Introduction: new materials and techniques were developed to achieve adequate root canal obturation by complete filling of the canal space with a stable, biocompatible material that prevents the ingress of bacteria and/or its by-products to periapical tissue. The purpose of this study was to evaluate quality of two different root canal sealer and filling techniques using cone beam computerized tomography (CBCT) Materials and methods: Seventy-two root canals were prepared using protaper next rotary system. Root canals were divided into two equal groups 36 teeth each. Group I: teeth were obturated using single cone technique with MTA fill apex sealer. Group II: teeth were obturated using continuous wave technique with resin-based sealer (AH plus). The voids within filling materials as well as along dentin walls were examined using CBCT. Result: results revealed that the difference between different thirds was extremely statistically significant in single cone technique, while in continuous wave technique there was no significant difference between thirds. There was no significant difference between both techniques in apical and middle third, while in cervical third there was a significant difference, as single cone showed more voids. Both techniques showed accepted working length of the obturation. Conclusions: CBCT is an accurate tool for assessment of root canal filling quality. There were more voids present in coronal third in both techniques. Continuous wave technique showed fewer voids in cervical third compared to single cone technique. The present study showed that none of the root canal obturated teeth were gap-free.