What is Orthognathic Surgery?

Orthognathic surgery, more commonly known as jaw surgery, is done to fix the maxilla (upper jaw) or the mandible (lower jaw) when they are not lining up. Orthognathic surgery is not a one time event. It is actually a process that begins with orthodontia, followed by jaw surgery, and many months of recovery.

How Jaw Bone Problems Develop

Jaw bone problems can be congenital (present at birth) or develop later in puberty or  through injuries or other medical conditions that affect the jaw.

Congenital Jaw Problems

Treacher Collins syndrome and hemifacial microsomia are some classic examples of congenital jaw problems. Other common congenital jaw problems include:

  • Pierre Robin sequence. Children with the Pierre Robin sequence are born with small lower jaws. This makes it difficult for them to breathe or eat.
  • Craniofacial synostosis syndromes such as Crouzon Syndrome and Apert Syndrome where there are premature fusion of the cranial sutures
  • Facial clefts as described by Paul Tessier whereby the facial bones fail to fuse when they should have
  • Cleft lip and palate. This condition develops when the upper jaw and lip don’t develop normally, leaving a gap between the left and right side.

Developmental Jaw Problems

  • Open bite. People with an open bite have teeth that don’t come together when they close their mouth.
  • People with a underbite have some of the bottom teeth sitting out in front of their upper teeth.
  • This is when the upper front teeth is excessively in front of the lower front teeth.
  • Jaw asymmetry. This is due to excessive growth of the left or right side of the jaws relative to the opposing side, resulting in a crooked face which is slanted to one side.

Jaw Problems Caused by Medical Conditions and Injuries

  • Growth disturbances. This refers to the changes in the jaw when the body produces too much growth hormone due to a benign tumour in the pituitary gland. The excess hormone can make the lower and upper jaw grow excessively large.
  • Facial fractures. The lower jaw can break when hit by an object or punched. The upper jaw can break when you get hit, fall, or get involved in a motor vehicle accident. Such fractures if not properly treated may heal in a wrong position necessitating corrective surgery.
  • Temporomandibular joint (TMJ) disorders. This condition occurs when the jaw joints are misaligned.
  • Obstructive sleep apnea (OSA). This condition develops when the tonsils, airway muscles, tongue, or excess tissue blocks the airway so breathing stops and starts while you sleep. The underlying cause may be due to jaw sizes being too small to accommodate the oral tissues such as the tongue, tonsils etc.
  • Tumors and cysts. Slow growing benign tumours in the jaw may disturb the normal development of the jaw that does not regress even after the tumour has been remvoed

The Different Types of Orthognathic Surgery

When the jaw sticks out too little or too much, the facial feature can become unbalanced. Jaw surgery can correct this type of problem. There are three different types of jaw surgery:

  • Double-jaw surgery. This surgery is done to address problems that affect both the upper and lower jaw.
  • Maxillary osteotomy. This procedure is done when the upper jaw is the sole cause of the facial disharmony.
  • Mandibular osteotomy. This procedure is done when the lower jaw is the sole cause of the facial disharmony.
  • Facial bone contouring surgery. This is usually done on the overgrown parts of the jaws that are non tooth-bearing eg the lower border and angle of the lower jaw, the cheek bone.
  • Facial bone implants. Implants are inserted into the edges of the facial bones that are lacking in contour to achieve a more defined jaw line.

Possible Complications or Risks

Since it’s a surgical procedure, jaw surgery can come with risks and complications. Some of the most common complications and risks associated with jaw surgery can include:

  • Damage to the teeth
  • The bones not healing as they should
  • The original bite problem can return
  • Problems with the jaw joint
  • Needing additional surgery to address issues that the first procedure did not solve
  • Inability to open the mouth as wide as you would like
  • The lower lip and the cheeks remain numb after the procedure

What to Expect During the Recovery Period

Recovery can vary from one patient to another. However, most can recover at home and return to school or work after. Light exercises like short walks can be done during recovery. It is recommended that you check with your healthcare provider if you wish to add any exercise to your routine.

It can take a year for the jaw to completely heal. Typically, you will be asked to visit your healthcare provider weekly after the procedure for the first month or so. During your visit, your surgeon will remove the stitches and check the healing of the wound and stability of the jaw position.