Crossbite, Overbite, Underbite, Open Bite: A Complete Visual Guide for Parents

By Dr. Mohamed Hasab — Specialist Orthodontist, myPediaclinic Dubai

Every week, parents bring their children to me pointing at their child’s mouth, worried. “His teeth don’t fit together properly.” “Her front teeth stick out.” “My daughter’s jaw is crooked when she bites down.” They’ve noticed something. They’re not sure what it is. They don’t know if it matters.

The answer, in most cases: yes, it matters — and yes, we can usually fix it. But first, you need to understand what kind of bite problem you’re seeing.

This guide walks you through the major types of bite problems (malocclusions) in children. What they look like. What causes them. When they need treatment. When they’ll resolve on their own. After reading this, you’ll have a clearer understanding of your child’s bite and whether an orthodontic consultation makes sense.

First: What Is a “Normal” Bite?

A normal bite has several key features:

• Upper front teeth slightly overlap lower front teeth (about 2–3 mm vertical overlap, 2–3 mm horizontal overlap)
• Upper molars fit neatly over lower molars
• Teeth touch evenly when biting down
• Jaw midline (centre) aligns with facial midline
• No spacing or crowding
• Teeth point straight up and down (not tilted or rotated)

When any of these features is off, we have some form of malocclusion.

Type 1: Overbite (Deep Bite)

What It Looks Like

An overbite means the upper front teeth cover too much of the lower front teeth when biting down. Normal overbite is about 20–30% coverage. In an excessive overbite, you might not see the lower teeth at all when the mouth is closed.

Severe overbites can be so pronounced that the lower front teeth actually bite into the roof of the mouth (palate), causing pain and tissue damage.

What Causes It

• Jaw size discrepancy (upper jaw grows too large, or lower jaw too small)
• Thumb sucking or pacifier use continuing past age 3–4
• Tongue thrust habits
• Premature loss of back baby teeth allowing other teeth to over-erupt
• Genetic factors

When It Needs Treatment

• Lower teeth bite into palate (causes tissue damage)
• Excessive wear of front teeth
• Affects chewing or speech
• Causes jaw joint pain
• Significant aesthetic concern
• Creates difficulty with orthodontic treatment later

Treatment Approach

Overbite correction varies by age and severity:

• Early intervention (age 7–10): Growth modification appliances, headgear, functional appliances (Herbst, Twin Block)
• Adolescent treatment: Braces or clear aligners with specific techniques to reduce overbite
• Adult treatment: More challenging as growth is complete; may require surgery in severe cases

Early treatment is dramatically more effective than waiting. The window of opportunity during growth is priceless.

Type 2: Underbite (Reverse Bite / Class III)

What It Looks Like

An underbite is when the lower front teeth bite in FRONT of the upper front teeth — the opposite of normal. In mild cases, the lower and upper teeth meet edge-to-edge. In severe cases, the lower jaw noticeably protrudes.

A child with a pronounced underbite often has a characteristic facial profile with a prominent chin.

What Causes It

• Genetic jaw size — most common cause
• Large lower jaw or small upper jaw (often genetic)
• Tongue positioned too far forward and low
• Mouth breathing affecting facial growth
• Certain syndromes (less common)

When It Needs Treatment

Underbites almost always need treatment. They rarely self-correct. And because they involve jaw growth, the timing of treatment matters enormously.

Treatment Approach

• Very early treatment (age 5–8): Can sometimes redirect growth using appliances like reverse-pull headgear or face masks. This is the window for maximum impact.
• Late childhood/early teen (age 9–13): Braces combined with growth modification. More challenging but often effective.
• Adult treatment: Often requires jaw surgery (orthognathic surgery) combined with orthodontics. Significantly more invasive than early treatment.

Underbite is the most compelling case for early orthodontic evaluation. Catching it at age 7–8 versus age 15–16 can be the difference between appliance therapy and jaw surgery.

Type 3: Crossbite (Unilateral or Bilateral)

What It Looks Like

A crossbite is when some of the upper teeth bite INSIDE the lower teeth, instead of outside. There are several patterns:

• Anterior crossbite: One or more front teeth are behind the opposing teeth (looks like a single-tooth underbite)
• Posterior crossbite (unilateral): Upper back teeth on one side bite inside the lower back teeth
• Posterior crossbite (bilateral): Both sides affected

Crossbites often cause the lower jaw to shift sideways when the child closes their mouth — this is called a “functional shift” and is a serious concern.

