DAO resection, or “smile release,” is a minor surgical procedure done to improve a tethered smile in patients with facial synkinesis, a type of facial nerve damage.
The depressor anguli oris (DAO) muscle pulls down the corners of your mouth. In some people, this muscle can be too tight, which can make their smile look uneven. DAO resection removes part of this muscle to improve smile symmetry.
What is DAO Resection?
DAO resection, also known as DAO myectomy or “smile release” surgery, is a minimally invasive surgical procedure. It is performed to improve uneven smiles in patients with facial synkinesis or nonflaccid facial paralysis.
The DAO muscle is a fan-shaped muscle that pulls the corner of the mouth downward. In people with synkinesis, the DAO can have excessive tone (meaning it’s too tight), which can tether the smile, pulling down the corners of the mouth and making smiles appear uneven or “frozen.”
DAO resection removes part of this muscle to improve smile symmetry.
Conditions we treat with DAO resection
DAO resection is a treatment for people with synkinesis or nonflaccid facial paralysis. It can help improve smile symmetry by removing part of the DAO muscle that is too tight and tethering the smile.
Why Would I Need DAO resection?
Doctors recommend DAO myectomy for people with:
- Nonflaccid facial palsy, in which muscles are tight or overactive.
- Poorly showing upper teeth when smiling.
- Sigmoid smile, in which the smile curves oddly.
Is DAO resection covered by insurance?
Yes, this procedure is covered by insurance for the treatment of facial synkinesis.
What are the Risks and Complications of DAO Resection?
As with any surgery, DAO resection has some risk of complications, but they’re rare.
Possible issues include:
- Infection.
- Seroma.
- Scar tissue at the surgical site.
Contact your doctor if you notice anything unusual or experience any problems after surgery.
What Should I Expect from DAO Resection?
This procedure is performed in the procedure clinic under local anesthesia.
- On the day of your appointment, you will have a chance to meet with a team member to ask any questions and sign the necessary paperwork.
- You may bring a support person to the appointment. However, you are also welcome to drive yourself home if you prefer, as you will be awake throughout the procedure.
- The entire appointment typically takes less than one hour.
During the DAO resection
- You will be positioned comfortably, and your lower lip will be numbed with a small lidocaine injection.
- The surgeon will make a small incision inside the cheek to access the DAO muscle. There are no external incisions or scars.
- The surgeon will locate and remove part of the DAO and the nearby buccinator muscle.
- Once the muscle is removed, several dissolving stitches are placed to close the wound.
- BOTOX® may be administered on the same day, if indicated.
After the DAO resection
- The numbing medication will last for up to two hours.
- After the medication wears off, we recommend eating a soft diet (such as ice cream, yogurt, or pudding) for the rest of the day, then resuming a normal diet the following day.
- A small amount of bruising and/or swelling is expected. Applying ice and sleeping with your head elevated on a few pillows will help decrease swelling.
- Most patients describe the pain as feeling sore and find relief by taking acetaminophen or ibuprofen.
- The dissolving sutures can take anywhere from 10 to 21 days to fully dissolve.
Recovery after DAO resection
Some patients may see an immediate improvement in their smiles. But for most patients, results are evident four to six weeks after the procedure.
- Recovery includes ice packs, gentle massage, and avoiding heavy activity for a few days.
- There might be swelling, scar tissue, or temporary trouble closing the mouth.
What’s the success rate of DAO myectomy?
Studies show that smile release surgery doesn’t just improve how the face moves. It also helps people feel more confident and appear more emotionally expressive. That can make a big difference in how they connect with others.
A 2024 study in The Laryngoscope reported that after DAO surgery, people with synkinesis said they:
- Felt better about their smiles and social interactions.
- Had more even smiles with better lip movement and more visible teeth.
- Looked happier both when smiling and at rest.
By UPMC Editorial Staff. Last reviewed on 2026-03-01.
