Malocclusion refers to the misalignment of the upper and lower dental arches when the jaws occlude, resulting in an improper contact relationship between opposing teeth. Derived from the Latin malus (bad) and occludere (to close), the term covers a broad spectrum of bite irregularities affecting both oral function and facial aesthetics.

Classification

The most widely used framework is Angle’s classification system, which categorizes malocclusion based on the molar relationship between arches:

• Class I: Normal molar relationship, but with localized crowding, spacing, or individual tooth rotations
• Class II (Overbite/Overjet): The upper arch protrudes relative to the lower, commonly described as excessive overjet or “buck teeth”
• Class III (Underbite): The lower jaw extends forward, positioning the lower teeth anterior to the upper teeth

Additional variations — crossbite, open bite, and deep bite — describe more specific spatial relationships between opposing arches and are often documented alongside Angle’s classification.

Common Causes

• Hereditary discrepancies in jaw size or tooth size that affect arch development
• Early loss of primary teeth, disrupting normal permanent tooth eruption paths
• Prolonged thumb-sucking or pacifier use during critical growth windows
• Chronic mouth breathing, which can alter palatal and jaw development over time
• Oral trauma or poorly contoured restorations that shift the occlusal plane

Clinical Significance

The consequences of untreated malocclusion extend well beyond appearance. Uneven occlusal forces accelerate enamel wear and increase the risk of cusp fractures or cracked restorations. Severe misalignment places chronic stress on the temporomandibular joint (TMJ), contributing to jaw pain, limited opening, and referred headaches. Crowded or overlapping teeth also compromise plaque removal, elevating susceptibility to periodontal disease and interproximal caries.

Diagnosis relies on clinical examination, dental models or intraoral scans, and cephalometric radiographs that quantify both skeletal and dental relationships to guide treatment planning.

Treatment Options

Management is tailored to severity, the patient’s age, and the underlying cause:

• Fixed appliances (braces) or clear aligners to move teeth into proper alignment
• Functional or orthopedic appliances to redirect jaw growth in growing patients
• Strategic extraction to resolve arch-length discrepancies before orthodontic movement
• Orthognathic surgery combined with orthodontics for significant skeletal malocclusions in adults

Identifying malocclusion early — orthodontic guidelines recommend an initial evaluation by age seven — enables interceptive treatment that can reduce complexity, shorten active treatment time, and protect both dental and joint health over the long term.