What Causes It

• Narrow upper jaw
• Wide lower jaw
• Thumb sucking or pacifier use
• Mouth breathing (reduces normal palatal development)
• Tongue thrusting
• Retained baby teeth blocking permanent teeth
• Genetic factors

When It Needs Treatment

Crossbites should almost always be treated, often early:

• They cause uneven tooth wear
• They can shift the jaw and cause facial asymmetry if untreated
• They may lead to TMJ (jaw joint) problems
• They interfere with normal chewing
• They can create a shifted jaw that becomes permanent

Treatment Approach

• Posterior crossbite: Palatal expander (for bilateral), crossbite elastics or expander (for unilateral). Best results ages 7–12 when palatal sutures are still flexible.
• Anterior crossbite: May resolve with growth or require simple appliances. Sometimes bracket-and-wire treatment.
• Adult crossbites: More complex; may require surgical expansion.

Crossbite correction in early childhood is one of orthodontics’ success stories. Simple expansion appliances, worn for a few months, often resolve the problem permanently.

Type 4: Open Bite

What It Looks Like

An open bite is when certain teeth don’t touch when the mouth is closed — there’s a visible gap between upper and lower teeth while other teeth are in contact.

• Anterior open bite: Front teeth don’t touch. The child can’t bite through food with their front teeth. Commonly seen with tongue thrusting or thumb sucking.
• Posterior open bite: Back teeth don’t touch. Less common but can affect chewing efficiency.

What Causes It

• Prolonged thumb sucking or pacifier use (most common cause)
• Tongue thrust habit (pushing tongue against teeth when swallowing)
• Mouth breathing
• Enlarged tonsils or adenoids forcing tongue forward
• Skeletal factors (jaw growth pattern)
• Trauma during tooth development

When It Needs Treatment

• Always needs evaluation — rarely self-corrects once permanent teeth are in
• Affects ability to bite food properly
• Affects speech (certain sounds require front teeth contact)
• Aesthetic concern
• Often indicates underlying habit or airway issue that needs addressing

Treatment Approach

• First: Address the cause. Stop thumb sucking, treat mouth breathing, address tongue thrust, evaluate tonsils/adenoids.
• Habit appliances to help break thumb/tongue habits
• Orthodontic treatment (braces or clear aligners) to close the bite
• In severe cases: Surgical correction

Treating only the teeth without addressing the underlying habit usually fails — the open bite returns. This is why a comprehensive approach is essential.

Type 5: Crowding

What It Looks Like

Crowding is when there isn’t enough space in the jaw for all the teeth. Teeth emerge in rotated, overlapping, or displaced positions. Some teeth may not be able to erupt at all (impacted teeth).

What Causes It

• Jaw size too small relative to tooth size
• Premature loss of baby teeth (neighbours drift into the space)
• Large teeth inherited from one parent, small jaw from the other
• Tongue position affecting jaw development
• Mouth breathing causing narrower jaw development

When It Needs Treatment

• Significant crowding affects oral hygiene (crowded teeth are harder to clean)
• Increases cavity risk
• Can cause gum disease in overlapping areas
• Aesthetic concerns
• Impacted teeth (trapped below gum line) need attention

Treatment Approach

• Early intervention (age 7–10): Create space through expansion, serial extractions, or other techniques
• Adolescent treatment: Braces or aligners, sometimes with extractions of permanent teeth to create space
• Mild crowding may need only minor correction
• Severe crowding may require extracting some teeth to allow others to align properly

Type 6: Spacing (Gaps)

What It Looks Like

Excessive spaces between teeth. May be a single gap between front teeth (diastema) or generalised spaces throughout.

What Causes It

• Jaw size too large relative to tooth size
• Missing teeth (developmentally)
• Small teeth
• High frenum (the tissue between upper lip and gum) can cause a specific diastema
• Tongue thrusting habits
• Normal in young children with baby teeth — spaces prepare for larger permanent teeth

When It Needs Treatment

• Aesthetic concerns
• Food trapping
• Difficulty with speech (rare)
• Self-esteem impact

Spaces between baby teeth are usually normal and don’t need treatment. Spaces in permanent teeth often do.

Treatment Approach

• Braces or aligners to close spaces
• Frenectomy (removing abnormal frenum) if that’s causing the diastema
• Composite bonding or veneers to make teeth appear larger (after orthodontic treatment)
• Replacement of missing teeth

Type 7: Missing Teeth (Hypodontia/Oligodontia)

What It Looks Like

Some permanent teeth never develop. Common missing teeth include second premolars, upper lateral incisors, and wisdom teeth.

What Causes It

• Genetic factors
• Some syndromes (ectodermal dysplasia, Down syndrome)
• Trauma to developing tooth bud
• Sometimes unknown

When It Needs Treatment

Always needs evaluation. Options include:

• Space management (close space with orthodontics, or maintain for future replacement)
• Prosthetic replacement (bridge, implant in adulthood)
• Orthodontic movement of neighbouring teeth to fill the space

Type 8: Extra Teeth (Supernumerary)

What It Looks Like

Extra teeth beyond the normal 20 baby teeth or 32 permanent teeth. Most common location is between the upper front teeth.

