2020 Volume 63 Issue 2 Pages 181-187
Purpose: To compare the obturation ratio in curved root canals filled with a Thermafil obturator (Dentsply Sirona, Tokyo, Japan) or NT condenser (SybronEndo, Orange, CA, USA) with Obturation Gutta NT (Toyo, Tokyo, Japan) using micro-CT analysis.
Methods: Twelve curved root canal models in a Thermafil training block were prepared using the Protaper system, from size S1 to F2. The samples were divided into two groups (n=6 each) for obturation: Thermafil obturator group (TF) and NT condenser with Obturation Gutta NT group (NT). Each canal was prepared to a size of F2 in accordance with the manufacturer’s instructions, and obturated without sealer to prevent artifacts in the micro-CT assessment. Three-dimensional and cross-sectional images along the long axis were obtained at every 1 mm from the apex, up to 8 mm, using the Rigaku microfocus computerized tomography system (Rigaku, Tokyo, Japan). All sectional images were digitally transferred, and the Image J software was used for image analysis. The cross-sectional area of the root canals at distances of 1, 3, and 5 mm from the root apex was used to compare the obturating ratios between groups. These areas were compared statistically at each level using the nonparametric Mann-Whitney U test.
Results: In the TF group, a large amount of softened gutta-percha surrounded the plastic carrier, and the root canal space was completely filled, whereas in the NT group, filling was observed from the coronal surface to the apex, with a few air bubbles. The results of this study suggest that high obturation ratios can be obtained with both the Thermafil obturator (97.5%±1.101) and NT condenser with Obturation Gutta NT (96.4%±2.607) at a distance of 1 mm to 5 mm from the apex. On comparing the obturation ratio between the methods, no significant difference was observed at each point from the apex (p>0.05).
Conclusion: These results indicate that both methods are effective and efficient for routine clinical use, however, using an NT condenser with Obturation Gutter NT does not seem to eliminate the possibility of re-infection due to the presence of air bubbles.
