The quality of root canal filling in mandibular molars utilizing warm vertical and single cone technique : a three-dimensional micro-computed tomography

The goal of the root canal filling procedure is the total 3-dimensional filling of root canals and accessory canals. With the development of innovative sealers and gutta percha in matching taper and diameter as rotary instruments, the single cone technique is gaining popularity. Objective: To compare the percentage of voids and gaps in the coronal, middle and apical third of mandibular molar root canals obturated with different sealers and techniques using micro-computed tomography. Hypothesis: No differences in the percentage of voids and gaps are found between: 1) the obturation groups; 2) the mesial or distal canals of the mandibular molars; and 3) the root canal thirds. Methods: Thirty extracted two-rooted human mandibular molars were divided into three experimental groups: 1) single cone technique using ThermaSeal Plus sealer; 2) warm vertical technique using ThermaSeal Plus sealer; and 3) single cone technique using BC sealer. All canals were instrumented with Vortex Blue 0.04 files to an apical size of #35 (mesial) and #40 (distal). The teeth were mounted on a custom attachment for post-instrumentation and post-obturation micro-CT scan. The scans were examined for the relative proportions of voids and gaps in the coronal, middle and apical third of mandibular molar root canals. Data were analyzed with mixed effects models and Wald chi-square test. Results: A statistically higher percentage of gaps was found in the apical third compared to the coronal third and the middle third of the canal (p 0.05). None of the methods were able to produce a void-free root filling and voids occurred in both mesial and distal canals with no predilection for any part of the canals. Conclusion: Within the limitations of this study, it appears that the single cone technique utilizing gutta percha in matching taper and size as rotary instruments is a suitable alternative for obturation of mandibular molars as compared to the warm vertical technique.Dentistry, Faculty ofGraduat