title: Comparative study of white and gray mineral trioxide aggregate (MTA) simulating a one- or two-step apical barrier technique.
abstract: This study investigated the use of Mineral Trioxide Aggregate (MTA) as an apical barrier by comparing the sealing ability and set hardness of white and gray MTA. Forty-four root segments were prepared to simulate an open apex. Apical barriers of white and gray MTA were placed to a thickness of 2 mm or 5 mm. The samples were obturated immediately (one-step) or after the MTA set for 24 h (two-steps). After placement in methylene blue dye for 48 h, the samples were sectioned for leakage analysis and microhardness testing of the barrier. Gray MTA demonstrated significantly less leakage than white MTA (p < 0.001), and the two-step technique showed significantly less leakage than one-step (p < 0.006). The 5-mm thick barrier was significantly harder than the 2 mm barrier, regardless of the type of MTA or number of steps (p < 0.01). Results suggested that a 5 mm apical barrier of gray MTA, using two-steps, provided the best apical barrier.
authors.affiliation: Naval Postgraduate Dental School, Bethesda, MD, USA.
authors.forename: Gary D
authors.initials: GD
authors.lastname: Matt
authors.forename: Jeffery R
authors.initials: JR
authors.lastname: Thorpe
authors.forename: James M
authors.initials: JM
authors.lastname: Strother
authors.forename: Scott B
authors.initials: SB
authors.lastname: McClanahan
mesh_terms: D017607:Aluminum Compounds; D000704:Analysis of Variance; D017610:Calcium Compounds; D003763:Dental Leakage / Q000517:prevention & control*; D004338:Drug Combinations; D006244:Hardness; D006801:Humans; D007180:Incisor; D008422:Materials Testing; D010087:Oxides; D012387:Root Canal Filling Materials; D012389:Root Canal Obturation / Q000379:methods*; D017640:Silicates; D019227:Tooth Apex
chemical_list: D017607:Aluminum Compounds; D017610:Calcium Compounds; D004338:Drug Combinations; D010087:Oxides; D012387:Root Canal Filling Materials; D017640:Silicates; C086631:mineral trioxide aggregate