Healing after Root-end Microsurgery by Using Mineral Trioxide Aggregate and a New Calcium Silicate-based Bioceramic Material as Root-end Filling Materials in Dogs

Introduction: The purpose of this study was to compare healing after root-end surgery by using grey mineral trioxide aggregate (MTA) and EndoSequence Root Repair Material (RRM) as root-end filling material in an animal model. Methods: Apical periodontitis was induced in 55 mandibular premolars of 4 healthy beagle dogs. After 6 weeks, root-end surgeries were performed by using modern microsurgical techniques. Two different root-nd filling materials were used, grey MTA and RRM. Six months after surgery, healing of the periapical area was assessed by periapical radiographs, cone-beam computed tomography (CBCT), micro computed tomography (CT), and histology. Results: Minimal or no inflammatory response was observed in the majority of periapical areas regardless of the material. The degree of inflammatory infiltration and cortical plate healing were not significantly different between the 2 materials. However, a significantly greater root-end surface area was covered by cementum-like, periodontal ligament like tissue, and bone in RRM group than in MTA group. When evaluating with periapical radiographs, complete healing rate in RRM and MTA groups was 92.6% and 75%, respectively, and the difference was not statistically significant (P = 073). However, on CBCT and micro CT images, RRM group demonstrated significantly superior healing on the resected root-end surface and in the periapical area (P = 000 to .027). Conclusions: Like MTA, RRM is a biocompatible material with good sealing ability. However, in this animal model RRM achieved a better tissue healing response adjacent to the resected root-end surface histologically. The superior healing tendency associated with RRM could be detected by CBCT and micro CT but not periapical radiography.