Anterior crossbite
One or more lower front teeth bite ahead of the uppers.
Bite development and function
Crossbite and open bite: when teeth do not meet in the expected relationship
A crossbite can affect one tooth or an entire side. An open bite can involve habits, tooth position or jaw growth. Both deserve more than a visual label.
Diagnosis before applianceThis page supports informed questions. It cannot examine you or determine treatment suitability.
The plain answer
Crossbite and open bite are patterns with multiple causes, so timing and diagnosis matter.
In a crossbite, one or more upper teeth bite inside the lower teeth rather than outside them. Some children shift the jaw sideways to make the teeth fit. In an open bite, upper and lower teeth fail to contact in an area when the rest of the bite closes.
Early review can be useful when growth, a functional shift, thumb sucking, tongue posture or eruption is involved. Aligners or braces may treat selected dental components, while skeletal patterns or persistent habits may need broader planning.
What matters
Key points before you act
Use these as a decision filter at a real consultation.
Posterior crossbite
Upper back teeth sit inside lower teeth on one or both sides.
Open bite
Teeth do not contact in a region, often at the front but sometimes at the back.
Why a functional shift matters
A child may close into an initial tooth contact and then slide the lower jaw to one side. That shift can make the chin and dental midlines appear asymmetric and may influence how the bite develops.
The clinician should check the bite before and after the shift, not simply photograph the final position. A narrow upper arch and a single mispositioned tooth are different problems even though both can be called crossbite.
Information that changes the plan
The assessment should consider:
No single photograph, scan or symptom can answer every one of those questions. The treating provider should explain which records are needed, what each record shows and how the findings change the plan.
- which teeth are involved and whether the pattern is unilateral or bilateral;
- whether a jaw shift occurs during closure;
- arch width, growth pattern and facial symmetry;
- thumb, finger, tongue or airway-related habits;
- trauma, gum recession, wear or chewing difficulty.
Early correction, habit management or comprehensive treatment
Some crossbites are treated early to remove a functional interference or address arch width while growth remains. Some open bites improve when a habit stops; others reflect skeletal growth and require longer-term planning.
Ask what component the proposed appliance addresses and what happens if the habit, growth pattern or tongue posture remains. A device cannot be evaluated separately from the cause.
The appropriate option can change after an examination. Use this comparison to prepare questions, not to self-prescribe treatment.
What families and adults should notice
Note whether the jaw shifts, one side chews more, front teeth cannot bite food, or teeth are wearing unevenly. In adults, new open bite or tooth movement can also be associated with periodontal or joint changes and should be assessed.
Treatment may require elastics, attachments, fixed appliances, expansion or referral. Patient cooperation can be especially important when elastics or habit control are prescribed.
- Take a short video of an intermittent jaw shift if it is hard to reproduce in the office.
- Report thumb or finger habits honestly; the goal is planning, not blame.
- Ask how the provider will measure correction and stability.
Questions to take to a consultation
- Is the problem dental, skeletal, functional or habit-related?
- Does the jaw shift when the teeth close?
- Is timing important because the patient is still growing?
- What role do braces, aligners, expansion, elastics or habit management play?
- When should a certified orthodontic specialist or another professional be involved?
Common questions
Questions patients ask
Can a crossbite affect facial symmetry?
A functional shift can make the jaw appear asymmetric, which is one reason early assessment may be useful.
Will an open bite close when thumb sucking stops?
Some dental open bites improve after the habit stops, but the result depends on age, duration, tongue posture and jaw pattern.
Can aligners treat crossbite?
Selected dental crossbites may be treated with aligners and auxiliaries. Arch-width and skeletal problems require case-specific evaluation.
Primary references
Sources used for this guide
External sources can change. Verify current regulatory and product information at the linked publisher.
- When should a child see an orthodontist? ↗American Association of Orthodontists
- Dentist licences and recognized specialties in British Columbia ↗British Columbia College of Oral Health Professionals
- Search the BCCOHP public registry ↗British Columbia College of Oral Health Professionals