Retrognathia (formally known as mandibular retrognathia) is a condition in which the lower jaw is set further back than the upper jaw, making it look like you have a severe overbite.
Oftentimes, the difference in placement between the lower and upper jaw is only noticeable when you’re viewed from the side.
Retrognathia can be a difficult condition to manage. Physically, it can affect your ability to sleep or eat properly. You may find that the conditions affects your self-esteem or confidence, since the condition is visually noticeable.
There are a few causes of retrognathia. Treatment usually includes orthodontic appliances, braces and hardware, or surgery. In mild cases, no treatment may be needed.
Some people are born with retrognathia, and others develop it later in life as their jaws grow. If the case is mild, it might not be diagnosed until your childhood or adolescence.
The most common causes of retrognathia are the following:
- Pierre-Robin syndrome. This condition affects both the jaw and the tongue, and it creates a blockage of the airways.
- Hemifacial microsomia. With this condition, one side of the lower face doesn’t grow fully and is underdeveloped.
- Nager syndrome. This rare condition affects both the jaw and the cheeks as well as the development of the hands and arms.
- Treacher Collins syndrome. This condition affects various bones in the face, including the jaw.
- Surgery to remove a tumor. Removing a tumor in the mouth can alter the lower jaw, creating retrognathia.
- Facial trauma or fractures. If a child experiences physical trauma or fractures, it can cause their jaw to not develop properly.
If you have retrognathia, you likely often have difficulty with jaw misalignment. This can affect your ability to eat or sleep without restriction. You might also experience intense jaw pain.
Babies with retrognathia may have trouble using a bottle or nursing because they can’t latch onto a nipple. As they get older, their teeth might become misaligned. The teeth can also get crowded together or positioned in an unusual way.
This irregular positioning of the teeth can make it hard to bite and chew food. You might also develop temporomandibular joint disorder (TMJ). This condition causes pain and muscle spasms.
Lastly, you may have trouble breathing, especially when sleeping. Since your lower jaw is retruded (placed farther back), your tongue might restrict your airway, which can cause snoring or sleep apnea. Sleep apnea causes you to stop breathing multiple times per night, often without knowing it.
Treatment depends on the severity of the retrognathia. You may not need surgery or any type of treatment.
When a baby is born with retrognathia, they’ll likely go through a physical evaluation that’ll help the doctor determine how best to treat the condition.
First, the baby’s ability to breathe will probably be monitored in the newborn/infant intensive care unit (N/IICU).
They’ll likely receive X-rays so that the doctor can further determine what the condition looks like. The baby may then undergo a sleep study.
If the baby is diagnosed with obstructive sleep apnea, the plastic surgery and pulmonary departments will probably see if the baby meets the criteria for a “favorable jaw.” If the criteria are met, the baby can undergo surgery to correct the condition, perhaps while still in the hospital.
The most common surgeries are the bilateral sagittal split ostomy (BSSO) and distraction osteogenesis.
During the BSSO, the lower jaw is carefully cut on both sides and moved forward to an ideal position. It’s held in place with metal plates.
For the distraction osteogenesis surgery, a special hardware is placed inside the jawbone with an extension placed either inside the mouth or outside. The device is activated to stimulate new bone formation.
Once the baby fully heals from the procedure, they’re usually able to eat and chew as they would’ve without retrognathia.
The distraction osteogenesis surgery may be the preferred surgery because there’s less blood loss and decreased nerve injury.
In children and adolescents
When retrognathia isn’t severe, it may not be noticed until early childhood. When this is the case, the child can often be treated with dentofacial orthopedics or orthodontics to modify growth and improve teeth alignment.
Dentofacial orthopedics uses biomechanical treatment, like orthodontic appliances, to change the relationship of the jaws and muscle activity to affect the growth of the face.
For instance, special headgear can make the upper jaw grow more slowly so that the upper and lower jaws are more equal. Functional appliances can also promote mandibular growth by placing the lower jaw in a forward position.
These types of appliances used to advance the mandible forward have also been shown to help with sleep apnea.
Epigenetic orthopedics is an emerging area that looks at the role of genes regulating jaw and face development and uses treatment at critical growth times to turn genes on and off. Treatment typically involves dental appliances that are worn to help reposition the jaws to modify growth.
In adolescence or adulthood, the person may still need to have a maxillomandibular advancement (MMA) surgery if they’re still retrognathic once they stop growing.
During the MMA procedure, both the upper and lower jaws are advanced (the lower jaw with a BSSO). Patients will most likely need to have orthodontics to align their teeth before this surgery.
In addition to the treatments above, those whose retrognathia contributes to sleep apnea may need to use a continuous positive airway pressure (CPAP) machine to help them sleep. CPAP doesn’t cure sleep apnea, but it improves breathing at night.
If you have retrognathia, you’ll likely be treated by a number of doctors, often at various stages of development.
While you may not require any treatment if your condition is mild, you may need dental orthopedic and orthodontic treatments as well as surgery if your condition is severe.
Surgery like distraction osteogenesis can grow more bone in the lower jaw and improve airway obstruction in infants born with retrognathia.
After surgery, the jaw may slightly revert back to its original position. But even with some amount of relapse, the procedure is able to largely improve the condition.
Adolescents or adults with retrognathia can benefit from surgery too, like MMA, which can improve their appearance and treat sleep apnea if they have it. Orthopedic appliances also can lengthen the lower jaw.
If you’re seeking treatment for retrognathia, you should speak with a medical professional to get more information. Since every case is unique, the doctor can evaluate, diagnose, and treat the condition according to your needs.