What Is Malocclusion?
Malocclusion is a misalignment between the upper and lower teeth or jaws that prevents them from meeting properly when you close your mouth. The word means "bad bite," and it covers a wide range of issues, from a few crowded front teeth to skeletal differences that affect facial balance.
Orthodontists classify malocclusion using a system developed by Edward Angle. Class I means the back teeth fit normally but front teeth may be crowded or spaced. Class II is an overbite, where the upper jaw or upper teeth sit too far forward. Class III is an underbite, where the lower jaw extends past the upper one. Each class can also include rotations, crossbites, open bites, or deep bites.
Malocclusion traits are common across populations. A systematic review of global epidemiology found that Class I patterns are most prevalent overall, with Class II and Class III, crowding, and deep bites also reported at meaningful rates worldwide.[7] Mild misalignment is often cosmetic, but moderate to severe cases can affect chewing, speech, jaw comfort, and long-term tooth wear.
Causes and Risk Factors
Malocclusion develops from a mix of inherited jaw and tooth size, oral habits during childhood, and disruptions to normal dental development. Most cases involve more than one factor working together over time.
Genetic and Skeletal Factors
Jaw size, tooth size, and facial growth patterns are largely inherited. When a child inherits a small jaw from one parent and large teeth from another, crowding is likely. Skeletal Class II and Class III patterns also tend to run in families, since the size and position of the upper and lower jaws are genetically influenced.[1]
Oral Habits in Childhood
Prolonged non-nutritive sucking habits, such as thumb sucking or extended pacifier use, are well-documented contributors to malocclusion. A 2024 systematic review found these habits increase the risk of anterior open bite, posterior crossbite, and increased overjet, with risk rising the longer the habit continues past age three.[3]
Atypical swallowing patterns, sometimes called tongue thrust, push the tongue against or between the front teeth during swallowing. A 2024 systematic review reported associations between atypical swallowing and open bite, increased overjet, and other malocclusions, and noted that orthodontic treatment combined with myofunctional therapy can help correct both the bite and the swallowing pattern.[2]
Mouth breathing, often linked to enlarged adenoids, allergies, or nasal obstruction, is another risk factor. Research has associated chronic mouth breathing with narrower upper arches, open bites, and Class II tendencies.[9]
Dental Development Issues
Premature loss of primary (baby) teeth can shift the path of permanent teeth and reduce space for them to erupt. A 2023 systematic review and meta-analysis concluded that early loss of primary teeth is associated with a higher prevalence of malocclusion in the permanent dentition, including crowding and midline deviation.[4]
Other dental factors include extra teeth, missing teeth, impacted teeth, and trauma that displaces teeth or affects jaw growth. Cleft lip and palate and certain syndromes also produce specific malocclusion patterns that need coordinated specialist care.[1]
Symptoms and Diagnosis
Symptoms range from purely cosmetic concerns to functional problems. Diagnosis combines a clinical exam, photos, dental impressions or digital scans, and X-rays to evaluate both teeth and jaw structure.
What Patients Notice
Common signs include crooked or crowded teeth, gaps, an upper jaw that protrudes, a lower jaw that sits forward of the upper, front teeth that do not touch when biting, or back teeth that bite on the outside instead of the inside. Some patients notice difficulty chewing certain foods, biting the inside of the cheek, uneven tooth wear, or trouble pronouncing certain sounds.
Severe malocclusion can also contribute to jaw muscle fatigue, headaches, and snoring or sleep-disordered breathing in some patients. Because severe bite problems can affect chewing efficiency and oral function, a comprehensive pediatric assessment is important when symptoms are significant.
How Orthodontists Diagnose Malocclusion
An orthodontic evaluation typically includes a medical and dental history, a clinical exam of teeth, gums, and jaw joints, and records such as photos, digital scans or impressions, and X-rays. A panoramic X-ray shows all teeth and jaws, while a cephalometric (side-profile) X-ray measures jaw position and angles.
From these records, the orthodontist assigns an Angle classification, measures overjet and overbite, and identifies crowding, spacing, crossbites, and open bites. They also assess facial growth, airway, and habits. The American Association of Orthodontists recommends a first orthodontic check by age 7, when mixed dentition allows early detection of skeletal and developmental issues.[10]
Treatment Options
Treatment depends on the type and severity of malocclusion, the patient's age, and whether the problem is dental, skeletal, or both. Options range from observation and growth-guidance appliances in children to braces, clear aligners, and orthognathic surgery for adults with skeletal differences.
