title: Chemical composition and thermal behavior of five brands of thermoplasticized gutta-percha.
abstract: OBJECTIVE
  The aim of this study was determine the chemical composition and thermal behavior of Thermafil (TH), Microseal Cone (MC), Microseal Microflow (MF), Obtura (OB) and Obtura Flow (OF). In addition, their thermal behavior in response to temperature variations was studied by differential scanning calorimetry (DSC) to determine the temperature at which gutta-percha switches from the beta to alpha form, and from the alpha to the amorphous phase.
  
  
  METHODS
  The organic and inorganic fractions were separated by dissolution in chloroform. Gutta-percha (GP) was precipitated with acetone. The inorganic fraction was analyzed via Elemental Microanalysis. Energy Dispersive X-ray Microanalysis and X-ray Diffraction were used to identify the chemical elements and compounds (BaSO4 and ZnO). Thermal analysis was conducted using DSC.
  
  
  RESULTS
  The organic and inorganic fractions ranged from 21.3% and 26.9% of weights, respectively. MC and MF showed the highest percentages of organic compounds (P = 0.0125). All specimens exhibited two crystalline transformations when heated from ambient temperature to 130°C. MC presented the highest percentage of GP.
  
  
  CONCLUSIONS
  No correlation was observed between chemical composition and thermal behavior. Each of the products showed thermal behavior that is typical of beta-phase gutta-percha.
authors.affiliation: Department of Endodontics, University of Fortaleza (UNIFOR), Fortaleza, Brazil.
authors.forename: Claudio
authors.initials: C
authors.lastname: Maniglia-Ferreira
authors.affiliation: Department of Endodontics, University of Fortaleza (UNIFOR), Fortaleza, Brazil.
authors.forename: Eduardo Diogo
authors.initials: ED
authors.lastname: Gurgel-Filho
authors.affiliation: Department of Organic and Inorganic Chemistry, State University of Ceará (UECE), Fortaleza, CE, Brazil.
authors.forename: João Batista
authors.initials: JB
authors.lastname: de Araújo Silva-Jr
authors.affiliation: Department of Organic and Inorganic Chemistry, Federal University of Ceará (UFC), Fortaleza, CE, Brazil.
authors.forename: Regina Célia Monteiro
authors.initials: RCM
authors.lastname: de Paula
authors.affiliation: Department of Organic and Inorganic Chemistry, Federal University of Ceará (UFC), Fortaleza, CE, Brazil.
authors.forename: Judith Pessoa
authors.initials: JP
authors.lastname: de Andrade Feitosa
authors.affiliation: Department of Endodontics, State University of Campinas (FOP-UNICAMP), Piracicaba, Brazil.
authors.forename: Francisco José
authors.initials: FJ
authors.lastname: de Sousa-Filho
keywords: Chemical composition; gutta-percha; root canal filling materials; thermal behavior; thermoplastic obturation