How to Fix a Crossbite: Types, Treatment & Timing

Close your teeth together slowly and pay attention to the last moment before they meet. If your jaw slides sideways to get there, that slide is worth knowing about. It is one of the clearest signs of a crossbite, and it is the part most articles on this topic leave out entirely.

A crossbite is one of the few bite problems where timing genuinely changes the treatment. Caught early in a growing child, it is often corrected with a simple appliance in a matter of months. Left alone into adulthood, the same problem may need a longer or more involved approach. At Montclair Orthodontics in Oakland, board-certified orthodontist Chad Watts, DMD, treats crossbites in children, teens, and adults across the East Bay. This guide explains how to fix a crossbite: what type you may have, how to check for a jaw shift at home, which treatments work at which ages, and when it is worth getting evaluated.

What Is a Crossbite?

In a healthy bite, your upper arch is slightly wider than your lower arch, so the upper teeth close just outside the lower ones all the way around, like a lid sitting over a box. That overlap is what spreads chewing force evenly across your teeth.

A crossbite reverses that relationship somewhere in the mouth. One tooth, a group of teeth, or an entire side closes on the wrong side of its partner. The mismatch is side to side rather than up and down, which is what separates a crossbite from the other common bite problems.

Crossbites are more common than most people expect. A systematic review of healthy children and adolescents found anterior crossbite in roughly 7.8 percent, posterior crossbite in about 9.0 percent, and crossbite involving a functional shift of the jaw in about 12.2 percent.

The Types of Crossbite

Knowing which kind you have matters, because the fix is different for each.

Anterior crossbite

One or more upper front teeth sit behind the lower front teeth when you bite down. Sometimes only a single tooth is involved and the rest of the bite lines up perfectly. This is the type most often confused with an underbite.

Posterior crossbite

One or more upper back teeth close inside the lower back teeth. The upper molars can look tilted inward toward the tongue. Posterior crossbite is frequently caused by a narrow upper jaw and is the type most often treated with expansion.

Unilateral vs. bilateral

A unilateral crossbite affects one side only; a bilateral crossbite affects both. Unilateral posterior crossbites deserve particular attention because they are the ones most likely to come with a jaw shift.

Single-tooth crossbite

Just one tooth erupted on the wrong side of its opposing tooth. These are sometimes correctable with a small, targeted appliance or cross-arch elastics rather than full treatment.

The Jaw Shift Test: A Two-Minute Self-Check

Here is the check that most online crossbite guides skip. Stand in front of a mirror with good light and close your back teeth together very slowly, watching your lower jaw as it moves.

• If your lower jaw slides to one side in the last moment before your teeth meet, that is a functional shift. It usually means one or more teeth are contacting early, and your jaw is detouring sideways to find a position where everything can close.
• Look at your midline: the gap between your two upper front teeth compared with the gap between your two lower front teeth. If they line up when your mouth is open but not when it is closed, that points to a shift.
• Check the back teeth on both sides. If the upper molars close inside the lower ones on one side but not the other, you may have a unilateral posterior crossbite.
• Look at the front teeth. If any upper front tooth sits behind a lower one, that is an anterior crossbite.

Not every crossbite involves a shift. Some involve tooth position or jaw width with no visible slide at all, which is exactly why two bites that look similar in the mirror can need very different treatment. A mirror tells you something may be off. It cannot tell you whether the cause is the teeth, the jaw, or the way the jaw is closing, and that distinction determines the entire treatment plan.

Crossbite vs. Overbite vs. Underbite

These three terms get mixed up constantly, and plenty of people search for "underbite" and leave realizing they actually have an anterior crossbite. The cleanest way to keep them straight is by direction.

The practical difference: an anterior crossbite may involve only one or two teeth with the rest of the bite lining up fine, while a true underbite is a jaw relationship affecting the whole arch. They can look similar in a photo and need very different treatment.

What Causes a Crossbite?

Crossbites usually have more than one contributing factor. The most common include:

• Genetics. Jaw width and tooth size are largely inherited, and a narrow upper jaw often runs in families.
• Mouth breathing. Chronic nasal obstruction encourages a low tongue posture, and the tongue is what normally supports the upper arch from the inside. Over time the upper jaw can develop narrower than it otherwise would.
• Prolonged sucking habits. Thumb sucking or pacifier use past the toddler years can narrow the upper arch and tip teeth out of position.
• Delayed or unusual tooth eruption. A permanent tooth that erupts off course, or a baby tooth that stays in too long, can leave a single tooth in crossbite.
• Early contact from baby teeth. Interference from a deciduous canine is a classic cause of a functional shift in children.
• Crowding. When there is not enough room, teeth can be pushed to the inside of the arch.

