Original Articles
Marginal Sealing Property of Novel Resin-modified-type MTA Material Using Tri-n-butylborane as a Polymerization Initiator
2020 Volume 63 Issue 1 Pages 52-60
Details
2020 Volume 63 Issue 1 Pages 52-60
Purpose: We have developed a resin-modified-type mineral trioxide aggregate (MTA) material to improve operability and sealing property. The purpose of this study was to evaluate a novel resin-modified MTA material in terms of its sealing property to dentin, and its adhesive property to the resin-based restorative material.
Methods: A novel resin-modified MTA material (PCX-TBB) consisting of white Portland cement, zirconia, hydroxypropyl methacrylate, and partially oxidized tri-n-butylborane (TBBO) as a polymerization initiator, and powder-liquid mix type MTA material (Exp-MTA) were used. The bovine root canal was filled with PCX-TBB or Exp-MTA and stored in simulated body fluid for 10 days. Then the sealing properties of both materials to dentin were evaluated by dye penetration into the interface of dentin and material. In addition, the sealing state of the interface was observed by SEM. Second, PCX-TBB and Exp-MTA were bonded with Super-bond (SB), which is an adhesive resin cement, and the tensile bond strength after storing at 37℃ for 24 hours was evaluated.
Result: In the dye penetration test using bovine root canals, PCX-TBB showed no penetration of dye in all specimens. In seven-tenths of the Exp-MTA specimens, Exp-MTA peeled from the root canal during specimen preparation, and dye penetration occurred in all specimens. SEM observation showed that PCX-TBB and dentin were intimately joined and a large number of tag-like structures had formed in dentinal tubules. The bond strength between PCX-TBB and SB (4.6±2.13 MPa) was significantly higher than that of Exp-MTA and SB (0.9±0.37 MPa). In the comparison of fracture modes, all of the PCX-TBB specimens were fractured inside PCX-TBB, and all of the Exp-MTA specimens were fractured at the interface between Exp-MTA and SB.
Conclusion: PCX-TBB showed a stable sealing property to dentin and had adhesive property to resin-based restorative materials. The present results suggested that PCX-TBB has excellent marginal sealing properties.
