Class III Malocclusion
An Angle classification in which the mesiobuccal cusp of the upper first molar occludes posterior to the buccal groove of the lower first molar, often associated with mandibular protrusion or maxillary deficiency.
Full Definition
Class III malocclusion, as defined in Edward Angle's classification system, occurs when the lower dental arch is positioned anteriorly relative to the upper arch, resulting in the mesiobuccal cusp of the maxillary first molar occluding distal to the buccal groove of the mandibular first molar. It may have a skeletal etiology (mandibular prognathism, maxillary retrusion, or a combination), a dental etiology, or both. The soft-tissue presentation may include a concave facial profile and an anterior crossbite. Editors should use Roman numerals ('Class III,' not 'Class 3') per conventional orthodontic style. The term is frequently paired with subdivision notation when the relationship is asymmetric.
Usage
Usage note: Always use Roman numerals: 'Class III,' not 'Class 3.' Specify whether the etiology is skeletal, dental, or combined.
In Context
- "The patient's Class III malocclusion was attributable to mandibular prognathism requiring combined orthodontic-surgical treatment." — Referral letter
- "The abstract read 'Class 3 malocclusion'; the editor corrected this to 'Class III malocclusion' per orthodontic convention." — Abstract editing