Resistance to Fracture of Roots Obturated with Novel Canal-filling Systems

Introduction: This study was conducted to evaluate and compare the fracture resistance of roots obturated with various contemporary canal-filling systems. Methods: Fifty single-rooted extracted mandibular premolars were decoronated to obtain 13-mm root segments. Ten roots were left unprepared and unfilled (negative control). Forty canals were instrumented using 0.06 taper Endo Sequence files (Brassier, Savannah, GA). Roots were divided according to the obturating system into 4 groups (n = 10): group 1: iRoot SP sealer (Innovative Bioceramix, Vancouver, Canada) + ActiV GP cone (Brasseler USA, Savanah, GA), group 2: iRoot SP sealer + gutta-percha (GP), group 3: ActiV GP sealer + ActiV GP cone, and group 4: ActiV GP sealer + GP. All groups were obturated using single-cone technique. The roots within each group were embedded in acrylic molds and subjected to the fracture resistance test in which a compressive loading (0.5 mm/min) was applied until fracture. Data were statistically analyzed (analysis of variance and Tukey post hoc test). Results: The significantly highest fracture resistance was recorded for both the negative control group (381.4 +/- 53.2 N) and group 1 (iRoot SP sealer/ActiV GP cone [372 +/- 62.9 N]) with no significant difference between them, whereas the significantly lowest value was reported in group 4 (ActiV GP sealer/GP cone [288.3 +/- 30.5 N]). Conclusion: Bioceramic-based sealer (ie, iRoot SP) is a promising sealer in terms of increasing in vitro resistance to the fracture of endodontically treated roots particularly when accompanied with ActiV GP cones. (J Endod 2011;37:1590-1592)