Early and Interceptive Treatment
In children, early treatment can address habits and guide jaw growth before adolescence. Habit appliances, palatal expanders, and partial braces are common tools. A 2024 expert consensus on pediatric orthodontic therapies outlines age-appropriate strategies for crossbites, Class II and Class III patterns, and habit-driven malocclusions.[1]
For Class III (underbite) tendencies, a systematic review and meta-analysis found that early orthopedic treatment, often using a facemask with maxillary expansion, produced favorable short-term changes in jaw relationships compared with no treatment, though long-term stability varies.[8] Early treatment does not always avoid later braces, but it can simplify a second phase or reduce the need for surgery.
Braces and Clear Aligners
Fixed braces remain the standard for moving teeth precisely, especially in complex cases involving rotations, severe crowding, or significant bite correction. Clear aligners are removable trays that move teeth in small increments and have grown rapidly in popularity for mild to moderate cases.
A 2020 systematic review with meta-analyses compared aligners and fixed appliances and found that fixed braces achieved better outcomes overall, particularly for complex tooth movements and bite correction. Aligners performed reasonably for simpler alignment, but treatment was often less predictable when significant occlusal changes were needed.[6] Choosing between them depends on the bite problem, patient compliance, and goals discussed with your orthodontist.
Orthognathic Surgery for Skeletal Cases
When the upper and lower jaws are significantly mismatched in size or position, braces alone may not fix the bite. Orthognathic (jaw) surgery repositions the jaws, usually combined with orthodontic treatment before and after surgery.
For borderline Class III cases, patients often face a choice between orthodontic camouflage (moving teeth to mask the skeletal difference) and combined orthodontic-surgical treatment. A 2022 systematic review found that surgical treatment produced greater skeletal correction and facial profile change, while camouflage offered shorter treatment and avoided surgery, with each approach suited to different severity levels and patient preferences.[5]
Severe Class II skeletal cases, large open bites, and significant facial asymmetries are also common indications for surgery. The decision is highly individualized and made jointly with an oral and maxillofacial surgeon.
Treatment Timeline and Aftercare
Most orthodontic treatment takes 12 to 30 months, followed by long-term retainer wear to keep teeth stable. Surgical cases involve added recovery from the procedure itself.
During active treatment, patients typically see the orthodontist every 4 to 10 weeks for adjustments or new aligner sets. Soreness for a few days after each visit is common. Good oral hygiene is critical, since brackets, wires, and aligner attachments make plaque control harder. The American Dental Association provides guidance on brushing and flossing techniques during orthodontic care.[11]
After active treatment ends, retainers are essential. Teeth naturally tend to shift over time, and bite correction is not permanent without retention. Orthodontists usually prescribe full-time retainer wear for several months, then nighttime wear long term. For surgical patients, recovery from orthognathic surgery generally includes several weeks of swelling and a soft or liquid diet, followed by months of final orthodontic refinement to settle the bite.
Cost and Insurance Considerations
Orthodontic treatment for malocclusion typically ranges from a few thousand dollars for simple alignment to substantially more for complex or surgical cases. Costs vary by location, provider, and case complexity.
Factors that influence cost include appliance type (traditional braces, ceramic braces, lingual braces, or clear aligners), case complexity, treatment length, and whether early-phase treatment, expanders, or surgery are needed. Adult treatment is generally similar in cost to adolescent treatment for comparable cases, though some adult cases are more complex.
Insurance often covers a portion of orthodontic care, especially for children, when treatment is judged medically necessary or when a plan includes a specific orthodontic benefit. Lifetime maximums and age limits are common. Many practices offer in-house payment plans, and Health Savings Accounts (HSAs) and Flexible Spending Accounts (FSAs) can be used for qualified orthodontic expenses.
When to See an Orthodontist
An orthodontist is a dentist with two to three additional years of specialty training in tooth movement and jaw development. While general dentists can identify malocclusion and offer some alignment options, an orthodontist focuses exclusively on diagnosing and correcting bite problems.
Consider an orthodontic consultation if you notice crowding, spacing, an obvious overbite or underbite, jaw shifting when biting, breathing or speech concerns, or if a general dentist recommends evaluation. For children, the American Association of Orthodontists recommends a first orthodontic visit by age 7, even if no problem is obvious, since some issues are easier to address while jaws are still growing.[10]
Complex skeletal malocclusions, surgical cases, and atypical swallowing or airway-related bite problems benefit most from specialist care, often coordinated with oral surgeons, ENT physicians, or speech and myofunctional therapists.[2]
Find an Orthodontist Near You
If you or your child has signs of a bite problem, a consultation with an orthodontist can clarify what is happening and what options exist. Visit the orthodontics page to learn more about the specialty and find a board-certified orthodontist who can evaluate your bite and walk through treatment options suited to your case.
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