Chronic habitual chewers usually present with a lack of passive laterotrusive range of mandibular motion at maximum intercuspation, and many have some form of mandibular asymmetry. This study attempted to discover mechanisms that may be responsible for this association and proposes a system by which such persons can be classified based on physiognomy and patterns of mandibular deviation. The influence of facial biotype and altered head posture on the selection of a preferred chewing side was also analyzed.