The objective of this study was to evaluate and compare the filling ability of various
root canal obturation techniques on the internal
root resorption (
IRR) cavities of replicated tooth samples manufactured using computer software and a three-dimensional (3D) printer. Orthographic images and root structures of a healthy upper maxilla central incisor in determined volumes and sizes were drawn as a prototype with the aid of computer software. Using the same software, an
IRR defect was also modeled. These two images were then transferred to the AutoDesk Fusion 360 3D modeling program (AutoDesk, San Rafael, CA) for meshing. Afterward, the tooth model was transferred to a 3D modeling and prototyping program (RhinoCeros 3D; Robert McNells & Assoc., New York) and printed on a 3D printer. Eighty replicas with
IRR were manufactured and divided into four groups (n = 20 per group) according to the obturating techniques as follows: Group 1: Cold lateral compaction (CLC), Group 2: Core Carrier System (GuttaCore), Group 3:
Injectable Cold Filling (GuttaFlow®
BioSeal), and Group 4: Continuous Wave Obturation System (Elements Free). After root canal filling, replicas were scanned with a high-resolution micro-computed tomography system (SkyScan 1172; Bruker-microCT, Kontich, Belgium), data regarding voids (unobturated areas) inside the
IRR defects were statistically analyzed using nonparametric Kruskal-Wallis tests. A pairwise comparison between the tested groups showed that Groups 3 and 4 had significantly fewer voids compared with Groups 1 and 2 in
IRR defects (p < 0.05). Group 1/Group 2 and Group 3/Group 4 had similar results in terms of voids and there were no statistically significant differences (p > 0.05). The
injectable cold filling system (
GuttaFlow BioSeal) and the
injectable continuous wave obturation system (Elements Free) successfully obturated the pathological
IRR irregularities when compared with CLC and core carrier (GuttaCore) systems.