A
classification of various types of malocclusion, based on the
mesiodistal relationship of the
permanent molars
upon their
eruption and locking, and comprised of
three classes; Class I:
usual 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.