Brazilian gutta-percha points. Part II: thermal properties.
This study was undertaken to explore the effect of heating on gutta-percha, analyzing the occurrence of endothermic peaks corresponding to the transformation that occurs in the crystalline structure of the polymer during thermal manipulation. This study also sought to determine the temperature at which these peaks occur, causing a transformation from the beta- to the alpha-form, and from the alpha- to the amorphous phase. Eight nonstandardized gutta-percha points commercially available in Brazil (Konne, Tanari, Endopoint, Odous, Dentsply 0.04, Dentsply 0.06, Dentsply TP, Dentsply FM) and pure gutta-percha (control) were analysed using differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA). The transition temperatures were determined and analysed. With the exception of Dentsply 0.04 and Dentsply 0.06, the majority of the products showed thermal behaviour typical of beta-gutta-percha, with two endothermic peaks, exhibiting two crystalline transformations upon heating from ambient temperature to 130 degrees. Upon cooling and reheating, few samples presented two endothermic peaks. It was concluded that heating dental gutta-percha to 130 degrees C causes changes to its chemical structure which permanently alter its physical properties.
Maniglia-Ferreira
Cláudio
C
Department of Endodontics, University of Fortaleza, Rua Bento Albuquerque 685, Papicu, Fortaleza, CE, Brazil, CEP 60190-080. manigliaf@secrel.com.br
Gurgel-Filho
Eduardo Diogo
ED
Silva
João Batista Araújo
JB
Paula
Regina Célia Monteiro de
RC
Feitosa
Judith Pessoa Andrade
JP
Gomes
Brenda Paula Figueiredo de Almeida
BP
Souza-Filho
Francisco José de
FJ
D001938:Brazil; D002152:Calorimetry, Differential Scanning; D004055:Differential Thermal Analysis; D006171:Gutta-Percha / Q000737:chemistry*; D008422:Materials Testing; D012390:Root Canal Therapy; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013696:Temperature; D013816:Thermodynamics; D013818:Thermogravimetry
D006171:Gutta-Percha