Orthognathic Surgery for Class 2 bite or Mandibular Retrognathia

What is Mandibular Retrognathia and how is it treated?

Retrognathia, from the Latin retro, "backward" and from the Greek, gnathos, jaw, is a dentofacial deformity in which both jaws are misaligned with each other causing an anteroposterior discrepancy between upper and lower jaw: the first lower molar is posterior (or more towards the back of the mouth) than the first upper molar, which makes it appear that a person has a severe overbite. Often, this difference in the location between the lower and upper jaw is not noticeable in front, but it is very noticeable in the patient's profile.

In dental terminology, mandibular retrognathia is also called class II. A skeletal Class II malocclusion may be the result of:

• A prognatic or overdeveloped upper jaw
• A retrognathic or underdeveloped jaw
• and / or the combination of both.

Depending on the causes of retrognathia, treatment may include orthodontic braces, conventional orthodontics and / or surgical intervention. It is essential to differentiate the dominant causal factor from skeletal Class II malocclusion, since the orthopedic / orthognathic surgical treatment plan varies accordingly. In mild cases, no treatment is needed.


In most cases, class II problems are inherited genetically, and may be due to insufficient growth of the lower jaw, excessive growth of the upper jaw or a combination of both. According to some studies, the main contributing factor for class II skeletal malocclusion is mandibular retrognathism, followed by maxillary prognathism and with a small percentage of cases that combine both factors.

A class II malocclusion may also be aggravated by environmental factors such as finger sucking, allergies, poor respiratory function, atypical swallowing, or chronic mouth breathing. There may also be other factors for retrognathia, such as a retracted chin that lacks forward projection; or it may be due to a purely dental problem.


When there is this abnormal relationship between the maxilla and the jaw, the disharmony between the two structures causes distinctive facial features on the patient's face: the face lacks forward projection in its lower third and the upper front teeth and the upper jaw project more forward than the lower teeth and jaw, so there is a convex profile appearance, with a retracted chin and lower lip.

In addition, mandibular retrognathia affects patients not only at aesthetic level: many of the patients who have this type of malformation suffer from Sleep Apnea, a pathology that conditions their quality of life very negatively.


Retrognathia can be a difficult condition to handle. Physically, it can affect the patient's masticatory and phonatory abilities, Whereas some people with the condition also see their self-esteem or level of confidence affected, since the condition is visually remarkable.

Someone with retrognathia may also develop temporomandibular joint disorder (TMJ), a condition that causes pain and muscle spasms.

Likewise, there are also long-term reasons: as a person with retrognathism ages, their teeth tend to misalign, crowd, or position themselves in unusual positions.

Finally, some people with this condition have trouble breathing, especially when they sleep, since their airways are narrower than normal, which can cause snoring, or even obstructive sleep apnea, a syndrome that affects a little more of 25% of the population, and causes a person to stop breathing several times a night, often without realizing that this is happening. This condition affects not only their night rest, but also their daily activity, as they feel often drowsy and fatigued. In extreme cases this condition can even lead to death.

The solution of mandibular retrognathia or class II, apart from returning the quality of life to patients solving functional problems such as chewing problems or more serious pathologies such as Sleep Apnea, restores the aesthetic balance between maxilla and jaw.


While people with mild retrognathia may not require any treatment, people with more severe cases may need orthodontic treatment and / or surgery.

In children, retrognathia can be treated with orthodontics. For example, a special harness can make the upper jaw grow more slowly so that the upper and lower jaws are more equal. However, despite the excellent results that can be obtained with current orthodontic methods, no orthodontist or dentist can grow a jaw, and functional devices do not change the skeletal pattern to a significant degree, which is why severe cases of retrognathism in adults and in certain adolescents with low growth potential are best treated surgically or by a combination of surgical and orthodontic methods.

Thus the treatments indicated for retrognathia are:

If the problem is purely dental, or the patient is happy with his appearance and only wishes to correct his occlusion, the solution is an orthodontic treatment.
• For those patients with a good occlusion, but a retracted chin, a genioplasty, or chin surgery is recommended.
When there is a skeletal problem or sleep apnea, the indicated treatment is an orthognathic surgery, which may, or may not, be accompanied by an orthodontic treatment depending on the case.

It is important to note that after an orthognathic surgery of mandibular advancement, the individual's jaw may return slightly to its original position. The average setback in the scientific literature is 2 millimeters. However, even with a certain relapse, surgery can greatly correct the condition.

Anyone seeking treatment for retrognathia should speak with a medical professional for more information. Each case is unique, so the orthodontist or maxillofacial surgeon must evaluate, diagnose and treat the condition according to the needs of each individual.


Orthognathic surgery is a complex treatment aimed at simultaneously treating the function and aesthetics in the patient, and should always be performed by a maxillofacial surgeon.

In this sense, the surgeon's experience and technique play a crucial role in obtaining harmonic results on the face, while eliminating the discomfort caused by the mandibular prognathism. At the Maxillofacial Institute we carry out more than 200 orthognathic surgeries a year, which makes us a world reference center in this specialty. In addition, Dr. Hernández Alfaro, Director of the Maxillofacial Institute, has designed and published different techniques that are adopted by surgeons around the world.

Our 3D planning system and the minimally invasive techniques used by our medical team, in combination with the postoperative care provided by our team of nurses, make having surgery at the Maxillofacial Institute a much less traumatic experience, while the probability of surgery success and patient satisfaction is significantly higher than in other centers.