What is retrognathia?
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 a person has a severe overbite.
Oftentimes, the difference in placement between the lower and upper jaw isn’t noticeable head on but is when the person is viewed from the side, in profile.
Retrognathia can be a difficult condition to manage. Physically, it can affect your ability to sleep or eat properly. Some with the condition have had their self-esteem or confidence affected since the condition is visually noticeable.
There are a few causes of retrognathia, and treatment usually includes braces and hardware or surgery. In mild cases, no treatment may be needed.
Picture of retrognathia
What causes retrognathia?
Some people are born with retrognathia, and others develop it later in life. If the case is mild, it might not be diagnosed until childhood or adolescence.
The most common causes of retrognathia are:
- Pierre-Robin syndrome. This condition affects both the jaw and the tongue, and it creates a blockage of the airways.
- Hemifacial macrosomia. 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 jaw, creating retrognathia.
- Facial trauma or fractures. If a child experiences physical trauma or fractures, it can cause their jaw to not develop properly.
What complications can retrognathia cause?
Those who have retrognathia often have difficulty with jaw misalignment. This can affect their ability to eat or sleep without restriction. They 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 a person with retrognathia gets 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. Someone with retrognathia might also develop temporomandibular joint disorder (TMJ). This condition causes pain and muscle spasms.
Lastly, some people with the condition have trouble breathing, especially when sleeping. Their tongue might restrict their airway, which can cause snoring or sleep apnea. Sleep apnea causes a person to stop breathing multiple times per night, often unaware that this is happening.
How is retrognathia treated?
Treatment depends on the severity of the retrognathia. Some people may not need surgery or any type of treatment.
When a baby is born with retrognathia, they will likely go through a physical evaluation that will 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 will likely receive X-rays so the doctor can further determine what the condition looks like. The baby may then have 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,” meaning that the baby can undergo surgery to correct the condition. If so, they may undergo surgery while still in the hospital.
The most common surgeries are the bilateral sagittal split ostomy (BBSO) and distraction osteogenesis.
The distraction osteogenesis surgery is often the preferred method, because the surgeon doesn’t have to use bone grafts or wire the jaw. It’s also considered safer, because there is usually less blood loss and a decreased risk of infection.
Distraction osteogenesis has special hardware that can be placed either inside the mouth or outside. Once the individual fully heals from the procedure, they will be able to eat and chew as they would have without the condition.
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 orthodontics. For instance, special headgear can make the upper jaw grow more slowly so that the upper and lower jaws are more equal.
Once the child stops growing, in adolescence or adulthood, that child can have a maxillomandibular advancement (MMA) procedure, which makes both jaws move forward.
Those whose retrognathia causes sleep apnea can be treated with a continuous positive airway pressure (CPAP) machine.
What’s the outlook for retrognathia?
Someone with retrognathia will likely be treated by a number of doctors and often at various stages of development.
While those with mild retrognathia may not require any treatment, those with more severe conditions may need orthodontic treatments and/or surgery. Distraction osteogenesis can lengthen the jaw up to 10 or 20 millimeters—sometimes more.
After surgery, the individual’s jaw may slightly revert back to its original position. For instance, BBSO and wire fixation have an average relapse of 2 millimeters. However, even with some amount of relapse, the surgery is able to largely fix the condition.
Anyone seeking treatment for retrognathia 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 each individual’s needs.