Micro-CT Evaluation of Voids in the Filling Material of Single-Rooted Teeth Obturated with Different Techniques

The aim of this study was to compare the volume of voids in a resin-based root canal filling (Resilon) with gutta percha using either cold lateral condensation or continuous wave of compaction filling techniques using computed X-ray micro-tomography (micro-CT). A total of 56 extracted upper anterior human teeth were decoronated, the canals shaped using rotary ProTaper files to a final size of F3 and randomly allocated into 4 groups (n=14) according to the filling material and obturation technique; Group 1: gutta percha/cold lateral (GP/C), Group 2: Resilon/cold lateral (R/C), Group 3: gutta percha/thermal (GP/T), Group 4: Resilon/thermal (R/T). Thermal filling was performed using System B and Obtura ΙΙ. The filled roots were then scanned using micro-CT and the data were subsequently processed using Avizo 6.3 Standard version software. Statistical analysis was performed using the Kruskal-Wallis test with multiple pairwise comparisons. The total percentage volume of voids in GP/C (2.40%) and R/C (1.88%) were significantly higher than GP/T (1.04%) and R/T (1.29%) (<0.001). A significantly higher percentage of voids was present in the coronal third compared with middle and apical thirds (P<0.001). Thermal obturation resulted in a root filling with significantly fewer voids than the cold lateral condensation technique regardless of the obturation material used. Most of the voids located in the coronal third which emphasizes the importance of obtaining a good coronal seal following endodontic treatment.