Effect of missing or malposed canine on posterior attrition

Canine is considered nature¿s normal stress breaker. The upper canine,when in functional contacts with the lower canines and first premolars,determine both lateral and protrusive movements of the mandible. Thus, the canine teeth prevent masticatory forces from being applied to the remaining teeth during functional movements of the mandible away from centric occlusion.Another concept claims that the proprioceptors of the periodontal ligament associated with the canine are far more responsive than those of any other teeth. Consequently,the proprioceptors of the canine transmit desirable impulses to the muscles of mastication.Occlusal trauma to the canine teeth is thus prevented by the reduced muscular tension and magnitude of the applied forces.So, Canine acts as a stressbreaker by providing canine guided occlusion. However, in case of missing and malposed canine most of the occlusal forces will be concentrated in posterior teeth thereby providing a group function. Out of them posterior attrition is one of the serious problems. Hence this study was intended to compare the effect of missing or malposed canine on posterior attrition with that of the subjects with normal occlusion.