An overbite occurs when the upper front teeth overlap the lower front teeth more than they should. While a slight overlap is normal for proper oral function, an excessive overbite is a common type of malocclusion, or “bad bite.” This condition refers specifically to the vertical misalignment of the teeth. It differs from other bite issues like an overjet, where upper teeth protrude forward horizontally, or an underbite, where lower teeth extend past the upper teeth.
Key Visual Features
An overbite is characterized by the noticeable vertical overlap of the upper front teeth over the lower front teeth. In a typical bite, the upper teeth should cover about one-third to one-half of the lower teeth. When an overbite is present, this overlap is significantly greater, sometimes to the extent that the lower front teeth are almost entirely hidden from view when the mouth is closed.
Beyond the vertical overlap, an overbite can also involve horizontal protrusion, known as overjet. This can make the upper front teeth appear more prominent or “buck-toothed.” The combination of excessive vertical and horizontal overlap contributes to the distinct visual characteristics of an overbite. The lower teeth may also appear crowded or crooked due to the pressure and limited space created by the overlapping upper teeth.
Variations in Appearance
Overbites present along a spectrum of severity, influencing their visual manifestation. A mild overbite involves a subtle overlap of the upper teeth, often barely noticeable and typically not causing functional issues.
A moderate overbite shows a more apparent overlap, where the lower teeth are partially obscured but still visible. A severe overbite, also known as a deep bite, is characterized by a significant overlap where the upper front teeth cover nearly all or even completely hide the lower front teeth. In extreme cases, the lower teeth might even bite into the gum tissue behind the upper teeth.
Overbites can also be classified based on their origin: dental or skeletal. A dental overbite is primarily due to the position of the teeth, while a skeletal overbite results from an imbalance in the size or position of the upper and lower jaws. Skeletal overbites, often caused by a smaller or set-back lower jaw, can make the overbite appear more pronounced and contribute to broader facial changes.
Impact on Facial Profile
An overbite affects the overall facial profile. A common consequence is the appearance of a “receding chin” or “weak chin,” where the lower jaw seems set back relative to the upper jaw. This occurs because the excessive overlap of the upper teeth can push the lower jaw backward, creating a less defined jawline.
The upper lip might also appear more prominent due to the forward positioning of the upper front teeth. Individuals with an overbite may experience a strained appearance around the mouth when trying to close their lips comfortably. This tension can arise from the effort to compensate for the dental misalignment. In more severe cases, an overbite can cause the lower face to appear shorter, disrupting the natural balance and proportions of the facial features.
When to Consider Professional Consultation
While the visual aspects of an overbite are often the initial concern, other signs may indicate a need for professional dental evaluation. Difficulty chewing or biting food can be a significant symptom, as an overbite can lead to inefficient chewing and discomfort. Speech issues, such as lisping or trouble pronouncing certain sounds, can also arise due to altered tongue placement caused by the misalignment.
Jaw pain, clicking or popping sounds in the jaw, and stiffness, particularly around the temporomandibular joint (TMJ), are further indicators that an overbite might be causing functional problems. Excessive wear and tear on the teeth, including chipping or enamel erosion, can occur as the upper and lower teeth grind against each other unevenly. A dental professional can accurately diagnose the type and severity of an overbite and recommend appropriate treatment based on individual needs.