What is orthognathic surgery?

 

Orthognathic surgery (Greek “orthos” means straight and “gnathos” means jaw) is a single or multiple jaw surgery which is performed to reposition the jaws. The main goals of the orthognathic surgery are to correct jaw alignment and occlusion, as well as, to achieve facial harmony. When the jaws are moved forwards or backwards, up or down, or rotated, the facial soft tissue in the chin, cheeks, lips and tip of the nose move accordingly, although there is a discrpancy in the amount of movement. One should aim to achieve both good occlusion and beautiful profile, whenever we start planning an orthognathic procedure.

 

Previously, both dental and skeletal malocclusions were managed with orthodontic treatment alone but, at the present day, a combined orthodontic and surgical treatment is available in all cases. The treatment begins with preoperative orthodontic setup and after the dental arches are aligned, jaw surgery is then performed so to fix one or both jaws in the new correct position. Orthodontic treatment continues for a long as necessary after surgery until all the teeth are brought into perfect occlusion. One or more splints are usually required, to guide the surgeon in achieving the desired stable occlusion.

Age limits

Orthognathic surgery is performed after the age of 18 years when the jaws normally stop growing, but it can be done also after the age of 16, in some selected cases. If orthodontic treatment is not effective by the age of 16, the patient and parents must give their consent before setup for orthognatic surgery is initiated, following a thorough documentation.

 

Malocclusion

Malocclusion may be classified into two major groups: skeletal and dental.

Skeletal malocclusion is caused by discrepancy in shape, size and/or position of one or both jaws; e.g., if one of the jaws is too large or too small, or if one of them is too large and the other one is too small. For these patients a simple alignment of dental arches provides little help since their teeth are not in proper occlusion since the jaws don’t match each other. Skeletal malocclusion is often accompanied by an unpleasant facial profile. The profile is too convex if the lower jaw is too small; or too concave if the lower jaw is too big, the upper jaw is too small, or both. Orthodontic treatment alone is insufficient for successfully correcting skeletal malocclusions when the chewing function and the facial aesthetics is also a desired outcome in addition to occlusion. Surgery, on one or both jaws, is usually performed to correct the position of the jaws, improve the chewing function, enhance the facial features, and reduce airway related problems. If the jaw interrelation is correct in a patient, the dental malocclusion may be the result of an incorrect inclination or crowding of the teeth and in these cases orthodontic treatment alone could be sufficient to achieve a stable correct occlusion.

 

Jaw size abnormalities

Distal bite

 

Occlusion. Distal bite is often the result of a small lower jaw which causes the lower teeth to fall behind the upper teeth. Occasionally, the front teeth may be obviously flared.

 

Facial profile. The facial profile is usually convex. The face may also be short which has a small chin with a deep fold between the chin and the lower lip.

 

Airway. Due to a smaller lower jaw the airway often becomes tapered which may cause the patient to snore and have sleep disorders.   

 

Chewing function. The chewing function is satisfactory.

 

Jaw joints.  Patients often try masking their distal bite by thrusting their lower jaw forward and therefore cause overstretching of the joint's ligaments which results in hypermobility of jaw's joints.

 

Teeth wear. Molars may be heavily worn out if cusp-to-cusp contact is the result of jaw mal-position.

Distal bite
case 1-distal bite, endooral aspect

Mesial bite

 

 

Occlusion. Lower front teeth are in edge-to-edge contact, or, in front of the upper front teeth. This may result in a large lower jaw, a small upper jaw, or both.

 

Facial profile. Facial profile is usually concave with a protruding chin and a receding mid-face.

 

Airway. Mesial bite is normally not associated with reduced airway difficulties.

 

Chewing function. The chewing function is normal or satisfactory if the front teeth come in contact.

 

Jaw joints. Due to the incorrect position of the lower jaw and the uneven occlusion, clicking or popping of the joints may be noticeable.

 

Teeth wear. The molars are worn more than the front teeth. Front teeth may be heavily worn if they are in edge-to-edge contact.

