Orthognathic surgery

Orthognathic surgery

The face plays an important role on the aesthetic and functional level. It is the main element of appearance and is responsible for important functions maintaining good health. Indeed, eating, breathing, tasting, talking and feeling are all functions provided by the different components of the face.

The upper jaw (maxillary) and the lower jaw (mandible) occupy about two-thirds of the face. These support the teeth and together allow an effective masticatory function. In addition, the maxillary and mandible provide adequate support for the soft tissues of the face thus playing an important aesthetic role. Indeed, a non-harmonious relationship between these two bones and the teeth (malocclusion) could have unpleasant consequences for chewing, breathing and aesthetics.

Importance of orthognathic surgery

Malocclusion impairs the masticatory function, which has implications for chewing food. When the contacts between the upper and lower teeth are unsatisfactory, the grinding and incising of the food are not satisfactory either. In addition, dental overlap increases the difficulty of maintaining proper hygiene, increasing cariogenic risk and the risk of periodontal disease.

Severe skeletal malocclusions result in significant disproportion between the maxillary and mandible, which can affect the quality of life of the individual. Indeed, a mandible too small (mandibular micrognathia) can result in sleep disorders such as snoring and sleep apnea. In cases where the upper lip is too short and the vertical dimension of the maxillary is exaggerated, it becomes difficult for the individual to successfully close his lips together, which can lead to oral breathing that will aggravate the situation. In addition, temporomandibular joint pain can result from poor occlusion. An unfavorable relationship between the maxillary and the mandible causes exaggerated efforts of the masticatory muscles to improve masticatory function. This excessive muscle solicitation brings negative repercussions on the joint.

Finally, a disproportion between the jaws damages the aesthetics of the face. As mentioned at the beginning, the maxillary and mandible occupy 2/3 of the face and therefore, irregularities at this level will be very obvious. In profile, a convex face (bird facies) or concave is considered non-aesthetic and can have consequences in the social life of the individual.

Types of surgery

The three main approaches for orthognathic surgery are:

  • Bilateral Mandibular Sagittal Osteotomy (OSMB)
  • genioplasty
  • Lefort I Osteotomy

Bilateral Mandibular Sagittal Osteotomy (OSMB)

During this surgery, the mandible is cut behind the teeth to move it forward or backward.

Mandibular advancement

The mandible is sectioned in a sagittal plane on both sides behind the last tooth which allows the two pieces to slide over each other to allow positioning of the mandible at the desired location.

Then the two pieces on each side are screwed together with or without a plate.

Mandibular recoil

As for mandibular advancement, the mandible is sectioned in a sagittal plane on both sides behind the last tooth to allow positioning of the mandible at the desired location. A small bone fragment is removed to allow the mandible to move back.

Then the two pieces on each side are screwed together with or without a plate.

Whether for advancement or mandibular recoil, a small incision of a few millimeters on the skin of the cheek is often necessary to correcly perform the holes that receive the screws and facilitate the insertion of the latter. It is important to note that these screws are made of titanium (a biocompatible material) and will not trigger metal detectors at airports. The gingiva is finally sutured using resorbable stitches. This surgery can be done alone or in conjunction with another orthognathic surgery.

Genioplasty

This procedure involves moving the chin forward or backward. The choice depends mainly on being able to leave the lips relaxed together and the impact of the appearance.

Moving forward

The incision is made at the level of the hollowest region of the lower lip which reveals the chin bone. The latter is then sectioned to allow its repositioning to a more advanced level.

The chin is held in position with the help of wires or plates. The mucosa is then sutured using resorbable material.

Moving backwards

The incision is made at the level of the hollowest region of the lower lip which reveals the chin bone. The latter is then divided into two convergent planes towards the same point at the level of the upper part of the chin. The resulting triangular fragment is then removed to allow proper repositioning of the chin.

The chin is held in position with the help of wires or plates. The mucosa is then sutured using resorbable material.

Lefort I Osteotomy

This procedure involves the maxillary and moving it into different positions. It involves the treatment of:

  • Long face
  • Short face
  • Anterior open bite
  • Horizontal protrusion of the maxillary
  • Horizontal deficiency of the maxillary

Before orthognathic surgery

The vast majority of patients are referred to our clinic by orthodontists. These refer to complex cases where orthognathic surgery, in addition to orthodontic treatment, can give superior results compared to orthodontic treatment alone. However, it happens that some patients come to our clinic without having been referred by an orthodontist. In such a situation, where orthognathic surgery is considered, patients are referred to an orthodontist in the region since surgery is very rarely done without orthodontic appliances.

Sequence of treatment

Dental alignment using orthodontic appliance

The orthodontist will align the teeth without worrying about the intercuspation of the upper teeth with the lower teeth. The wisdom teeth must often be extracted during this process. The duration of orthodontic treatment is approximately 12 to 24 months and following this, the orthodontist will inform the surgeon when the patient is ready for orthognathic surgery. Another meeting with the maxillofacial surgeon is necessary to review the surgical procedure with the patient. Surgical planning is usually done 1 to 2 weeks prior to surgery using x-rays, photos, dental impressions and measurements.

Orthognathic surgery

With hospital surgery, the maxillary and/or mandible are realigned. For example, the mandible is advanced in a patient in skeletal class II. This may require spending a night or two at the hospital followed by a 2-4 week home recovery period.

Post-surgical orthodontics

Usually, it starts 4 to 6 weeks after the surgery. The orthodontist will adjust your teeth for a period of 6 to 12 months to optimize dental occlusion.

As you can see, many steps are necessary before reaching the final result. The duration of all this can vary between 1 to 3 years or more depending on the complexity of the case. The pins installed by the orthodontist must be worn throughout the treatment to ensure optimal results. In addition, exemplary hygiene must be maintained throughout the treatment.

The day of surgery

Usually, the surgery starts in the morning and is done under general anesthesia. There are several possible side effects related to the latter, namely:

  • Weakness
  • Dizziness
  • Nausea
  • Depression (a few weeks)
  • Nausea is extremely rare and can be prevented with the help of medications given before and after surgery. General anesthesia is administered by naso-tracheal intubation, ie a tube passes through the nose to reach the lungs. A slight sore throat due to intubation can be felt for 1 to 2 days following surgery.

After orthognathic surgery

When you wake up, you will have rubber bands between your top and bottom braces to guide the closing of your mouth. Since you are going to have difficulty opening your mouth fully during the first few days, it is suggested that you adopt a soft or liquid diet during this time. Despite this, you will be able to breathe well and talk. Postoperative pain is usually well controlled by the use of analgesic liquid form taken orally or intravenously.

The elastics will be in place for about two weeks and a healing period of about 6 to 8 weeks is necessary before you can chew normally and return to your usual diet.

After your operation, it is important to drink plenty of clear fluid. An adequate amount of fluid is needed to stop the effects of the injected products during general anesthesia.

Impeccable dental hygiene is very important (brushing 4 to 6 times a day) following orthognathic surgery. Brushing should be done directly on the teeth. In addition to brushing, a mouthwash, usually based on Chlorhexidine (Savacol), should be used.