Cause matters because it separates a dental crossbite (tooth position), a skeletal crossbite (actual jaw width), and a functional crossbite (a jaw shifting on closure). Each is treated differently, and only an exam with imaging can tell them apart reliably.

Does a Crossbite Need to Be Fixed?

A crossbite is not a dental emergency, and no orthodontist can guarantee what will or will not happen in any individual case. But a crossbite is functional rather than cosmetic, and left untreated it can contribute to:

• Uneven and accelerated wear on the teeth that are taking more than their share of the chewing force.
• Jaw strain and temporomandibular joint discomfort, particularly when a functional shift keeps the jaw closing off-center day after day.
• Asymmetric jaw growth in children, since a jaw that habitually closes to one side is growing in that position.
• Gum recession on teeth positioned outside the normal arch.
• Difficulty chewing efficiently, and in some cases effects on certain speech sounds.
• A higher risk of decay and gum inflammation, because teeth that are out of line are harder to clean well.

The one thing worth being clear about: crossbites do not typically resolve on their own, and posterior crossbites with a functional shift are unlikely to correct without treatment. Waiting and watching is a reasonable plan for some bite issues. For crossbite, waiting mainly narrows the options.

How to Fix a Crossbite: Treatment Options

The right approach depends on the type, the severity, and above all the patient's age. Dr. Watts builds every plan after a full evaluation, but these are the main paths.

Palatal expanders (the primary fix in growing children)

For a posterior crossbite caused by a narrow upper jaw, a palatal expander is the most direct correction available. The appliance is bonded to the upper teeth and has two halves joined by a small screw in the center. Parents turn a tiny key at home, and each turn widens the upper jaw by a fraction of a millimeter. Active expansion typically takes a few weeks, then the appliance stays in place for several more months so new bone can fill in and stabilize the result. Most children wear an expander for a total of about 3 to 6 months.

Children usually feel pressure for a minute or two after a turn and mild soreness in the first days. A temporary gap between the upper front teeth is common during expansion and generally closes on its own.

Braces

Braces handle crossbites that involve tooth position rather than jaw width, and they are frequently used after expansion to finish aligning the bite. Cross-arch elastics worn between an upper and lower tooth are a common way to walk a single tooth back into its correct position. Montclair Orthodontics offers metal braces, clear braces, and mini-diamond braces, along with self-ligating Damon braces for patients who want fewer and shorter adjustment visits.

Invisalign clear aligners

Can Invisalign fix a crossbite? For many mild to moderate dental crossbites, yes. Invisalign clear aligners can tip and rotate teeth back into the correct relationship, often using attachments and elastics to generate the necessary movement. Aligners are a popular choice for adults and teens who want a discreet option, with the usual trade-off: they only work when worn 20 to 22 hours a day. Skeletal crossbites, where the upper jaw itself is too narrow, generally need expansion or braces rather than aligners alone.

Adult crossbite correction

Adults can absolutely have crossbites corrected. What changes is the mechanism. Because the palate is no longer easy to widen with a conventional expander, treatment for an adult crossbite may involve braces or aligners to reposition teeth, a bone-anchored expander that anchors to the bone rather than the teeth, or, for a small number of significant skeletal cases, a combined surgical and orthodontic approach. Most adult crossbites do not require surgery. An evaluation is what tells you which category you fall into.

Why Timing Matters More With Crossbite Than With Other Bite Issues

Expansion works because the upper jaw is not a single fused bone in childhood. It has a growth plate down the middle, the midpalatal suture, that can still be gently separated. That suture generally begins fusing in adolescence, commonly around ages 14 to 16, though this varies considerably from person to person.

The practical takeaway is not that adults have missed their chance. It is that the same crossbite is usually simplest to fix while a child is still growing. This is one of the specific reasons the American Association of Orthodontists recommends a first orthodontic evaluation by age 7, well before most children need braces. Early evaluation frequently means monitoring rather than treatment. But when a posterior crossbite with a jaw shift shows up at age 8, catching it then is meaningfully easier than catching it at 16.

How Long Does Crossbite Treatment Take?

It depends on the type and on the patient. As a general guide, expander treatment in a child commonly runs about 3 to 6 months, though it is often followed later by a comprehensive phase. Correcting a single tooth in crossbite with elastics can take a few months. A full course of braces or aligners addressing a crossbite alongside other alignment issues typically falls in the range of 12 to 24 months. Your orthodontist gives you a specific estimate after examining your bite, because complexity, age, and consistency all move that number.

Whatever the path, retainers are what protect the result. Teeth drift back toward old positions, and corrected bites are no exception.

