title: Evaluation of physicochemical properties of four root canal sealers.
abstract: OBJECTIVE
  To assess the physicochemical properties and the surface morphology of AH Plus, GuttaFlow, RoekoSeal and Activ GP root canal sealers.
  
  
  METHODS
  Five samples of each material were evaluated for setting time, dimensional alteration, solubility and radiopacity tests, according to ANSI/ADA Specification 57. A total of 50 mL of deionized distilled water from the solubility tests were used to measure the metal solubility by atomic absorption spectrometry. The morphologies of the external surface and the cross-section of the samples were analysed by means of a scanning electron microscope (SEM). Statistical analysis was performed by using one-way anova and post hoc Tukey-Kramer tests with the null hypothesis set as 5%.
  
  
  RESULTS
  AH Plus had the longest setting time (580.6 ± 3.05 min) (P<0.05). Activ GP did not have a mean value on the radiopacity and solubility tests (1.31 ± 0.35 mm and 11.8 ± 0.43%, respectively) in accordance with ANSI/ADA, being significantly different from the other materials (P<0.05), which had mean values for these tests in accordance with the ADA's requirements. GuttaFlow was the only sealer that conformed to the Specification 57 concerning the dimensional alteration test (0.44 ± 0.16%) (P<0.05). The spectrometry test revealed significant Ca(2+), K(+), Zn(2+) ion release from Activ GP sealer (32.57 ± 5.0, 1.57 ± 0.22 and 8.20 ± 1.74 μg mL(-1), respectively). In SEM analysis, the loss of matrix was evident and the filler particles were more distinguishable in all groups.
  
  
  CONCLUSIONS
  The setting time of all sealers was in accordance with ANSI/ADA's requirements. Activ GP did not fulfill ANSI/ADA's protocols regarding radiopacity, dimensional alteration and solubility. GuttaFlow was the only sealer that conformed to the Specification 57 in all tests. SEM analysis revealed that the surfaces of all sealers had micromorphological changes after the solubility test.
authors.affiliation: Department of Restorative Dentistry, Faculty of Dentistry of Ribeirão Preto, University of São Paulo (FORP-USP), Ribeirão Preto, SP, Brazil.
authors.forename: D S H
authors.initials: DS
authors.lastname: Flores
authors.forename: F J A
authors.initials: FJ
authors.lastname: Rached
authors.forename: M A
authors.initials: MA
authors.lastname: Versiani
authors.forename: D F C
authors.initials: DF
authors.lastname: Guedes
authors.forename: M D
authors.initials: MD
authors.lastname: Sousa-Neto
authors.forename: J D
authors.initials: JD
authors.lastname: Pécora
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000571:American Dental Association; D000704:Analysis of Variance; D055598:Chemical Phenomena; D003738:Dental Cements / Q000737:chemistry; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D004338:Drug Combinations; D004708:Endodontics / Q000592:standards*; D004853:Epoxy Resins / Q000737:chemistry; D006171:Gutta-Percha / Q000737:chemistry; D008422:Materials Testing; D012387:Root Canal Filling Materials / Q000737:chemistry* / Q000592:standards; D012995:Solubility; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013997:Time Factors; D014481:United States
chemical_list: D000180:Acrylic Resins; D003738:Dental Cements; D004129:Dimethylpolysiloxanes; D004338:Drug Combinations; D004853:Epoxy Resins; C515718:GuttaFlow; D012387:Root Canal Filling Materials; C528807:activ GP sealer; C534916:epoxy resin-based root canal sealer; C465381:roeko seal; D006171:Gutta-Percha