 

 

Mesial bite
case 1-mesial bite, endooral aspect
Mesial bite
case 2-mesial bite, endooral aspect
Mesial bite
case 3-mesial bite, endooral aspect
Mesial bite
case 4-mesial bite, endooral aspect
Mesial bite
case 5-mesial bite, endooral aspect
Case 1, Open bite
Case 1, Open bite
Case 1-open bite, endooral aspect
Case 2, Open bite
case 2-open bite, endooral aspect
Case 3, Open bite
case 3 open bite, endooral aspect
Case 4, open bite
case 4 -open bite, endooral aspect
Case 5, open bite
case 5-open bite, endooral aspect
Case 6, open bite
case 6-open bite, endooral aspect

Occlusal depth abnormalities

 

Open bite

 

Occlusion.The molars are the only teeth that come in contact. When the mouth is closed, no overlap or a gap between the upper and lower front teeth is noticeable. The incorrect position and shape of the upper jaw, or the divergent growth profile of both jaws, are frequent causes for this malocclusion. This type of malocclusion is often diagnosed for patients who are mouth-breathers or who had sucked their thumbs for an extended period of time.

 

Facial profile. The lower third of the facial profile is usually convex and long often causing the lips to be strained when attempting to keep the lips closed.

 

Airway. The airway may be tapered and the patient may suffer from snoring, especially if the patient has a small lower jaw.

 

Chewing function. The chewing function is unsatisfactory. Molars and sometimes premolars are the only teeth that participate in the chewing process. It is also difficult to bite off food since the front teeth do not come in contact.

 

Jaw joints. Jaw joints may be traumatized since the occlusion is not stable and the molars take over the entire chewing load.

 

Teeth wear. Molars are often severely worn since they are the only teeth that are utilized for chewing.

 

 

Deep bite, facial aspect
Deep bite, occlusal aspect

Deep bite

 

Occlusion. The overlap of the front teeth is too big, and on some occasions, the upper front teeth may completely cover the lower front teeth. A deep bite is often the result of a small lower jaw and incorrectly aligned teeth.

 

Facial profile. The facial profile is usually convex and the lower third of the face is short. The upper lip may be either normal or protruding, whereas, the lower lip is curled with a deep fold above the chin.

 

Airway. A deep bite is sometimes associated with a reduced airway especially if a patient has a small lower jaw.

 

Chewing function. The chewing function may be satisfactory or even normal. In patients who have a very deep bite, the lower teeth may traumatize the palatal mucosa and later cause a flaring of the upper front teeth.

 

Jaw joints. Jaw joints may suffer if a deep bite is accompanied by an uneven occlusion.

Teeth wear. Molars may wear down faster if the cusp-to-cusp contact is the result of the jaw's misplacement.

 

 

Case 1, cross bite
Case 2, cross bite
case 2- cross bite, endooral aspect
Case 3, cross bite
case 3-cross bite, endooral aspect

Width abnormalities

 

Cross bite

 

Occlusion. The upper molars are inclined or positioned inward more than the lower molars. Most often occlusion is caused by a narrow upper jaw or the incorrect position of the teeth within the dental arches. In many cases, a cross bite is associated with mouth breathing.

 

Facial profile: The cross bite alone has no significant influence on the facial profile; however, it is frequently associated with an open bite which results in a long and convex facial profile.

 

Airway: The airway may be tapered and the patient may have snoring problems. Cross bite is diagnosed in children and adults who frequently keep their mouth open because of impaired nasal breathing.

 

Chewing function: The chewing function is satisfactory.

 

Jaw joints: A cross bite often causes uneven occlusion and may also cause clicking or popping in the joints.

 

Teeth wear. Molar wear may be noticeable.

 

 

 

 

Scissor bite

 

Occlusion. The upper molars are positioned outward or the lower molars are positioned inward. When the mouth is closed the molars miss each other and overlap with no contact. A possible reason for this is a naturally narrow lower dental arch or a hyper-expansion of the upper jaw resulting from wearing orthodontic appliances in childhood.

