4Wolcott J, Ishley D, et al. Clinical investigation of second mesiobuccal canal in endodontically treated and retreated maxillary molars. J Endod, 2002,28(6):477 - 479.
5Stropko JJ. Canal morphology of maxillary molars: clinical observations of canal configurations. J Endod, 1999, 25 (6) : 446 -450.
6Waslton RE,Torabinejad M. Principles and practice of endodontics [ M ] : 3rd ed, Saunders Phitadepbia, 2002.74.
7Schneider SW. A comparison of canal preparation in straight and cured root canal [ J ]. J Oral Surg, 1971 , 32 ( 3 ) : 271 - 275.
8Gulabivala K, Opasanon A, Ng YL, et al. Root and canal morphology of Thai mandibular molars. Int Endod J, 2002, 35(1):56-62.
9Loh HS. Root morphology of the maxillary first premolar in Singaporeans. Aust Dent J, 1998, 43(6): 399-402.
10Chaparro AJ, Segura JJ, Guerrero E, et al. Number of roots and canals in maxillary first premolars: study of an Andalusian population. Endod Dent Traumatol, 1999, 15(2): 65-67.
