Because Angle is a proper name, it is spelled with a capital A. a system for classifying different types of malocclusion, based on the mesiodistal relationship of the permanent molars on their eruption and locking, and consisting of three classes; Class I: normal relationship of the jaws, wherein the mesiobuccal cusp of the maxillary first molar occludes in the buccal groove of the mandibular first permanent molar; Class II: distal relationship of the mandible, wherein the distobuccal cusp of the maxillary first permanent molar occludes in the buccal groove of the mandibular first molar, and further classified as Division 1, labioversion of maxillary incisor teeth, and Division 2, linguoversion of maxillary central incisors, both of which may be unilateral conditions; Class III: mesial relationship of the mandible, wherein the mesiobuccal cusp of the maxillary first molar occludes in the embrasure between the mandibular first and second permanent molars, further classified as a unilateral condition.