Dentinal Microcrack Formation after Root Canal Filling with Thermoplasticized Gutta-percha: an in vitro Study

The objective of the present study was to evaluate the formation of microcracks after root canal filling with thermoplasticized gutta-percha. Thirty freshly extracted mandibular premolars were selected and evenly distributed into three groups (n=10): negative control, BT-Race (positive control), GuttaCore. Roots in the negative control group were left unprepared. After shaping and filling of the root canals, all teeth were horizontally sectioned at 3, 6, 9 mm from the apex and the presence of dentinal defects was registered. These data were analyzed statistically by Fishers exact and chi-square tests (p less than 0.05). No defects were observed in the negative control group. A complete fracture was present in the apical third of one root canal, filled with GuttaCore. In the positive and GuttaCore groups defects at the apical portion of the root canal were higher than those evaluated at the middle and coronal portion but the differences were statistically insignificant.