A scissor bite is a type of dental misalignment where the upper back teeth sit entirely outside the lower back teeth, so they don’t meet properly when you bite down. Instead of the upper and lower molars interlocking the way they should, the upper teeth pass completely to the outside of the lower ones, almost like the blades of a pair of scissors sliding past each other. It’s one of the rarest forms of malocclusion, affecting roughly 0.3% of people worldwide.
How a Scissor Bite Differs From a Crossbite
The easiest way to understand a scissor bite is to compare it to a crossbite, since the two are often confused. In a normal bite, the outer cusps of your upper molars sit just outside the outer cusps of your lower molars. A crossbite reverses this: the lower teeth end up outside the upper teeth. A scissor bite goes the opposite direction, and further. The upper teeth flare so far outward that the inner cusps of the upper teeth don’t even contact the outer cusps of the lower teeth. The two rows of back teeth miss each other entirely.
This distinction matters because the chewing surfaces never make proper contact. With a crossbite, the teeth still touch, just in the wrong orientation. With a scissor bite, the teeth may barely touch at all on the affected side, which creates a different set of problems over time.
Single Tooth vs. Full Arch
A scissor bite can involve just one tooth or an entire side of the mouth. When only a single tooth sits in this position, clinicians typically call it a scissor bite and treat it as a localized issue. When the problem extends across several teeth on one or both sides, it’s often called a Brodie bite. A Brodie bite usually reflects a broader mismatch in jaw width, where the upper jaw is significantly wider than the lower jaw (or the lower jaw is unusually narrow). Whether the problem is limited to one tooth or spans the full arch shapes both the cause and the treatment approach.
What Causes a Scissor Bite
The root cause is a width mismatch between the upper and lower jaws, and this can be skeletal (the bone itself is the wrong size) or dental (the teeth erupted at the wrong angle even though the jaws are normal). Most of the time, genetics play a significant role. Twin studies have confirmed that jaw width, arch shape, and tooth position all have a strong hereditary component. Research on both identical and fraternal twins found significant genetic influence on arch size and crossbite patterns, though environmental factors also contribute to how the bite ultimately develops.
Beyond genetics, habits during childhood can nudge the bite in the wrong direction. Prolonged thumb sucking, for instance, can widen the upper arch. Abnormal tongue posture or mouth breathing may also alter jaw growth over time. In some cases, a tooth simply erupts along an unusual path, creating a scissor bite on that single tooth without any underlying jaw problem.
What It Feels Like and Why It Matters
A mild scissor bite on one tooth might not cause any obvious symptoms. You may not even know you have it until a dentist points it out on an exam or X-ray. But when multiple teeth are involved, the effects become harder to ignore.
The most immediate issue is chewing. Because the upper and lower teeth don’t meet, your ability to grind food on the affected side drops significantly. You may find yourself favoring one side of your mouth without thinking about it. Over time, this uneven workload can strain the jaw joint on the overworked side.
A scissor bite does not correct itself. It tends to worsen gradually as the unopposed teeth continue to erupt further out of position, a process called overeruption. This can deepen the misalignment and make correction more difficult the longer it’s left alone. Patients with untreated scissor bites commonly develop problems with their temporomandibular joint (the hinge that connects your jaw to your skull), and many report difficulty with side-to-side jaw movements. Uneven wear on the teeth that do make contact is another long-term consequence.
How It’s Diagnosed
Your dentist or orthodontist can usually spot a scissor bite during a visual exam, but understanding its full extent requires imaging. Standard X-rays, including panoramic views and cephalometric radiographs (side-profile skull X-rays), give a two-dimensional picture of how the jaws relate to each other. For more complex cases, cone-beam computed tomography (CBCT) provides a detailed 3D image of the teeth, jaws, and joint structures. These 3D scans allow clinicians to measure the exact width discrepancy between the upper and lower jaws, evaluate each side independently, and plan treatment with much greater precision than flat X-rays allow.
Treatment Options
The right treatment depends on whether the scissor bite involves one tooth, several teeth, or the full arch, and whether the problem is in the teeth alone or in the underlying bone.
Orthodontic Correction
When only a few teeth are affected and the overbite is normal, orthodontic treatment alone is usually enough. The goal is to tip the upper teeth inward (toward the palate) and the lower teeth outward, or to intrude teeth that have overerupted. Braces with cross-elastics (rubber bands that pull the upper teeth inward and the lower teeth outward) are a common approach. In children, removable expansion appliances on the lower arch can widen the lower jaw to match the upper. One case series in young children used a lower expansion appliance over a period of about 21 months to resolve the problem.
Clear aligners combined with temporary anchorage devices (small screws placed in the bone to provide a fixed point for tooth movement) have also been used successfully in adults. The key movements are tipping the malpositioned teeth back into alignment and pushing overerupted teeth back up into the bone.
Surgical Correction
When multiple teeth are involved and the bite is also deep, orthodontics alone may not be practical. The overlapping teeth can physically block the movements needed to open the bite, making treatment extremely slow or impossible. In these cases, orthognathic surgery (jaw surgery) may be recommended. The procedure repositions the upper jaw, the lower jaw, or both to correct the width mismatch at its source. After surgery, braces or aligners fine-tune the final tooth positions. Surgical cases are more involved and require a longer overall treatment timeline, but they address the skeletal root of the problem rather than working around it.
Children vs. Adults
Age matters significantly in scissor bite treatment. In children, the jaws are still growing, which means expansion appliances and growth modification can guide the bone into a better shape relatively easily. Catching a scissor bite in the primary (baby) teeth or early mixed dentition gives the orthodontist the widest range of simple, non-surgical options.
In adults, the bone is mature and far less responsive to expansion forces. Orthodontic camouflage (moving teeth within the existing bone) works well for mild cases, but moderate to severe skeletal discrepancies often require surgery. Treatment in adults also tends to take longer because the bone remodels more slowly. If you’ve been told you have a scissor bite as an adult, getting it evaluated sooner rather than later prevents the overeruption cycle from making correction more complex.