What is it?

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 or the result of a traumatic injury. Orthognathic surgery is usually done in conjunction with orthodontic treatment to harmonise the jaw relationship and improve the bite (occlusion).

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

• Difficulty chewing when the upper and lower teeth do not meet – open bite, underbite, overbite, crossbite
• Unclear speech
• Asymmetry of the face
• Inability to make lips meet without effort
• Excessive show of upper teeth especially when smiling
• Facial defects
• Obstructive sleep apnoea and snoring

• Prognathic jaw occurs when the lower jaw is overdeveloped and protrudes beyond the upper jaw
• Retrognathic jaw is a receding lower jaw, sometimes called a weak chin
• An 'open bite' leaves space between the upper and lower teeth when the mouth is closed

Does the whole treatment take a long time? What are the stages involved?

After investigations comprising x-rays, photos and impressions of your teeth are done, the oral surgeon and orthodontist will formulate a treatment plan. 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 the pre-surgical phase! After surgery, braces will be resumed to fine tune the bite. It generally takes approximately 2 years to complete the whole treatment and retainers will have to be worn after to maintain stability of the bite. The treatment plan and total time required differs on a case by case basis.

How is orthognathic surgery done?

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

The incisions are made inside your mouth to avoid scars on your face. However, small external incisions may sometimes be required. The jaw bones are then cut, moved and placed into their planned positions. Titanium plates and screws are inserted to fix the jaw bones in their “ideal” positions.

The surgery could involve the upper jaw, lower jaw or chin, depending on the problem. 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 mobilised. 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 mobilised. Chin surgery or genioplasty is done by separating the chin from the lower jaw. These mobile segments are stabilised with mini plates and screws to allow bony healing.

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

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

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. Rarely, there may be facial palsy 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 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. In extremely rare occasions, the affected tooth/teeth may have to be extracted.

Pain at the jaw joint. 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.

Do the titanium plates and screws need to be removed?

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. They also are deeply buried and will not be felt through the skin. Some of you may wonder if the plates and screws will set off alarms at security checkpoint metal detectors. Since titanium is a non-ferrous metal with extremely low magnetic field, the metal detectors will not be set off, so you can travel in peace!

Is orthognathic surgery worth going through?

The improvements in bite, speech, appearance and quality of sleep outweigh the downsides of the surgery. At the end of the day, the decision to proceed with the surgery lies with you and what you want. It is best to have a frank discussion with your orthodontist, surgeon and even with people who have undergone this surgery before making up your mind.