title: A new resin-bonded retrograde filling material.
abstract: OBJECTIVE
  This study determined the physical properties and cytotoxicity of a novel root-end filling material (NRC).
  
  
  METHODS
  NRC is a powder and liquid system. The liquid is composed of hydroxyethylmethacrylate, benzoyl peroxide, toluidine, and toluenesulfinate. And the powder is made of calcium oxide, calcium silicate, and triphenylbismuth carbonate. The setting time, compressive strength, and pH change of NRC and gray and white mineral trioxide aggregate (MTA) were determined according to ISO standardization. MC3T3-E1 cells were cultured on NRC and white MTA for determining MTT scores. The absorbance of formazan was measured at 570 nm with a spectrophotometer. The MTT assay was performed in triplicate and repeated in 2 cultures. One-way analysis of variance was used to determine statistical differences in physical properties and MTT assay (P < .05).
  
  
  RESULTS
  Mean setting time of materials tested were: NRC 12.5 +/- 0.3 minutes, gray MTA 345.5 +/- 96.2 minutes, and white MTA 318.0 +/- 56.0 minutes. After 24 hours, the mean compressive strengths were: NRC, 21.6 +/- 5.5 MPa, gray MTA: 7.7 +/- 3.3 MPa, and white MTA, 18.9 +/- 3.2 MPa. The pH of the test materials were: NRC 12.0, gray MTA 12.2, and white MTA 11.9. There were no statistically significant differences in compressive strength and pH between white MTA and NRC. The compressive strength of gray MTA was significantly lower than white MTA and NRC (P < .05). The setting time of NRC was significantly lower than white and gray MTA. In MTT assay, both NRC and white MTA were not cytotoxic to MC3T3-E1 cells.
  
  
  CONCLUSIONS
  It was concluded that the setting time, compressive strength, pH, and initial biocompatibility results of NRC are favorable for a root-end filling material.
authors.affiliation: Department of Conservative Dentistry, Asan Medical Center, Ulsan University, Seoul, Korea.
authors.forename: Miri
authors.initials: M
authors.lastname: Kim
authors.forename: Hyunjung
authors.initials: H
authors.lastname: Ko
authors.forename: Wonkyung
authors.initials: W
authors.lastname: Yang
authors.forename: Youngkyoo
authors.initials: Y
authors.lastname: Lee
authors.forename: Syngcuk
authors.initials: S
authors.lastname: Kim
authors.forename: Francis K
authors.initials: FK
authors.lastname: Mante
mesh_terms: D016475:3T3 Cells / Q000187:drug effects; D017607:Aluminum Compounds / Q000633:toxicity; D000818:Animals; D017610:Calcium Compounds / Q000633:toxicity; D003188:Composite Resins / Q000138:chemical synthesis / Q000737:chemistry / Q000633:toxicity; D019245:Compressive Strength; D003799:Dental Stress Analysis; D004338:Drug Combinations; D005898:Glass; D006863:Hydrogen-Ion Concentration; D051379:Mice; D010087:Oxides / Q000633:toxicity; D012184:Retrograde Obturation; D012387:Root Canal Filling Materials / Q000138:chemical synthesis / Q000737:chemistry / Q000633:toxicity; D017640:Silicates / Q000633:toxicity
chemical_list: D017607:Aluminum Compounds; D017610:Calcium Compounds; D003188:Composite Resins; D004338:Drug Combinations; D010087:Oxides; D012387:Root Canal Filling Materials; D017640:Silicates; C086631:mineral trioxide aggregate