A deep bite is an orthodontic condition where the upper front teeth overlap the lower front teeth too much vertically. Most people have some overlap, and 2 to 4 millimeters is considered normal. A deep bite starts when that overlap exceeds about 4 millimeters, or when the upper teeth cover more than 30% of the lower teeth. It’s one of the most common bite problems orthodontists treat, and depending on severity, it can cause gum damage, excessive tooth wear, and discomfort.
How a Deep Bite Differs From an Overjet
People often confuse overbites and overjets, but they describe two different measurements. A deep bite (overbite) is a vertical problem: the upper teeth drop down too far over the lower teeth. An overjet is a horizontal problem: the upper teeth stick out forward past the lower teeth, sometimes called “buck teeth.” You can have one without the other, or both at the same time. The distinction matters because each requires a different treatment approach.
Mild, Moderate, and Severe Deep Bites
Orthodontists grade deep bites by how much of the lower front teeth disappear behind the upper ones. A mild deep bite (grade 1) means the upper teeth cover one-third to less than two-thirds of the lower incisors. A moderate deep bite (grade 2) covers two-thirds up to the full length of the lower teeth. A severe deep bite (grade 3) means the upper teeth overlap the entire visible portion of the lower incisors, and in some cases, the lower teeth bite into the roof of the mouth.
What Causes a Deep Bite
Deep bites fall into two broad categories: skeletal and dental. The cause shapes how difficult the correction will be.
Skeletal Deep Bite
A skeletal deep bite stems from the way the jawbones grew. In these cases, the lower jaw rotates upward and forward during development, reducing the lower portion of the face height. People with skeletal deep bites sometimes have what clinicians call “short face syndrome,” where the lower third of the face looks compressed. The mismatch between the upper and lower jawbones, convergent rotation of the jaw bases, or a short vertical section of the lower jaw can all contribute. Because the bones themselves are involved, skeletal deep bites are generally harder to correct and more likely to need advanced treatment.
Dental Deep Bite
A dental deep bite is caused by the teeth themselves rather than the underlying bone structure. The front teeth may have erupted too far (overeruption), or the back teeth may not have erupted enough (undereruption), or both. When back teeth sit lower than they should, the jaw closes further than normal, pushing the front teeth into deeper overlap. This type doesn’t usually change the facial profile the way a skeletal deep bite does, and it tends to respond well to orthodontic treatment alone.
Many deep bites involve a combination of skeletal and dental factors. An orthodontist uses X-rays and measurements of facial landmarks to determine how much each component contributes.
Health Risks of an Untreated Deep Bite
A mild deep bite may cause no symptoms at all. But as the overlap increases, the risks become more concrete.
Gum and Soft Tissue Damage
In severe deep bites, the lower front teeth can press directly into the gum tissue behind the upper teeth, causing chronic irritation and recession of the palatal gums. The reverse can also happen: the edges of the upper front teeth can dig into the gum tissue in front of the lower teeth. One case report documented a patient with a 7-millimeter deep bite whose gum tissue on the lower front teeth had receded all the way down to the roots. This kind of damage is progressive, meaning it worsens over time if the bite isn’t corrected.
Accelerated Tooth Wear
Deep bites significantly increase the rate at which teeth grind against each other. A study of 275 participants found a strong statistical link between deep bites and dental attrition. Among those with moderate to severe deep bites, 38% showed extensive wear on their teeth, compared to much lower rates in people with normal bites. The odds of developing significant wear were about four times higher in the deep bite group. Over years, this wear can flatten the biting surfaces of teeth, expose the softer layer beneath the enamel, and shorten the visible crowns.
Jaw Joint Issues
The relationship between deep bites and jaw joint disorders remains debated. Some research has found an association between extreme deep bites and jaw pain or clicking, but most reviews conclude that a deep bite alone doesn’t cause temporomandibular joint problems. Other factors like stress, grinding habits, and joint anatomy play a larger role. Still, a severe deep bite can restrict the natural forward and side-to-side movement of the lower jaw, which some people experience as stiffness or discomfort.
How Deep Bites Are Corrected
The goal of treatment is to reduce the vertical overlap to a normal range, typically around 2 millimeters. Treatment time ranges from about 6 months for mild cases to up to 3 years for severe ones. The method depends on what’s causing the deep bite and how significant it is.
Braces and Bite Turbos
Traditional braces remain the most common approach. For deep bite correction specifically, orthodontists often add small raised platforms called bite turbos (or bite ramps) to the back surface of the upper front teeth. These are small bumps, up to 3 millimeters thick, that prevent the back teeth from fully touching when you bite down. This separation allows the back teeth to gradually erupt into a better position while the front teeth are pushed slightly upward, reducing the overlap. The combination of leveling the curve of the lower arch and adjusting tooth positions vertically is what opens the bite.
Clear Aligners
Clear aligners can also correct deep bites, though they work somewhat differently. The aligner protocol for deep bite correction typically involves pushing the front teeth upward (intrusion) while encouraging the back teeth to come down slightly (extrusion). Precision bite ramps built into the aligners serve the same function as bite turbos in braces. In one study using a specific deep bite protocol, patients achieved an average overbite correction of 4.1 millimeters, bringing their overlap down to about 1.1 millimeters. Lower front teeth were pushed up by about 1.8 millimeters, and lower back teeth were brought down by 1.2 to 1.7 millimeters.
Earlier research suggested that clear aligners corrected less overbite than braces (1.3 millimeters versus 2.0 millimeters in one comparison), but newer protocols with bite ramps and optimized attachment designs have narrowed that gap considerably. Patients typically wear aligners 22 hours per day, changing to a new set weekly.
Jaw Surgery
Surgery is reserved for severe skeletal deep bites where the jaw structure itself needs to be repositioned. If the deep bite is primarily caused by abnormal jaw growth rather than tooth position, braces or aligners alone can’t fully fix it. Surgical correction involves repositioning one or both jaws to establish proper vertical proportions. This is typically combined with orthodontic treatment before or after the procedure. Most people with deep bites won’t need surgery, but adults with significant skeletal discrepancies and a compressed lower face are the most likely candidates.
Why Timing Matters
In children, a deep bite can sometimes be intercepted during growth. Because skeletal deep bites involve the rotation and growth pattern of the lower jaw, early treatment during the growth spurt can redirect jaw development and reduce the severity of the problem. In adults, the bones are no longer growing, so treatment relies entirely on moving teeth or surgically repositioning the jaws. The soft tissue and tooth damage caused by a deep bite is cumulative. Gum recession doesn’t reverse on its own, and worn enamel doesn’t grow back, so earlier correction generally means less permanent damage.