A slight overlap between the upper and lower teeth is a standard feature of a healthy, functional bite, known as dental occlusion. This natural arrangement allows for efficient chewing and protects the soft tissues of the mouth. While a small amount of overlap is expected, excessive overlap is a form of misalignment that can cause oral health issues. Understanding the difference between a normal bite and one that requires attention is important for maintaining long-term dental health.
Understanding What an Overbite Is
An overbite is a type of malocclusion, or “bad bite,” describing the vertical overlap between the upper and lower front teeth when the jaw is closed. In a normal bite, the upper teeth should cover approximately 20% to 30% of the lower teeth, ideally measuring between 2 to 4 millimeters of vertical overlap. This vertical relationship is distinct from overjet, which measures how far the upper front teeth protrude horizontally. When the vertical overlap exceeds 4 millimeters, the condition is classified as an excessive overbite or a deep bite, indicating a potential functional problem. The goal of orthodontic care is to ensure the overlap remains within the healthy 2 to 4-millimeter range for optimal function and stability.
Common Causes of Overbite Development
The origin of an overbite traces back to two categories: skeletal factors and environmental influences. Skeletal overbites are primarily genetic, resulting from inherited differences in the size or position of the upper and lower jaws. This often leads to a lower jaw that is smaller or underdeveloped compared to the upper jaw.
Environmental Factors
Environmental factors, such as persistent habits like prolonged pacifier use or thumb-sucking past age four, also contribute significantly. These habits exert pressure that can push upper teeth forward or prevent the lower jaw from growing correctly. Other contributors include tongue thrusting and the premature loss of primary or adult back teeth, which alters the bite balance. Understanding the underlying cause guides the selection of the most effective treatment approach.
Identifying When Intervention Is Necessary
While a slight overbite is normal, excessive overlap becomes a functional problem when it causes physical symptoms or damage. A primary indicator is excessive wear on the lower front teeth, which grind against the back surfaces of the upper teeth. This friction wears down enamel, increasing susceptibility to decay and sensitivity. A severe deep bite can also cause trauma to soft tissues, sometimes resulting in the lower teeth biting directly into the gum tissue behind the upper front teeth. This injury can lead to irritation, inflammation, and gum recession.
Systemic and Functional Issues
A misaligned bite can also strain the temporomandibular joints (TMJ). This strain may manifest as chronic jaw soreness, headaches, or difficulty opening and closing the mouth. Functional limitations also include difficulty chewing and the development of speech impediments, such as a lisp. Early consultation with an orthodontist is recommended around age seven to intercept issues before they become severe.
Overview of Corrective Treatment Options
The approach to correcting an overbite depends on the patient’s age, severity, and cause of the malocclusion. For children whose jaws are still developing, early intervention (Phase I treatment) focuses on guiding jawbone growth. Appliances like palate expanders, specialized bite plates, or habit appliances modify the jaw relationship and stop contributing behaviors like thumb-sucking. This early guidance often simplifies or shortens later treatment.
Treatment for Adolescents and Adults
For adolescents and adults, the most common corrective methods are traditional braces and clear aligners. Braces, which use brackets and wires, are effective for moderate to severe cases, often utilizing elastic bands to reposition the jaw. Clear aligners are a discreet option for mild to moderate overbites, shifting the teeth into correct alignment using continuous pressure. In the most severe skeletal cases, where the jaw discrepancy is pronounced, treatment may require orthognathic surgery. This procedure physically repositions the upper and lower jaws into a balanced alignment and is typically combined with orthodontic treatment.