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

"Objectives:" This study was conducted to compare fracture resistance of roots obturated with various canal-filling systems and to evaluate it's adaptation to canal walls. "Methods:" Fifty-eight single rooted extracted mandibular premolars were decoronated to obtain 13mm root segments. Ten roots were left unprepared and unfilled (control group). Forty-eight canals were instrumented using EndoSequence files. Following instrumentation, roots were randomly divided according to the obturating system into four groups (n=12); group 1: iRoot SP sealer + ActiV GP cone, 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. Two samples from each group were prepared for interfacial scanning electron microscopic examination. The remaining 10 roots within each group were embedded in acrylic moulds and subjected to fracture resistance test where a compressive loading (0.5mm/min) was applied till fracture. Data were statistically analyzed (ANOVA, Tukey's post-hoc test). "Results:" Among the experimental groups, a statistically significant difference was noted in the fracture resistance values (P≤0.05). The highest fracture resistance value was recorded for group 1; iRoot SP sealer/ActiV GP cone (372±62.9N), while the lowest value was reported in group 4; ActiV GP sealer/GP cone (288.3±30.5N). The control group recorded a significantly higher fracture resistance than the other experimental groups except for group 1 where no significance was found (P>0.05). Furthermore, intimate contact and excellent sealer adaptation along the length of the canal walls was observed in groups 1 and 2, unlike groups 3 and 4 where gaps and voids were observed. "Conclusion:" Bioceramic-based sealer, iRoot SP, is a promising sealer in terms of increasing in-vitro resistance to fracture of endodontically treated roots and adaptation to canal walls particularly when accompanied with ActiV GP cones.