 

Facial profile. The scissor bite has no significant influence on the facial profile.

 

Airway: The scissor bite is not known to reduce airway.

 

Chewing function: The chewing function is bad since the molars make no contact with each other.

 

Jaw joints: Patients may experience a clicking or pain in the jaw joints since the jaw is usually forced to function in a deviated position during the chewing process.

 

Teeth wear: Molar wear is unlikely since the molars do not come in contact with each other.

 

Jaw asymmetry

 

Vertical asymmetry

 

Face. The lower jaw angles are found at different heights so that the whole lower third of the face looks twisted. This is accompanied by a vertical cant in the lip line both in repose and during smiling, as well as, a cant in the teeth line.

 

Occlusion. Usually there is a cross bite on one side and a normal bite on the other side which tends toward the mesial bite. However, there may be a variety of different types of occlusion

 

Facial profile. The facial profile may vary. Most often a vertical asymmetry develops when the jaw growth is either retarded or accelerated on the one side; for example, this could be the result of a traumatic injury during growth.

 

Airway: Vertical asymmetry has no known significant influence on the airway.

 

Chewing function: The chewing function is satisfactory.

 

Jaw joints: Vertical asymmetry does not directly cause jaw joint difficulties.

 

Teeth wear: Molars may be worn down due to unfavorable contact between the teeth.

 

Horizontal asymmetry

 

Face. The lower jaw body is longer on one side; so therefore, the chin obviously moved toward the shorter side. Horizontal asymmetry usually develops when the growth of one side of the lower jaw is accelerated. The cause for this growth acceleration is unknown.

 

Occlusion. Usually there is a cross bite on one side of the jaw which has the tendency to develop into a mesial bite. The upper dental arch is often normal and may not be affected by the position and shape of the lower arch.

 

Facial profile. The facial profile is usually concave.

 

Airway. Horizontal asymmetry has no known influence on the airway size.

 

Chewing function. The chewing function is satisfactory.

 

Jaw joints. A significant case of horizontal asymmetry may cause clicking or popping in the jaw joints during the chewing function.

 

Teeth wear. Molars may wear down due to the severe mal-position of the jaws and uneven occlusion.

 

 

Jaw orientation abnormalities

 

Gummy smile

 

Gummy smile is an aesthetic consequence rather than a malocclusion. It can be noticed in patients with either ideal or incorrect occlusion, as well as, in patients with upper jaw vertical excess. When smiling, patients show a fair amount of gums in their upper front teeth which looks unattractive in most cases.

 

Occlusion. Occlusion may vary, but most often a gummy smile is associated with distal bite. It is often caused by the low vertical position of the upper jaw and the blocked growth of the lower jaw.

 

Facial profile. Usually the facial profile is convex and the lower third of the face is long. Lips are strained when in the closed position.

 

Airway. Patients may suffer from snoring problems, especially if the gummy smile is accompanied by a small lower jaw and distal bite.

 

Chewing function. The chewing function depends on the type of malocclusion.

 

Jaw joints. Jaw joint symptoms depend on the type of malocclusion.

 

Teeth wear. Teeth wear depends on the type of malocclusion.

 

High facial angle

 

High angle patients usually have an extremely convex facial profile and a steep occlusal plane. The downward growth of both jaws results in a small and receding chin, reduced airway, and sleep problems. The reduced airway and chewing function are the main reasons this type of patients should have orthognathic surgery.

 

Occlusion. On rare occasions high-angle patients may have a correct occlusion. The occlusion may vary, but most frequently, a high angle face is accompanied by a small lower jaw and a distal bite. The high angle face is determined by the vertical direction of growth or by the disturbed growth of the ascending rami of the lower jaw caused by a childhood trauma of the jaw joints, congenital abnormalities, or rheumatoid arthritis.

 

Facial profile. The facial profile is extremely convex with a small chin often with a "second chin" beneath the first.

