Overbite vs. Underbite: Causes, Problems, and Treatment Options Compared

An overbite or underbite might seem like a cosmetic issue, but they're actually structural bite problems that can affect your health, comfort, and appearance. Here's everything you need to know about recognizing, understanding, and treating them.

What's the Difference?

Overbite: Your upper front teeth overlap your lower front teeth too much (vertically). Normal is 2–3mm overlap; anything over 5mm is considered excessive.

Underbite: Your lower front teeth extend beyond your upper front teeth (reverse of normal). Your lower jaw appears to jut forward.

Both are malocclusions (bite misalignments)—but they require different treatment approaches.

Overbite vs. Underbite Comparison Table

Overbite: Causes and Problems

Causes of Overbite

• Genetic jaw structure: Small lower jaw or large upper jaw
• Tooth size mismatch: Large upper teeth relative to jaw size
• Thumb sucking: Prolonged habit pushes teeth forward
• Tongue thrust: Pushing tongue forward habitually
• Sleep apnea: Changes growth patterns
• Missing lower teeth: Upper teeth tilt into the gap
• Poor posture: Forward head posture affects bite development

Problems Caused by Overbite

• Uneven wear: Upper teeth wear unevenly; lower teeth bear too much pressure
• Lower tooth damage: Excess pressure can crack or break lower teeth
• Gum recession: Lower teeth may recede from pressure
• TMJ dysfunction: Abnormal pressure on jaw joints; clicking, pain
• Headaches: Muscle tension from compensating for bite
• Speech issues: Possible lisp if severe
• Appearance: Self-consciousness about protruding upper teeth
• Chewing difficulty: Certain foods hard to chew comfortably

Overbite Treatment by Severity

Mild Overbite (3–5mm overjet): - Observation in young children (may self-correct) - Braces if cosmetically concerning - Invisalign if good candidates - Cost: $3,000–$7,000 - Timeline: 12–24 months

Moderate Overbite (5–10mm): - Braces or Invisalign required - May need tooth extractions to create space - Upper jaw expansion possible - Cost: $4,000–$8,000 - Timeline: 18–30 months

Severe Overbite (10mm+): - Orthodontics + surgical correction (orthognathic surgery) - Upper jaw advancement or lower jaw expansion - Cost: $15,000–$35,000 (includes surgery) - Timeline: 24–36 months (surgery + braces)

Underbite: Causes and Problems

Causes of Underbite

• Genetic jaw structure: Large lower jaw or small upper jaw
• Skeletal discrepancy: Facial bones grew disproportionately
• Cleft lip/palate: Can create jaw development issues
• Tongue thrust: Pushes lower jaw forward during development
• Early extraction: Missing upper teeth affects growth
• Sleep apnea: Changes airway anatomy and jaw growth
• Injury: Childhood jaw trauma affecting growth

Problems Caused by Underbite

• Uneven tooth wear: Upper teeth wear excessively
• Gum recession: Upper front teeth may recede from wear
• TMJ dysfunction: Common with underbites; jaw pain, clicking
• Speech: Possible speech changes (sounding like "d" instead of "th")
• Appearance: Self-consciousness about protruding lower jaw
• Chewing: Difficulty with hard/crunchy foods
• Mouth breathing: Can contribute to underbite; airway issues
• Sleep quality: May affect sleep if related to airway

Underbite Treatment by Severity

Mild Underbite (1–3mm reverse overjet): - Monitor in young children (sometimes self-corrects by age 10) - Possible functional therapy - Braces if persists past age 10–12 - Cost: $3,000–$7,000 - Timeline: 12–24 months

Moderate Underbite (3–6mm): - Braces required; usually phase 1 (early) + phase 2 (fixed) - May need upper jaw expansion - Possible extraction of lower teeth - Cost: $5,000–$10,000 - Timeline: 24–36 months (includes early phase)

Severe Underbite (6mm+): - Orthognathic surgery required for best results - Lower jaw reduction or upper jaw advancement - Braces before and after surgery - Cost: $15,000–$40,000 - Timeline: 36+ months (surgery + braces)

Treatment Options Across Severity Levels

When to Start Treatment

For overbite: - Monitor from childhood (age 5+) - Start braces around age 11–13 for moderate/severe cases - Early treatment (phase 1) possible but not always necessary - Can treat any age (even adults), but jaw surgery needed if severe and adult

For underbite: - Monitor closely from age 5–7 (when underbite often appears) - Early treatment (phase 1) recommended if moderate/severe - Phase 2 (fixed braces) typically starts age 11–13 - Can treat any age, but earlier correction usually better (less severe surgery needed if caught early)

Early vs. Adult Treatment

Early Treatment (Age 5–12): - Easier to guide jaw growth - Less need for surgery or extractions - Shorter overall treatment time - More effective for severe underbites - Possible 2-phase approach (expander, then braces)

Adult Treatment (18+): - Jaw growth is complete; can't change skeletal structure - May need surgical correction for severe cases - Single phase of braces (simpler, but more invasive if surgery needed) - Often still excellent results even in adulthood - Teeth move at same speed as children

Retainers After Treatment

Whether you had braces for overbite or underbite:

• First 6 months: Wear 24/7
• Months 6–12: Wear nightly
• Year 1+: Wear several nights weekly long-term

Bite problems have high relapse if retainers aren't worn. Many adults need permanent bonded retainers on lower teeth.

Key Takeaway

Overbite and underbite both need treatment if moderate to severe, but treatment approaches differ. Overbites are more common and usually easier to treat; underbites benefit from early intervention.

Orthodontist vs. General Dentist

Orthodontist recommended for: - Moderate to severe cases - Cases requiring phase 1 therapy - Severe cases possibly needing surgery - Complex tooth/jaw interactions

General dentist acceptable for: - Very mild cases - Follow-up retention after orthodontist - Monitoring children

Most bite problems warrant orthodontist consultation, even if final treatment is simple.

Can These Problems Go Away Untreated?

• Mild overbite: 30–40% resolve naturally by age 12 without treatment
• Moderate overbite: Usually worsens without treatment (teeth wear, TMJ issues)
• Mild underbite: 20–30% improve naturally by age 12
• Moderate underbite: Usually worsens; needs treatment for best outcome
• Severe cases (either): Rarely improve naturally; typically worsen

Most bite problems benefit from early treatment. Waiting usually makes them worse.

Insurance Coverage

• Braces for bite problems: Often 50% covered by dental insurance
• Orthognathic surgery: Often covered if medically necessary (documented jaw dysfunction)
• Cosmetic-only treatment: Usually not covered
• Early phase (expanders): Sometimes covered if functional necessity documented

Check your specific plan.

Final Thoughts

Overbite and underbite are common, treatable bite problems. The key is catching them early and getting appropriate treatment from an orthodontist. Early intervention prevents more serious issues, reduces treatment time, and eliminates the need for surgery in many cases.

If your child or you have a noticeable overbite or underbite, a consultation with an orthodontist is worthwhile. Many bite problems are fixable with relatively straightforward braces treatment—especially if caught in childhood.

Don't live with a bite problem that's affecting your comfort, appearance, or oral health. Modern orthodontics has excellent solutions.