What Is an Underbite
An underbite, also known as Class III malocclusion, is a dental condition where the lower front teeth and jaw extend beyond the upper front teeth. Addressing an underbite can improve both oral function and facial symmetry.
Understanding What an Underbite Is
An underbite is characterized by the lower teeth and jaw protruding forward past the upper teeth. In a typical bite, the upper front teeth slightly overlap the lower front teeth when the mouth is closed. With an underbite, this relationship is reversed, meaning the lower jaw and teeth sit in front of the upper jaw and teeth. This condition can range from subtle to severe, where the teeth may not meet at all.
A prominent lower jaw or a “bulldog-like” appearance can indicate a more severe underbite. This misalignment differentiates an underbite from other bite issues, such as an overbite where the upper teeth extend too far over the lower teeth.
Common Causes of Underbites
Genetic predisposition is a primary factor. Individuals are more likely to have an underbite if family members also have the condition, as genes influence jaw and teeth size and shape. This inherited trait can manifest as an underdeveloped upper jaw, an overdeveloped lower jaw, or a combination.
Environmental factors can also play a role, particularly during childhood. Prolonged habits such as thumb-sucking, excessive pacifier use, or extended bottle-feeding can influence jaw growth. Tongue thrusting, where the tongue presses against the teeth during speech or swallowing, is another behavioral factor. Additionally, a severe injury to the face or jaw can result in misalignment.
Potential Health and Functional Impacts
An underbite can lead to various practical problems. Individuals may experience difficulty chewing food properly. The misalignment can also cause excessive wear on certain teeth due to improper contact, potentially leading to chipping, cracking, or increased risk of tooth decay and gum disease.
Speech impediments, such as a lisp, can also arise. Chronic jaw pain and temporomandibular joint (TMJ) disorders are common complications, resulting from uneven pressure on the jaw joint. This can manifest as headaches, earaches, facial pain, or a popping sensation in the jaw. An underbite may contribute to breathing problems, including snoring and sleep apnea, as jaw misalignment can obstruct airways during sleep.
Treatment Approaches for Underbites
Treatment options vary depending on the patient’s age and the severity. For children, whose bones are still growing, early orthodontic intervention is effective. Appliances like palatal expanders can widen a narrow upper jaw, while reverse-pull face masks or chin caps can guide upper jaw growth or restrict lower jaw growth. These methods use a child’s natural growth potential for better alignment.
For adolescents and adults, braces or clear aligners are common methods to correct tooth positioning. Braces, including metal, ceramic, or lingual types, gradually move teeth into proper alignment. Clear aligners are effective for milder cases.
In severe cases, particularly when the underbite is due to a significant skeletal discrepancy and jaw growth is complete, orthognathic surgery (jaw surgery) may be necessary. This procedure involves repositioning the jawbones to achieve proper alignment and improve function. A dental professional can diagnose and develop a personalized treatment plan.