Micro-CT assessment of hydraulic calcium silicate cements for perforating internal resorption in 3D-printed tooth replicas at different root thirds: An in vitro study

Introduction: Effective repair of perforating internal resorption (PIR) requires adequate defect filling; however, the influence of defect location on the filling ability of hydraulic calcium silicate cements (HCSCs) remains unclear.This micro-computed tomography (micro-CT) study evaluated Bio-C Repair (BCR), Biodentine (BD), and white MTA-Angelus (WMTA) in 3D-printed tooth replicas with PIR defects in different root thirds.The null hypothesis was that material performance would not differ according to defect location.Methodology: A maxillary central incisor was instrumented to size R50 and scanned by micro-CT.PIR defects were digitally created in the apical, middle, and cervical thirds.Ninety replicas were printed and distributed by defect location (n = 30) and HCSC type (n = 10).After obturation, scans quantified cement-filling and extrusion.Surface characteristics were assessed by confocal laser scanning microscopy.Data were analyzed with Welch's ANOVA with Games-Howell post hoc and Kruskal-Wallis tests (p < .05). Results:In apical PIRs, WMTA achieved greater filling and sealing than BCR and BD (p < 0.05), including superior filling of the adjacent apical canal (p < 0.001).No differences were observed in the middle third (p > 0.05).In cervical PIRs, all materials showed high filling, although BD exhibited greater extrusion than WMTA (p < 0.01).BCR presented higher surface roughness in apical PIRs (p < 0.05). Conclusions:HCSC performance in PIR repair was influenced by defect location.WMTA demonstrated more predictable apical adaptation, whereas BD showed greater cervical extrusion under simulated periodontal conditions.