When It Needs Treatment

Usually removal is recommended, especially if:

• The extra tooth prevents normal teeth from erupting
• It causes crowding
• It changes the bite

Combined Problems: The Real Picture

Most children with orthodontic issues don’t have just one problem. Typically we see combinations — crowding with crossbite, overbite with spacing, underbite with an open bite. Real orthodontic diagnosis requires looking at the whole picture.

This is why self-diagnosis from photos isn’t ideal. What looks like a simple overbite may be an overbite plus crowding plus a developing jaw issue. A comprehensive orthodontic evaluation sorts through everything.

When Should Bite Problems Be Evaluated?

The American Association of Orthodontists recommends orthodontic evaluation by age 7. This is for several reasons:

• Most permanent teeth are beginning to erupt
• Growth patterns are clear
• Early problems can be caught before they worsen
• Many early interventions are much simpler than late ones
• Some problems (like crossbites, underbites, or jaw discrepancies) treat best at this age

Age 7 doesn’t mean every child needs treatment at age 7 — most don’t. It means an evaluation at age 7 allows us to:

• Identify problems requiring early intervention
• Reassure families where everything is normal
• Plan optimal timing for any needed treatment

Self-Correction: Which Problems Resolve?

Some bite issues in young children will self-correct:

• Small spaces between baby teeth (normal)
• Slight rotations of newly erupting teeth
• Mild front tooth flaring that resolves as back teeth come in

Many others won’t:

• Underbite (rarely self-corrects)
• Significant crossbite
• Open bite with ongoing habit
• Severe crowding
• Missing teeth

The key distinction is whether the cause is resolving (habit stopping, growth continuing normally) or persistent (skeletal, hereditary). An orthodontic evaluation clarifies which.

Frequently Asked Questions

Q: My child is 5 and has an obvious underbite. Is it too early for treatment?

Not at all — age 5 is actually ideal for beginning evaluation and potentially treatment of underbite. Growth modification appliances work best in this age range. Book an orthodontic consultation.

Q: My child’s teeth are crowded but they still have baby teeth. Do we wait?

Crowding in baby teeth usually becomes worse crowding in permanent teeth. Early evaluation can identify interventions that create space or prevent worsening. Don’t wait for all permanent teeth to come in — often by then you’ve missed the best window.

Q: How can I tell if my child has a crossbite?

Watch your child bite down. The upper teeth should be slightly outside the lower teeth on both sides. If any upper teeth are inside the lower teeth, that’s a crossbite. Watch whether the jaw shifts sideways when they close their mouth.

Q: My child had a thumb-sucking habit and now has an open bite. Will it fix itself?

Sometimes, if thumb sucking stopped before permanent teeth erupted and the habit is truly gone. Often, open bite persists even after the habit stops — particularly in children over age 6 when the habit ended. Orthodontic evaluation determines whether intervention is needed.

Q: Can braces fix a jaw alignment issue or is that something else?

Braces alone can correct tooth position. For jaw discrepancies in growing children, we can guide jaw growth with appliances. For significant skeletal issues in adults, surgery may be combined with braces.

Q: When should my child see an orthodontist vs a pediatric dentist?

Pediatric dentists manage overall oral health. Orthodontists specialise in tooth and jaw alignment. Your pediatric dentist will refer you to an orthodontist when alignment issues need specialist attention — typically around age 7 for first evaluation.

Q: How much does orthodontic treatment cost in Dubai?

Costs vary widely by treatment complexity:

• Early interceptive treatment: AED 5,000–15,000
• Full braces: AED 15,000–35,000
• Clear aligners: AED 20,000–45,000
• Complex cases with surgery: AED 40,000+

Many insurance plans cover partial costs. We discuss detailed estimates during consultation.

Q: Can my child wait until adulthood for orthodontic treatment?

For some problems, yes. For others, adult treatment is significantly more complex and expensive. Growth-modification approaches only work during childhood. Early intervention is usually wiser for jaw-related issues.

The Bottom Line

Bite problems come in many forms. Some are minor cosmetic concerns. Others affect chewing, speech, jaw joint health, and facial development. Some resolve on their own. Most don’t.

The only way to know which category your child falls into is a professional orthodontic evaluation. At myPediaclinic Dubai, I offer comprehensive orthodontic consultations for children age 7 and above — sometimes earlier when specific concerns are apparent.

If you’ve been wondering about your child’s bite, book a consultation. We’ll examine carefully, take appropriate imaging, explain what we see, and give you clear guidance on whether treatment is needed and when.

Dr. Mohamed Hasab is a Specialist Orthodontist at myPediaclinic Dubai. He works with children, teenagers, and adults on the full range of orthodontic concerns — from simple alignment issues to complex combined orthodontic/surgical cases.