What is orthognathic surgery? 

Orthognathic surgery, otherwise known as corrective jaw surgery, is performed to correct misaligned jaws and teeth. The disproportionate jaws can be due to abnormal development (developmental) or the result of a traumatic injury. Orthognathic surgery is performed if you have jaw issues that cannot be resolved with orthodontics (braces) alone. Your orthodontist will discuss with your oral & maxillofacial surgeon to form a suitable treatment plan.

Why should I seek treatment?

You may want to consult an oral and maxillofacial surgeon if you experience:

• Difficulty chewing due to bite problems – open bite, underbite, overbite, crossbite
• Speech impairment
• Facial abnormalities - asymmetry of the jaw, protruded or retruded jaw
• Inability to make lips meet without effort
• Excessive show of upper teeth, especially when smiling
• Obstructive sleep apnoea and snoring

What should I expect?

Before the procedure

After investigations comprising x-rays, photos, and impressions of your teeth are performed, the oral and maxillofacial surgeon and orthodontist will work together to formulate suitable treatment options. Discuss with your surgeon and orthodontist to decide which treatment plan is best for you.

Treatment usually starts with braces for about 12 to 18 months to level and align your teeth in preparation for surgery. You may look worse during this pre-surgical phase. 

During the procedure 

Orthognathic surgery is performed by oral and maxillofacial surgeons under general anaesthesia.

Incisions are made inside your mouth to avoid scars on your face. However, small skin incisions may sometimes be required. The jawbones are then cut, separated, and moved to their planned positions. Titanium fixation plates and screws are then inserted to fix the jaw bones in their ideal positions. The fixation plates and screws are not routinely removed after bone healing and generally do not cause any long-term issues if left attached to the jaw.

The surgery could involve the upper jaw, lower jaw, or chin, depending on the diagnosis. Upper jaw surgery is also known as maxillary osteotomy, whereby bone above your teeth around the maxillary sinus and nasal cavity is cut, allowing the upper jaw to be mobilized.

Lower jaw surgery, otherwise known as mandibular osteotomy, is performed by splitting bone posterior to the molars bilaterally so that the teeth bearing segment can be mobilized. Chin surgery or genioplasty is performed by separating the chin from the lower jaw. These mobile segments are stabilized with titanium fixation plates and screws to allow bony healing. 

After the procedure

Orthognathic surgery takes place in a hospital and usually requires 1 to 2 days of hospitalization. The teeth will be tied shut for about 1-2 weeks to stabilize the bite. You will be followed up by your oral and maxillofacial surgeon closely for about 1-2 months before being transferred back to visit the orthodontist.

Braces will then be resumed to finetune the bite. It requires approximately 2-3 years to complete the whole treatment, and retainers will have to be worn after to maintain the bite stability. The times required for treatment as mentioned above are estimates and can differ on a case-by-case basis. 

Is orthognathic surgery safe? What are the complications and risks? 

Orthognathic surgery is generally a safe procedure. However, all surgeries are associated with some risks and possible long-term complications. Sometimes, the outcome may not meet your expectations.

The following are the possible complications and risks (not exhaustive):

• Bleeding. If blood loss is significant, a blood transfusion is sometimes required.
• Wound infection. This may appear 1 to 2 weeks after the surgery with symptoms of fever, increasing pain, swelling, and foul-smelling discharge from the wound. Contact and return to see your surgeon as soon as possible if this happens.
• Nerve injury. The nerves may be moved or stretched, resulting in numbness at the lips, chin, tongue or palate, which can be temporary or permanent. There may be facial palsy very rarely, which takes several months to recover.
• Relapse of the jaw position. This can occur soon after the surgery or some months later. If the bite is mildly affected, orthodontics can resolve the problem. Larger changes in jaw positions may sometimes require another jaw surgery.
• Damage to teeth. The bone cuts may be very close to the roots of teeth. The blood supply to the teeth may be disrupted, resulting in the need for root canal therapy. The affected tooth/teeth may have to be extracted on extremely rare occasions.
• Pain at the jaw joints. Prolonged jaw opening at the time of surgery may exacerbate pre-existing temporomandibular joint disorders and pain.
• Loosening of titanium plates and screws. Infection may sometimes cause loosening or exposure of the hardware. A second surgery may be required to remove these plates and screws.

What to expect after treatment?

Patients will be reviewed periodically following orthognathic surgery. Repeat x-rays, scans and photographs may be taken to assess the treatment outcome.