RESUMO
This study compared the incidence of incomplete root fractures among five groups of mandibular incisors (20/group). The groups were: (a) no canal preparation, (b) canal preparation, (c) canal preparation and obturation with laterally condensed gutta-percha, (d) canal preparation and obturation with thermoplasticized gutta-percha on a central carrier (Thermafil), and (e) canal preparation and obturation with thermoplasticized injectable gutta-percha (Ultrafil). Following experimental manipulation, all teeth were stained, transversely sectioned, and evaluated for the presence of root fracture. No complete root fractures were noted. The lowest incidence of stained incomplete fracture was found in the no canal preparation group. The canal preparation, lateral condensation, Ultrafil, and Thermafil groups had more incomplete fractures than the no canal preparation group. The incidence of stained fracture in the three obturation groups was not significantly different from the incidence in the group which had only canal preparation.
