An underbite occurs when the lower front teeth extend beyond the upper front teeth, often due to the lower jaw protruding further than the upper jaw. This dental misalignment is also referred to as a Class III malocclusion or prognathism. While some underbites may be subtle, others are more pronounced, significantly impacting a person’s facial profile.
What Exactly Is An Underbite?
Normally, the upper front teeth slightly overlap the lower front teeth when the mouth is closed. In an underbite, this relationship is reversed, with the bottom teeth jutting out. This condition can range from mild, where the teeth barely overlap, to severe, with a noticeable gap between the upper and lower teeth.
The two main categories of underbites are dental and skeletal. A dental underbite involves misaligned teeth, where only the lower teeth are angled forward, appearing in front of the upper teeth. In contrast, a skeletal underbite arises from a disproportion in the size or position of the jaw bones, such as an underdeveloped upper jaw or an overdeveloped lower jaw.
Factors Contributing to Underbites
Underbites frequently have a strong hereditary component, suggesting that genes play a substantial role in their development. This genetic predisposition can lead to disproportionate jaw sizes or improperly positioned teeth from birth.
Beyond genetics, certain environmental factors during childhood can influence jaw development. Prolonged habits such as thumb-sucking, extended pacifier use, or tongue thrusting can exert pressure on developing teeth and jaws, contributing to the formation of an underbite. Additionally, trauma or injuries to the face or jaw during childhood can alter jaw alignment, potentially leading to an underbite if the jaw does not heal correctly.
Some medical conditions and syndromes are also associated with underbite development. Conditions like Down syndrome, Acromegaly, and Crouzon syndrome can affect craniofacial growth, leading to an increased risk of malocclusions, including underbites.
How Underbites Affect Daily Life
An underbite can lead to various functional challenges that impact everyday activities. Individuals may experience difficulty with chewing and biting food effectively, which can sometimes lead to digestive issues due to inadequate food breakdown. Speech can also be affected, with some people developing a lisp or other pronunciation difficulties because of the altered tooth and jaw positioning.
Beyond functional aspects, the appearance of an underbite can be a concern for many individuals. The protruding lower jaw can alter facial aesthetics, potentially affecting self-esteem and confidence. While mild cases may be less noticeable, more severe underbites can create a distinct facial profile that some individuals find unsettling.
Underbites also pose several oral health risks. The misalignment can cause increased wear on teeth, particularly the front teeth, as they may grind against each other abnormally. This can lead to enamel loss, tooth sensitivity, and even tooth fracture over time. Underbites can also contribute to jaw pain and temporomandibular joint (TMJ) disorders due to strain on the jaw muscles and joints, sometimes resulting in chronic pain or headaches. The misaligned teeth can also create hard-to-reach areas, increasing the risk of plaque buildup, tooth decay, and gum disease.
Pathways to Correction
Diagnosing an underbite involves a thorough clinical examination by a dentist or orthodontist, along with diagnostic records. These records often include dental X-rays to assess the underlying bone structure and tooth positioning, as well as impressions of the teeth to create models for detailed analysis. This comprehensive evaluation helps determine the type and severity of the underbite, guiding the selection of appropriate treatment.
Treatment approaches for underbites vary depending on the patient’s age and the severity of the condition. For children, early intervention is often recommended to guide jaw development while the bones are still growing. This may involve growth modification appliances such as reverse-pull headgear or chin caps, which encourage the upper jaw to grow forward or restrict the growth of the lower jaw. These appliances aim to correct the jaw discrepancy before it becomes more pronounced.
For adolescents and adults, orthodontic treatment with braces or clear aligners can correct dental underbites by repositioning the teeth. This approach is effective for misalignments primarily involving the teeth rather than significant jaw discrepancies. In cases of severe skeletal underbites where the jaw bones are significantly mispositioned, orthognathic surgery, also known as jaw surgery, may be necessary. This surgical procedure repositions the jaws to achieve proper alignment, often performed in conjunction with orthodontic treatment to align the teeth with the newly positioned jaws.