title: Retreatability of 2 mineral trioxide aggregate-based root canal sealers: a cone-beam computed tomography analysis.
abstract: BACKGROUND
  The retreatability of recent calcium silicate or mineral trioxide aggregate (MTA) sealers has not yet been assessed. The aim of this study was to evaluate the removal of 2 MTA-based sealers (MTA Fillapex [Angelus Soluções Odontológicas, Londrina, PR, Brazil] and MTA Plus [Prevest-Denpro, Jammu City, India]) using a rotary retreatment system, considering an epoxy resin sealer (AH Plus [Dentsply Maillefer, Ballaigues, Switzerland]) as the standard for comparison.
  
  
  METHODS
  Root canals in 45 single-rooted teeth were instrumented using a rotary nickel-titanium system (MTwo; VDW GmbH, Munich, Germany) and obturated with gutta-percha using one of the following sealers (n = 15): group 1, MTA Fillapex; group 2, MTA Plus; and group 3, AH Plus. The teeth were scanned using a cone-beam computed tomography scanner. After 2 months, the root canals were retreated with a rotary retreatment system (ProTaper Universal Retreatment; Dentsply Maillefer, Ballaigues, Switzerland) and a second cone-beam computed tomography scan was performed to assess the amount of remaining root filling material (in percentage) and dentin removal (in cubic millimeters). The time taken to reach the working length was calculated in minutes. Group comparisons were performed using 1-way analysis of variance and the Student-Newman-Keuls post hoc test (P = .05).
  
  
  RESULTS
  There was a significant difference in the amount of remaining root filling material between the 3 groups (P < .05), with group 1 showing the least amount of root filling material (1.8% ± 0.22%) and group 3 showing the highest (10.4% ± 0.71%). The amount of dentin removal and the time taken to reach the working length was significantly higher in group 3 than in groups 1 and 2 (P < .05). There was no significant difference between groups 1 and 2 in these outcome variables (P > .05).
  
  
  CONCLUSIONS
  The rotary retreatment system evaluated was not able to completely remove any of the sealers. MTA Fillapex showed less remaining root filling material than MTA Plus.
authors.affiliation: Department of Conservative Dentistry and Endodontics, Saveetha Dental College and Hospitals, Saveetha University, Chennai, India. prasanna_neelakantan@yahoo.com
authors.forename: Prasanna
authors.initials: P
authors.lastname: Neelakantan
authors.forename: Deeksha
authors.initials: D
authors.lastname: Grotra
authors.forename: Subash
authors.initials: S
authors.lastname: Sharma
mesh_terms: D017607:Aluminum Compounds / Q000737:chemistry*; D019412:Anatomy, Cross-Sectional; D017610:Calcium Compounds / Q000737:chemistry*; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D003786:Dental Pulp Cavity / Q000000981:diagnostic imaging*; D003804:Dentin / Q000000981:diagnostic imaging; D004338:Drug Combinations; D004853:Epoxy Resins / Q000737:chemistry; D006171:Gutta-Percha / Q000737:chemistry; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008422:Materials Testing; D010087:Oxides / Q000737:chemistry*; D019233:Retreatment; D012387:Root Canal Filling Materials / Q000737:chemistry*; D012389:Root Canal Obturation / Q000379:methods; D018915:Root Canal Preparation / Q000295:instrumentation / Q000379:methods*; D017640:Silicates / Q000737:chemistry*; D013499:Surface Properties; D013997:Time Factors
chemical_list: D017607:Aluminum Compounds; D017610:Calcium Compounds; D004338:Drug Combinations; D004853:Epoxy Resins; D010087:Oxides; D012387:Root Canal Filling Materials; D017640:Silicates; C534916:epoxy resin-based root canal sealer; C086631:mineral trioxide aggregate; D006171:Gutta-Percha