients only require Tylenol and Ibuprofen, if anything, for postoperative discomfort. Many patients will notice an immediate improvement in smile symmetry once the mild post-procedure swelling goes away (a few days after surgery).

If you would like to schedule a consultation at the UNC Facial Nerve Center, please call 984-974-2255.

Before and after DAO Excision and BotoxBefore and After DAO and DLI Excision

DAO Excision Patient Before and After - UNC Facial Nerve Center
Patient with left Bell’s palsy before (left) and after (right) DAO excision and Botox.

Before and after DAO Excision and Botox
Patient before and after DAO excision and Botox

Patient before and after DAO Excision, Botox, and dermal filler