 

Airway. The airway passage is often reduced and the patient may have a tendency to snore and have sleep apnea.

 

Chewing function. The chewing function depends on the type of malocclusion.

 

Jaw joints. Symptoms in the jaw joints depend on the type of malocclusion, congenital abnormalities and jaw joint disease.

 

Teeth wear. The teeth wear depends on the type of malocclusion.

 

 

SURGICAL TREATMENT

 

There are several surgical procedures especially designed to re-arrange the facial architecture, of which the most frequently used are:

 

  • Le Fort type osteotomy ( can, be, according to the level of section, I,II and III)

  • Mandibular sagittal split (Obwegeser-DalPont)

  • Genioplasty (repositioning of the chin)

  • Sagittal maxillary split (surgically assisted maxillary expansion)

  • Segmental maxillary osteotomy

 

PLANNING / STEPS / PROCEDURES / RECOVERY / COMPLICATIONS / FOLLOW-UP

 

The first step in any case is the consultation, which not only offers information to the both surgeon and patient, but represents also the first and only chance to make a first impression on each other. It is of extreme importance for the surgeon to gain the patient’s confidence, in order to complete the case successfully. In our team, the first contact with our patients is essential for further development of each case. One should always explain our patients the diagnosis, the need for treatment, the necessary investigations, and the choice of treatment and of course, the possible complications, evolution and follow-up. Each question asked by our patients must be given a truly professional and convincing answer. The time for a consultation can vary from 20 to 45 minutes, or even more, in the very complex cases.

 

Normally, all patients who are candidates to orthognathic surgery come for the first consultation with all the necessary investigations in order to establish a diagnosis: special X-Rays ( OPT, lateral cephalograms, CT scans, CBCT,etc), dental model casts, as they are required by the orthodontist as well. During this first consultation only general aspects in regard with the deformity and treatment options will be discussed with the patient. A number of photos will be taken. We do not encourage online or by phone consultations, as we consider that to be a sign of unsubstantiality. Nevertheless, in those cases of overseas patients, a first contact via internet will be possible.

 

The second consultation will be scheduled within two weeks from the first one. Within this time, we examine each case thoroughly, do the necessary measurements and build a treatment plan that is expected to meet the expectation of our patient. The patient will be explained, in details:

  • treatment plan,

  • approximated length of surgery

  • expected results,

  • possible complications,

  • recovery

  • follow-up

 

We perform all the orthognathic procedures under general anesthesia, in order to offer comfort to both surgeon and patient. Each procedure will be chosen to suit each particular case.  Therefore, in some cases, more than one procedure will be required. Usually, in order to achieve both main goals of any orthognathic surgery, function and beauty, we perform the so called BIMAX (bi maxillary approach), associated or not with a chin correction.

 

The length of an orthognathic procedure will vary from 1.5 hours up to 4 hours, depending on the complexity of the case and the number of required procedures. Sometimes a bone grafting is required, in which case the duration increases. It is essential that the patients have braces and arches, with anchorage naps to facilitate the intermaxillary fixation during the surgical procedure and for two weeks after that. One or more acrylic splints will be made, in order to secure the intermediate and final occlusion.

 

Following these procedures, our patients will experience swelling, bruising, moderate pain and a certain degree of dysphagia. In some cases, where mandibular split was performed, patients will present temporary numbness at the level of the lower lip and chin, caused by even a mild touch of the inferior alveolar nerve, which will remain attached to one of the fragments of the mandible. For the first week all our patients will be fed via a naso- gastric tube, in order to secure the healing of the intraoral wounds. The entire surgical procedure is carried via intraoral approach, so there will be no external scars. Normally, after 3-4 days, our patients are discharged and weekly appointments are given, for at least two months.  When the naso-gastric tube is removed, the patients will eat only liquids, using a straw.  After two weeks, the tight elastic intermaxillary fixation is replaced with a rarer and softer one. The orthodontic treatment is usually continued, until the correct occlusion is achieved.