The objective of the present study was to compare the change in temperature on the external surface of the root in vitro during post and core preparation using 4 different techniques. Forty lower single-root premolars instrumented and filled with gutta-percha and stored in 10% formalin were divided into 4 groups according to the technique of gutta-percha removal employed, using heated endodontic pluggers and Peeso, Largo and Gates-Glidden burs. The experiment was performed in a chamber with controlled temperature maintained at about 26°C. For gutta-percha removal from the canals, 2/3 of the root length was calculated and approximately 4 mm of apical filling was left. The temperature of the external surface of the root was measured with a thermo-couple connected to a multimeter and measurements were made in 3 regions: cervical (about 3 mm below the cementum-enamel junction), middle and apical regions of a predetermined measurent. Analysis of variance indicated significant differences (p < 0.01) between regions and techniques. The complementary Tukey test indicated that the heated endodontic pluggers produced the greatest increased in temperature among the three techniques, and the Peeso bur produced the greatest increase in temperature among the burs used. Among regions, the apical one presented the greatest change in temperature for all the techniques evaluated.
Post and core technique; Temperature changes; Root canal preparation; Adverses effects
