An evaluation of four methods of root canal preparation using 14C urea

One-hundred twenty single-rooted teeth were used in vitro in order to compare the four following methods of endodontic preparation: manual, Giromatic, MM 3000 Sonic Air with, and sonic air without the contact shaping technique. Each endodontic preparation was filled according to the McSpadden technique. Teeth were immersed in 14C urea. Radioactivity was evaluated qualitatively by autoradiography and quantitatively by scintigraphy. Data were statistically analyzed with a nonparametric test. The results show that the highest degree of leakage occurs with the manual method and that for the three other methods, maximum leakage takes place near the apices.