Abstract: Taurodontism is a rare tooth deformity,a change in tooth shape caused by the failure of Hertwig’s epithelial sheath diaphragm to invaginate at the proper horizontal level，However, its pathogenesis is not fully understood.An enlarged pulp chamber,apical displacement of the pulpal floor and bifurcation or trifurcation of the root， and no constriction at the level of the cemento-enamel junction are the characteristic features.Although permanent molar teeth are most commonly affected, this change can also be seen in both the permanent and deciduous dentition,unilaterally or bilaterally,and in any combination of teeth or quadrants. Whilst it appears most frequently as an isolatedanomaly, its association with several syndromes has also been reported. Usually no obvious clinical symptoms, most of the X-ray film to be found.This article summarizes the etiology, clinical and radiological features of the taurodontism, the relationship between the various syndromes, and the dental treatment of such teeth to meet the urgent need for diagnosis and treatment.

Key words: taurodontism, tooth deformity, enlarge pulp chamber, Tanurodontic Index, root canal therapy