Root canal obturation by ultrasonic condensation of gutta-percha. Part II: an in vitro investigation of the quality of obturation

AIM: To compare the quality of root canal obturation using ultrasonic or cold condensation of gutta-percha and to determine the effect of power setting and activation time on the quality of obturation using the former technique. METHODOLOGY: An extracted human maxillary canine was used in an in vitro split tooth model to allow repeated obturation of the same root canal system using an ultrasonic device to thermocompact gutta-percha without sealer. After each obturation, the root filling was removed from the tooth to allow evaluation of its quality and for the tooth to be re-obturated. The influence of combinations (n = 10 per combination) of power setting (1, 3, 5) and activation times (4, 10, 15 s) was tested on the quality of root filling, assessed by measuring the voids within the body of the root filling as well as at the surface. Image analysis was used to quantify the voids within the body of the root filling. Cold lateral condensation of gutta-percha served as a control. RESULTS: Both surface and cross-sectional analyses revealed that different power setting and activation time combinations produced significantly fewer voids than cold lateral condensation (P < 0.05) at the apical, mid-root and coronal levels. CONCLUSIONS: Taking surface and cross-sectional analysis together only power setting 5 and activation times of 10 and 15 s consistently produced ultrasonically thermocompacted root canal fillings with fewer voids than cold lateral condensation without sealer.