When to See an Orthodontist

It is worth booking an evaluation if you notice any of the following in yourself or your child:

• Your jaw slides to one side as your teeth come together.
• Upper teeth close inside the lower teeth anywhere in the mouth, front or back.
• Your upper and lower front-tooth midlines do not line up when you bite down.
• Chewing feels lopsided, or you favor one side.
• Noticeable wear, chipping, or gum recession concentrated on one side.
• Jaw soreness, clicking, or facial asymmetry that seems to be developing.
• Chronic mouth breathing or a persistent thumb habit in a young child.
• Your child is 7 or older and has not yet had an orthodontic screening.

An evaluation is diagnostic, not a commitment. Digital X-rays and a clinical exam are what determine whether a crossbite is dental, skeletal, or functional, and that answer is what shapes everything else.

Crossbite Care in Oakland and the East Bay

Families across Oakland, Piedmont, Berkeley, Lamorinda, and Emeryville come to Montclair Orthodontics for crossbite treatment because every stage is handled in one place: early evaluation for young children, expanders and interceptive care, and full treatment for teens and adults. Board-certified orthodontist Chad Watts, DMD, uses an iTero intraoral 3D scanner and digital X-rays to map the bite precisely, including the transverse dimension that a visual exam alone can miss.

The practice is known for fast treatment times, easy financing, lower price points, and top-quality care in a welcoming setting, with a full range of braces and Invisalign options for children, teens, and adults throughout the East Bay.

Insurance and Payment Options

Montclair Orthodontics is in-network with Delta Dental and works to help every patient maximize their orthodontic benefits. Many dental plans provide at least partial coverage for orthodontic appliances, including expanders, though the specifics vary by policy.

We also accept all major insurance carriers, including MetLife, Cigna, Aetna, Guardian, United Healthcare, and Blue Cross Blue Shield. Our team is happy to verify your plan, explain your coverage clearly before treatment begins, and walk you through flexible financing so that cost is not a barrier to a healthy, well-aligned bite.

Frequently Asked Questions

Can a crossbite fix itself?

Generally no. Crossbites rarely self-correct, and a posterior crossbite with a functional jaw shift is unlikely to resolve without treatment. In very young children, an anterior crossbite involving a baby tooth occasionally improves as permanent teeth come in, but this is the exception rather than the rule and is worth having monitored.

What is the best age to fix a crossbite?

There is no single right age, but crossbites caused by a narrow upper jaw are typically easiest to correct while a child is still growing, often between ages 7 and 11. The growth plate in the palate usually begins fusing in the mid-teens, which changes the tools available. That said, crossbites are treatable at any age.

Can Invisalign fix a crossbite?

Often, yes, for mild to moderate crossbites driven by tooth position. Clear aligners can move teeth back into the correct relationship, usually with attachments and sometimes elastics. Crossbites caused by a genuinely narrow upper jaw typically need expansion or braces instead. An evaluation determines which applies.

Is a crossbite the same thing as an underbite?

No, though they are easy to confuse. An anterior crossbite may involve just one or two upper front teeth sitting behind their lower counterparts, with the rest of the bite fine. An underbite is a broader jaw relationship where the lower arch as a whole sits ahead of the upper.

How much does it cost to fix a crossbite?

It depends on the treatment involved. An expander alone is a shorter and less expensive course than comprehensive braces or aligners. Montclair Orthodontics is in-network with Delta Dental, accepts all major carriers, and offers flexible financing. You receive a clear estimate and a benefits review at your consultation.

Does a palatal expander hurt?

Most children describe pressure rather than pain. There is typically a brief tingling or tight sensation for a minute or two after each turn, and mild soreness in the first few days. Soft foods help during that adjustment period. Most kids adapt within about a week.

My child's front teeth developed a gap during expansion. Is that normal?

Yes, and it is usually a sign the appliance is doing its job. A space commonly opens between the two upper front teeth as the jaw widens, and it generally closes on its own once active expansion stops.

Can a crossbite cause jaw pain or TMJ problems?

It can contribute. When a functional shift makes the jaw close off-center thousands of times a day, the joint and surrounding muscles work asymmetrically, which some patients experience as soreness, clicking, or headaches. Jaw pain has many possible causes, so an evaluation is the way to sort out what is driving it in your case.

Can adults fix a crossbite without surgery?

Most adults can. Dental crossbites in adults are commonly corrected with braces or clear aligners, and bone-anchored expanders have made non-surgical widening possible for many adults who previously would not have been candidates. Surgery is reserved for a small number of significant skeletal cases and is only considered after a thorough workup.

Take the First Step Toward a Balanced Bite

A crossbite is common, highly treatable, and one of the bite issues where getting an answer sooner genuinely widens your options. Whether you noticed a jaw shift in your own bite or spotted something in your child's, the useful first step is finding out which type you are dealing with.

This article is for general education and isn't medical advice. A consultation is the best way to get recommendations for your specific smile.