title: Setting time and thermal expansion of two endodontic cements.
abstract: The purpose of this study was to evaluate the setting time and the thermal expansion coefficient of 2 endodontic cements, MTA-Angelus and a novel cement called CER. The setting time was determined in accordance to ANSI/ADA specifications no. 57. Three samples of 10 mm diameter and 2 mm thickness were prepared for each cement. The thermal expansion measurements were performed by strain gauge technique. Four samples of each cement were prepared using silicone rings of 5 mm diameter and 2 mm thickness. The data were analyzed statistically using the Student t test. The setting time obtained for the MTA-Angelus and CER cements was 15 (SD 1) min and 7 (SD 1) min, respectively. The linear coefficient of thermal expansion was 8.86 (SD 0.28) microstrain/ degrees C for MTA-Angelus and 11.76 (SD 1.20) microstrain/ degrees C for CER. The statistical analysis showed significant difference (P < .05) in the setting time and linear coefficient of thermal expansion between the 2 cements. The CER cement has a coefficient of expansion similar to dentin, which could contribute to a decrease of microleakage degree.
authors.affiliation: Department of Physics and Chemistry, Ilha Solteira, Brazil.
authors.forename: Alailson D
authors.initials: AD
authors.lastname: Santos
authors.forename: Eudes B
authors.initials: EB
authors.lastname: Araújo
authors.forename: Keizo
authors.initials: K
authors.lastname: Yukimitu
authors.forename: José C
authors.initials: JC
authors.lastname: Barbosa
authors.forename: João C S
authors.initials: JC
authors.lastname: Moraes
mesh_terms: D001466:Barium Sulfate; D001729:Bismuth; D002118:Calcium / Q000032:analysis; D003738:Dental Cements; D003799:Dental Stress Analysis; D006358:Hot Temperature; D006878:Hydroxides / Q000032:analysis; D008422:Materials Testing; D010087:Oxides; D012387:Root Canal Filling Materials / Q000737:chemistry; D017640:Silicates; D013997:Time Factors
chemical_list: D003738:Dental Cements; D006878:Hydroxides; C475480:MTA-Angelus; D010087:Oxides; D012387:Root Canal Filling Materials; D017640:Silicates; C472247:accelerated Portland cement; D001466:Barium Sulfate; C031356:hydroxide ion; D002118:Calcium; D001729:Bismuth