An overbite is a common type of dental misalignment that affects a significant portion of the population. This issue falls under the broader term malocclusion, which refers to an imperfect positioning of the teeth when the jaws are closed. Malocclusion is a widespread dental condition and one of the most frequently addressed oral health concerns. Correcting this misalignment is important for maintaining long-term oral health and function.
Defining the Vertical Overlap
An overbite, often referred to as a deep bite, is defined as an excessive vertical overlap of the upper front teeth over the lower front teeth. Orthodontists typically measure this overlap in millimeters or as a percentage of coverage. A healthy, normal overlap is generally considered to be between 2 to 4 millimeters, corresponding to approximately 20% to 40% of the lower incisor’s crown height being covered by the upper teeth. When the vertical overlap exceeds this range, it is classified as a deep bite. In severe cases, the lower front teeth can completely disappear behind the upper teeth, sometimes making contact with the gum tissue or the roof of the mouth, which is known as an impinging overbite.
What Factors Contribute to Overbites
The development of an overbite is frequently multifactorial, arising from a combination of different influences.
Skeletal Factors
One primary category involves skeletal factors, which are often genetic. An overbite can occur if there is a discrepancy in the size or growth pattern of the upper and lower jaws, such as a lower jaw that is too small or set back relative to the upper jaw.
Dental Factors
Dental factors also play a role, arising from the positioning of the teeth themselves rather than the jawbone structure. These factors include the misalignment or crowding of individual teeth, or the early loss of baby teeth which can cause permanent teeth to erupt in an improper position.
Habitual Factors
A third set of causes is related to habitual factors, particularly those developed during early childhood. Prolonged habits like thumb sucking, extended pacifier use, or tongue thrusting can place continuous pressure on the teeth and jaw structure, pushing the upper front teeth outward. Teeth grinding (bruxism) or excessive nail biting can also contribute to or worsen an existing deep bite over time.
Problems Caused by an Overbite
An excessive overbite can lead to several functional and health complications beyond cosmetic concerns. One common issue is uneven tooth wear, where the lower incisors constantly rub against the inner surfaces of the upper teeth or the gum tissue behind them. This abrasive contact causes enamel erosion, increasing the risk of sensitivity, decay, or gum tissue damage.
The misalignment of the bite also places excessive strain on the jaw joint and surrounding muscles. This uneven pressure can lead to temporomandibular joint (TMJ) disorders, resulting in symptoms like chronic jaw pain, headaches, and difficulty opening or closing the mouth fully.
A significant overbite can impair the ability to properly chew food, leading to inefficient digestion and discomfort. The positioning of the teeth can interfere with normal tongue function, sometimes causing speech impediments such as a lisp. The altered facial profile can also negatively affect a person’s self-esteem.
Options for Correction
Treatment for an overbite is highly individualized, depending primarily on the patient’s age and whether the issue is dental or skeletal in origin. Early intervention in children, while their jaws are still developing, often involves specialized appliances like functional appliances or headgear to guide jaw growth. This approach addresses skeletal discrepancies before they become severe.
For adolescents and adults, the most common interventions involve traditional braces or clear aligners. Braces are highly effective for correcting moderate to severe overbites by gradually moving the teeth into the correct vertical and horizontal alignment. Clear aligners are a popular, more discreet option for mild to moderate cases.
In cases of severe dental crowding, extraction of one or two teeth might be recommended to create the necessary space. For adults with severe skeletal overbites, non-surgical orthodontics may be insufficient. In these instances, orthognathic surgery, or jaw surgery, may be required in conjunction with braces to reposition the jaws for a stable and functional bite.