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What Is Micrognathia?

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Medically Reviewed By Colgate Global Scientific Communications

Micrognathia is a condition where the lower jaw is undersized. It's quite common in infants, and in many situations, it corrects itself. This condition isn't preventable and may occur when a child has another syndrome. Understanding what causes an undersized jaw and how the condition affects an individual can help you accommodate any special needs and additional care they might need.

Causes of Micrognathia

Micrognathia is relatively common in infants. According to The Fetal Medicine Foundation, 1 case occurs in every 1,500 births. While this may sound concerning, it can be identified by an ultrasound during pregnancy, allowing the child to be born in a care facility that meets the family's needs.

Micrognathia causes can be hereditary or caused by a genetic mutation. It appears as a congenital disability that occurs with many syndromes, including Pierre Robin sequence, Stickler syndrome, Beckwith-Wiedemann syndrome, Treacher Collins syndrome, hemifacial microsomia, and cleft lip and cleft palate.

Symptoms of Micrognathia

The undersized jaw can cause issues with sleeping, nursing and breathing, especially when associated with Pierre Robin sequence, according to Children’s Wisconsin. Micrognathia can lead to improper position of the tongue, making it difficult for the infant to suck. In these situations, a feeding tube may help the child receive nourishment. The abnormal placement of the tongue may also affect the infant's ability to breathe normally. According to MedlinePlus, micrognathia can also cause irregular tooth alignment because of the limited amount of room in the mouth.

Doctors can sometimes diagnose micrognathia during an ultrasound before birth and follow the jaw’s growth throughout the pregnancy. But more commonly, craniofacial specialists will diagnose this condition after birth. They’ll perform a medical exam to determine if other facial conditions are present, like cleft palate. From there, they may order diagnostic imaging tests or conduct a sleep study for a more thorough examination.

Treatment Options

As a child develops, this condition often corrects itself, though micrognathia in adults can be observed if a medical professional does not treat it early. If this condition is present at birth, the jaw size corrects itself through growth between 6 and 18 months. However, if the condition does not correct itself, young patients are often instructed to wait until their adult teeth come in to see if they need treatment since the jaw will grow during puberty.

However, should the condition not resolve, medical professionals can use surgical and nonsurgical methods for treating this condition, with nonsurgical procedures being more common.

Nonsurgical methods do not change the jaw position, but they may allow for a more comfortable life. One treatment option is to change your child's sleeping position to lie face down, which encourages a clear airway. Some patients may also use a nasopharyngeal airway, a tube placed in the nasal passage to open the airway.

You should discuss surgery options extensively with your doctor, as their recommendations will differ based on your child's age and stage of development. These options may include a procedure to tie the base of the tongue to the lower jaw closer to the chin or a tracheostomy procedure to create an airway opening. To surgically lengthen the jawbone, your doctor may suggest an approach called mandibular distraction osteogenesis. This surgical treatment entails inserting screws into the jawbone during the first weeks of life. According to the Children’s Hospital of Orange County, the device may stay in place for 12 weeks until the new bone forms.

Additional Care

With micrognathia, early diagnosis is the key to managing the condition. Your medical professionals can provide advice on how to provide the best quality of life for the affected individual. When caring for someone with this condition or any of these syndromes, patience and commitment are essential.

Make sure to find a medical team that understands your child’s needs, including a dental professional who can accommodate your child's condition and guide them on a proper oral care routine. See them regularly for checkups to ensure your child's mouth is developing correctly and staying as healthy as possible.

Oral Care Center articles are reviewed by an oral health medical professional. This information is for educational purposes only. This content is not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your dentist, physician or other qualified healthcare provider. 

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