An overbite describes the vertical overlap of your upper front teeth over your lower front teeth when your jaw is closed. While many people associate an overbite with a dental problem, a certain degree of this overlap is common and functionally normal. This natural positioning plays a role in various oral functions.
Understanding a Healthy Overbite
A healthy or normal overbite involves the upper front teeth covering the lower front teeth by about 2 to 4 millimeters. This measurement can also be expressed as a percentage, usually around 20% to 30% coverage of the lower incisors. In a balanced bite, the lower front teeth lightly touch the back surfaces of the upper front teeth.
This degree of overlap is beneficial for several reasons. It helps protect the lower front teeth from excessive wear that could occur if they directly contacted the upper teeth during chewing. A healthy overbite also aids in efficient chewing by providing proper leverage and stability. It contributes to clear speech and helps maintain the overall alignment of the jaw and facial profile.
When an Overbite Requires Attention
An overbite becomes problematic when the vertical overlap is excessive, often referred to as a “deep bite.” This occurs when the upper front teeth cover the lower front teeth beyond the normal range, commonly by 4-5mm or more, or upwards of 30% coverage. In severe cases, the upper teeth may even bite into the gum tissue behind the lower front teeth or the lower teeth bite into the roof of the mouth, causing discomfort and tissue damage.
Such deep bites can lead to several issues, including accelerated wear on both upper and lower front teeth, making them shorter and flatter. This wear can expose deeper tooth layers, increasing sensitivity to temperature and making teeth more susceptible to cavities, chipping, or cracking. Other problems include jaw pain, chronic headaches, clicking or popping sounds in the jaw, and difficulty with chewing, especially biting into certain foods.
Speech impediments can also occur as tooth positioning alters tongue posture. Contributing factors can include genetics, an underdeveloped lower jaw, prolonged thumb-sucking or pacifier use, and teeth grinding.
Options for Correcting an Overbite
When an overbite is deemed excessive or problematic, various orthodontic treatments can help achieve proper alignment. Traditional braces, consisting of brackets and wires, are a common and effective method for repositioning misaligned teeth and correcting overbites. They apply continuous pressure to move teeth into their correct positions.
Clear aligners, such as Invisalign, offer a less visible alternative, using a series of custom-made, transparent trays to gradually shift teeth. While effective for mild to moderate overbites primarily caused by tooth positioning, aligners may have limitations in severe cases involving jaw misalignment.
In instances of severe skeletal overbites, where the issue stems from jaw structure, orthognathic surgery may be recommended in conjunction with orthodontic treatment to reposition the jaw bones. A consultation with an orthodontist is important for a proper diagnosis and personalized treatment plan.