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Dr. Gerald Regni Jr & Associates

Underbite vs Underjet: What Is the Difference?

By Gerald Regni, DMD on June 04, 2018

Family portrait of three generations of womenThe way your teeth fit together plays an important role in your overall oral health. If they are out of alignment, it can lead to more serious issues, such as tooth erosion, chipping, TMJ disorder, and more.

There are several types of malocclusion, or orthodontic bite problems. Today, our team at Gerald Regni, DMD & Associates in Philadelphia, PA discusses underbite vs. underjet, and explores treatments in cosmetic dentistry to address these conditions.

What Is an Underbite?

Typically, the upper teeth should sit just outside of the lower teeth when in a closed position. An underbite is present when the lower jaw protrudes beyond the upper teeth. As a result, the lower teeth sit outside of the upper incisors.

This condition is not as common as overbite. In fact, only about five to 10 percent of the population has an underbite.

What Causes Underbite?

Underbites can range from mild to severe. In most cases, the condition is due to genetics, such as overcrowding or an overdeveloped lower jaw.

However, in some instances, underbites can be caused by early childhood habits. For example, mouth breathing, tongue thrusting, thumb sucking, or prolonged bottle or pacifier use can all cause an underbite to develop over time.

Treatments for Underbite

No matter what the cause, it is important to correct an underbite as soon as possible to prevent further issues from developing. An underbite can be corrected through non-surgical or surgical means, depending on the specific situation.

Some common treatments for children include:

  • An upper jaw expander
  • A reverse-pull face mask
  • A chin cap to restrict the growth of the lower jaw
  • Orthodontic braces to move the teeth into their desired positions

To address underbites in adult patients, more invasive treatment is often necessary. This is because bone growth and development are already complete. Treatments could include corrective jaw surgery, tooth extractions, and orthodontic braces.

What Is an Underjet?

Also referred to as “reverse overjet”, an underjet is characterized by protruding lower teeth. As a result, the lower teeth are positioned outside of the upper teeth when in a closed position. This can give the appearance of a prominent chin.

What Causes Underjet?

There are a few reasons why an underjet may be present. Some of the most common causes include:

  • Skeletal abnormalities: Any number of skeletal irregularities, such as a long lower jaw, can contribute to the development of an underjet.
  • Occlusion: If one or more teeth meet prematurely, it could lead to the displacement of the mandible over time, resulting in an underjet.
  • Growth patterns: An underdeveloped upper jaw or an overdeveloped lower jaw can lead to an underjet.
  • Restraint of growth: Cases in which a cleft lip or palate require repair could result in restraint of upper jaw growth. As a result, the lower jaw may appear larger and the lower teeth may protrude.

Treatments for Underjet

The treatment recommended for an underjet really depends on the complexity of the case. Some patients may benefit from Invisalign®. Others may require more traditional orthodontics treatment.

No matter what your situation, Dr. Regni can help you determine a treatment plan most appropriate for your unique needs.

Contact Our Practice to Learn More

If you have an underbite, underjet, overbite, or any other type of malocclusion, schedule a visit at our practice to explore your treatment options. You can call us at (215) 351-9399 or contact us online anytime.

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