An overbite, or deep bite, is a common form of dental misalignment where the upper front teeth vertically overlap the lower front teeth when the mouth is closed. A slight overlap, typically between two and four millimeters, is actually a normal and necessary condition for healthy chewing function. Problems arise when this overlap becomes excessive, a condition orthodontists classify as a malocclusion that may require professional intervention to prevent oral health issues. The question of whether an overbite is “bad” depends entirely on the degree of this vertical overlap and the resulting functional problems it creates.
Defining the Overbite and Its Types
Clinically, an excessive vertical overlap is known as a deep bite, which occurs when the upper teeth cover the lower teeth by more than a normal amount, sometimes nearly hiding them completely. This misalignment can be caused by genetic factors determining jaw size and shape, or by prolonged childhood habits like thumb-sucking or extended pacifier use, which affect tooth and jaw development.
It is important to distinguish this condition from an overjet, which is a horizontal misalignment. An overjet measures how far the upper front teeth protrude forward past the lower teeth, often resulting in what is commonly called “buck teeth.” While an overbite is a vertical issue, and an overjet is a horizontal issue, many people experience both conditions simultaneously. Overbites themselves are classified as either dental, involving only the position of the teeth, or skeletal, involving a discrepancy in the size or position of the upper and lower jaws.
Functional and Health Implications
When the vertical overlap is excessive, an overbite stops being a cosmetic concern and begins to impact oral function and long-term health. Excessive tooth wear is a primary mechanical issue, where the lower front teeth repeatedly strike the back surfaces of the upper teeth or the gum tissue. This constant friction can accelerate the erosion of tooth enamel and lead to chipping or fracturing of the teeth, compromising their structural integrity.
A deep bite can also place mechanical strain on the temporomandibular joints (TMJ), which connect the jawbone to the skull. The misalignment forces the jaw muscles and joints to function in an unnatural position, which can lead to discomfort, chronic jaw pain, headaches, and a restricted range of motion. Severe cases can result in the lower teeth biting directly into the gum tissue on the roof of the mouth, causing chronic irritation and trauma to the palate.
An improperly aligned bite can impair the ability to efficiently bite and shear food, potentially leading to inefficient digestion. Speech impediments, such as difficulty pronouncing sibilant sounds, can also occur because the misaligned teeth interfere with the tongue’s precise movements required for certain sounds.
Determining When Correction is Necessary
The clinical decision to correct an overbite is based on the degree of overlap and the presence of functional impairment, rather than appearance alone. Orthodontists use specific measurements, typically in millimeters, to classify the severity of the malocclusion. An overlap greater than four millimeters is often considered excessive, prompting a recommendation for correction.
Mild overbites, generally in the four to six millimeter range, may only require intervention if they begin to cause functional problems. Moderate to severe overbites (six to eight millimeters or more) frequently require treatment to prevent the health risks discussed. In children, early intervention is often recommended to utilize the remaining jaw growth for simpler correction, guiding the bones into a more favorable position before development is complete.
Options for Correcting an Overbite
For cases where the misalignment is primarily dental, traditional metal or ceramic braces are highly effective, using brackets and wires to apply continuous force and reposition the teeth. Clear aligner systems, such as Invisalign, can also be utilized for mild to moderate overbites, often in conjunction with elastic bands that help move the teeth and jaw into the correct relationship.
In growing patients, specialized functional appliances, such as the Herbst or Twin Block devices, are often used to address skeletal issues. These appliances work by harnessing the body’s natural muscle activity and growth to reposition the lower jaw forward, correcting the discrepancy between the upper and lower arches. For the most severe skeletal overbites in adults, orthognathic surgery may be recommended to physically realign and reposition the jawbones.