An overbite, technically known as a deep bite or a Class II malocclusion, occurs when the upper front teeth significantly overlap the lower front teeth when the mouth is closed. A small amount of vertical overlap is expected and beneficial for normal chewing function. Whether a person can live comfortably with an overbite depends entirely on the degree of this overlap and whether it causes symptoms. A mild overbite is a common, stable finding that usually does not require intervention. When the overlap becomes excessive, it can cause progressive damage to the teeth and jaw structure.
Understanding the Types and Severity
The term “overbite” describes a spectrum of conditions, making severity the most important factor in determining potential health consequences. In a typical, healthy bite, the upper front teeth cover approximately 25% to 40% of the lower front teeth, corresponding to a vertical overlap of about 2 to 4 millimeters. This measurement is considered the normal range and poses no functional issues.
An overbite becomes classified as excessive, or a deep bite, when the upper teeth cover more than 40% of the lower teeth, often exceeding 4 to 6 millimeters of overlap. A dental overbite is caused by the misalignment of the teeth themselves, such as over-erupted incisors. A skeletal overbite involves an imbalance in the physical structure of the jawbones, typically when the upper jaw is positioned too far forward or the lower jaw is too small. A professional diagnosis often requires X-rays to determine whether the issue is purely dental or involves a skeletal discrepancy.
Functional and Health Implications of Untreated Overbites
Untreated moderate or severe overbites can lead to issues tied to the forces generated during chewing and resting. When the vertical overlap is too great, the lower front teeth may make contact with the palate, or the gum tissue directly behind the upper front teeth, known as palatal impingement. This repeated forceful contact can irritate and damage the gum tissue, potentially leading to inflammation, recession, and periodontal issues.
A severe deep bite concentrates excessive biting forces onto the biting edges of the lower incisors. Over time, this constant friction can cause accelerated and uneven wear, leading to chipping, flattening, and a loss of enamel on the lower teeth. This excessive wear reduces the overall lifespan of the teeth and can lead to increased sensitivity or the need for extensive restorative dental work.
The strain placed on the jaw system by an improper bite can contribute to temporomandibular joint (TMJ) discomfort. When the teeth do not meet correctly, the muscles that control jaw movement must work harder and in an unbalanced way to achieve a functional closure. This muscular tension and misalignment can manifest as chronic headaches, jaw pain, clicking or popping sounds in the joint, and difficulty chewing certain foods. The mechanical stress on the joint and surrounding muscles can significantly impair quality of life.
The Criteria for Mandatory Correction
Orthodontic intervention is indicated when an overbite moves beyond cosmetic concern and becomes a matter of medical necessity, actively causing physical trauma to oral tissues. The most definitive threshold for correction is a complete or impinging overbite that results in measurable tissue damage, such as lower teeth physically digging into the upper gum tissue or palate.
Progressive and rapid tooth wear that threatens the structural integrity of the enamel necessitates treatment to prevent tooth loss or the need for crowns. Severe functional impairment, such as chronic temporomandibular joint pain that does not resolve with conservative treatments, is a strong indicator for correction. In cases where the skeletal discrepancy is profound, surgical intervention may be required to reposition the jaws and establish a stable, non-damaging bite. When a mild overbite is stable, asymptomatic, and not causing any measurable damage, it is acceptable to live with the condition without pursuing active treatment.