Negative influence of continuous wave technique on apical sealing of the root canal system with Resilon

The aim of this study was to investigate apical microleakage after use of the Resilon system in comparison with gutta-percha. The materials used were 54 mesial roots of mandibular molars with an apical curvature of 20-40 degrees . The root canals were instrumented with the Prosystem GT(R) and obturated with: Group I: Gutta-percha + Sealer by lateral condensation (n = 25); Group II: Gutta-percha + Sealer, complemented by System B and Obtura II (n = 25); Group III: Resilon + System B and Obtura II (n = 25); Group IV: Resilon by lateral condensation (n = 25). After immersion in India ink, the specimens were demineralized and rendered transparent. Apical dye leakage was analyzed with a stereomicroscope and a digital camera connected to a computerized system. All groups showed different degrees of apical dye microleakage. The Kruskal-Wallis test revealed that the largest leakage occurred in Group I (P < 0.05), whereas the other groups presented a similar pattern of microleakage (P > 0.05). Thermoplastification negatively influenced the apical sealing ability of Resilon. Gutta-percha points and conventional sealer yielded the highest values of apical leakage, especially when the lateral condensation technique was used. Regardless of the obturation technique employed, the Resilon system provided the lowest mean values of apical leakage, but did not provide hermetic sealing of the root canal system.