Retrognathia: A Small or Recessed Lower Jaw and the Impacts on Health

Snoring and Sleep Apnea Commonly Result, Surgery May Be Curative

The lower jaw, or mandible, is illustrated in red and when small or recessed with retrognathia may contribute to snoring and sleep apnea
The lower jaw, or mandible, is illustrated in red and when small or recessed with retrognathia may contribute to snoring and sleep apnea. SCIEPRO/Science Photo Library/Getty Images

In what is a fairly common facial characteristic, a small or recessed lower jaw can contribute to conditions that affect eating as well as breathing during sleep. What is retrognathia? How does the position of the mandible especially contribute to snoring and sleep apnea? Learn about retrognathia and therapy options, including orthodontic treatment and surgery.

What Is Retrognathia?

First, it is important to understand just what it means to have retrognathia.

Retrognathia is defined as having a recessed jaw, most commonly the lower jaw called the mandible. It may also affect the upper jaw known as the maxilla. It does not necessarily mean that the jaw is abnormally small (although it may be), just that it is set back when the face is viewed in profile. People with a smaller jaw, a condition known as micrognathia, inevitably also have retrognathia. It is also possible to have a normal-sized mandible that is simply set back, however.

What Causes Retrognathia?

The anatomical structure of the face is based at least in part in genetics, so that people often look like others in their immediate family. There are rare genetic conditions that can cause severe retrognathia, including Pierre-Robin syndrome. It may also be associated with other genetic conditions such as Marfan syndrome. Many people with recessed jaws do not have any identified specific genetic abnormality.

There are other rare causes of retrognathia. It may result if trauma to the jaw occurs early in development. It may also result from surgery, especially with procedures to treat cancer affecting the jaw.

​The overall prevalence is not well studied. Due to variations in the degree of retrognathia that may be present, it is not precisely known how many people may have the condition.

Problems with Retrognathia Include Snoring and Sleep Apnea

In young children, retrognathia may impact the ability to adequately feed from either breast or bottle. As the affected person develops, misalignment of the teeth may impact the ability to bite or chew food adequately later in life. This is worsened if the upper and lower teeth do not meet in the front. If the lower jaw is smaller, the teeth may be crowded or irregularly positioned and may have difficulty coming in normally. Teeth extraction may impact the normal growth of the jaw.

There is also a lot of evidence that retrognathia may contribute to disrupted breathing, especially during sleep. This may lead to snoring or even sleep apnea. Sleep apnea occurs when the upper airway either partially or completely collapses during sleep. This occurs more in retrognathia due to the jaw shifting the tongue back into the airway. This will contribute to pauses in breathing, gasping or choking, and other symptoms such as daytime sleepiness.

Treatments of Retrognathia

Depending on the severity of retrognathia, treatment may or may not be necessary. If it is identified early in development, children and adolescents can go through orthodontic treatment that may be effective in reducing the degree of the condition. For example, a headgear may be used to slow the growth of the opposite jaw so that they can become better aligned. 

In late adolescence or adulthood, once growth is completed, it may be necessary to have surgical treatment to move the jaw forward. This is often called maxillomandibular advancement (MMA) surgery. Both jaws can be moved forward so that braces are not necessary to realign the teeth; instead they are kept in their original relationship. These surgical procedures are performed by oral surgeons and can cost up to $50,000 to $100,000, with costs often covered in part by insurance.

If sleep apnea is present, the same treatments can be effective as would be used in anyone else. These include continuous positive airway pressure (CPAP) and an oral appliance.

If you are concerned about the health impacts of your jaw positioning, speak with your dentist or doctor about some of the options that may be available to evaluate and treat your condition.

Sources:

Guilleminault C, Abad VC, Chiu H, Peters BR, and Quo S. “Missing teeth and pediatric obstructive sleep apnea.” Sleep and Breathing. 2015 Sep 2.

Joshi N et al. “Skeletal Malocclusion: A Developmental Disorder With a Life-Long Morbidity.” J Clin Med Res. 2014 Dec; 6(6):399-408.

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