An overbite is a common dental condition where the upper front teeth extend vertically over the lower front teeth. While a small degree of overlap is a normal and necessary part of a healthy bite, an overbite occurs when this overlap becomes excessive. This misalignment can affect both the appearance of a person’s smile and the proper functioning of their mouth.
What Exactly Is An Overbite?
An overbite is a type of malocclusion, meaning misaligned teeth or an improper bite. A normal bite involves the upper front teeth slightly overlapping the lower front teeth by about 1-2 millimeters. If the upper teeth overlap the lower teeth by more than 2 to 4 millimeters, it is classified as an overbite.
Overbites can present in different ways. A “deep bite” occurs when the upper front teeth excessively cover the lower front teeth, sometimes to the point where the lower teeth bite into the roof of the mouth or gum tissue behind the upper teeth. Another type, often confused with overbite, is “overjet” or “buck teeth,” which refers to a horizontal protrusion where the upper teeth stick out forward beyond the lower teeth. An individual can have both an overbite and an overjet simultaneously.
How Common Are Overbites?
Overbites are common in the general population. Globally, malocclusion is estimated to affect around 56% of the population, with no significant gender differences. In the United States, the average overbite measures 2.9 millimeters. Approximately 8% of the U.S. population aged 8 to 50 has a severe overbite of 6 millimeters or more.
Among children aged 6-11 years, 50.7% had overbite measurements within the normal range of 0-3 mm, while 37% had slightly excessive overbites of 4-5 mm. Severe overbites, measuring 6 mm or more, were observed in 7% of children in this age group. Among youths aged 12-17, severe overbites of 6 mm or more were more common in white youths (11.7%) compared to black youths (1.4%).
Why Do Overbites Occur?
Overbites can develop due to a combination of genetic factors, childhood habits, and developmental issues. Genetics play a role, as inherited jaw structure can predispose an individual to an overbite. A common genetic cause is when the lower jaw is smaller or underdeveloped compared to the upper jaw, leading to backward positioning of the lower teeth relative to the upper ones.
Childhood habits can also contribute to the development or worsening of an overbite. Prolonged thumb-sucking or pacifier use can exert pressure on developing teeth and jaws, causing them to grow at incorrect angles or shifting the upper teeth forward. Tongue thrusting, where the tongue pushes against the front teeth during swallowing, is another habit that can gradually move teeth forward and contribute to an overbite. Excessive nail biting or teeth grinding (bruxism) can contribute to misaligning teeth and exacerbating an overbite. In some cases, issues like missing teeth or abnormal tooth eruption can disrupt the natural balance of the bite, leading to overbite development.
When An Overbite Is A Concern
While a minor overbite is often harmless, an excessive overbite can lead to various functional and aesthetic concerns that require professional attention. One issue is compromised oral function, leading to difficulty biting or chewing certain foods efficiently. This can impact digestion and cause discomfort during meals. The abnormal bite alignment can also place undue strain on the jaw joints, leading to temporomandibular joint (TMJ) disorders, causing jaw pain, clicking, headaches, or even ear pain.
An overbite can also accelerate tooth wear and damage due to the constant, uneven friction between misaligned teeth. This can result in chipped, cracked, or worn-down teeth, making them more susceptible to cavities and sensitivity. An overbite can also affect speech clarity, as proper tooth alignment is involved in forming certain sounds, such as “f” and “s” sounds. Beyond functional issues, overbites can also cause aesthetic concerns, impacting a person’s smile and facial profile, such as creating a recessed chin appearance. Consult a dental professional, such as an orthodontist, for an assessment to determine if intervention is needed.