E C Combe1, B D Cohen, K Cummings. 1. Minnesota Dental Research Center for Biomaterials and Biomechanics, University of Minnesota School of Dentistry, Minneapolis 55455, USA. combe001@tc.umn.edu
Abstract
AIM: This study was undertaken to evaluate which materials were in the alpha-form of gutta-percha as claimed, and which were in the more conventional beta-form, and to explore the effect of heating on the materials. METHODOLOGY: Samples of gutta-percha without chemical additives, and dental gutta-percha formulations which included (i) two products previously studied; (ii) 12 newer products; and (iii) one newer product that had been stored at high temperature, were analysed by simultaneous differential thermal analysis and thermogravimetry. RESULTS: It was found that only four of the newer materials contained the alpha-form; all the rest comprised beta-gutta-percha. No weight loss was found for any material under the conditions of the present experiments. A typical heating cycle up to 130 degrees C caused changes in material behaviour - that is, on reheating fewer endothermic peaks were present. Storage of gutta-percha samples for 10 years under ambient temperature and storage in a heater at 80 degrees C appeared to have no effect on properties. CONCLUSIONS: It was concluded that heating dental gutta-percha to 130 degrees C causes physical changes; this was not seen with chemically pure gutta-percha. The presence of additives in the dental samples altered material behaviour.
AIM: This study was undertaken to evaluate which materials were in the alpha-form of gutta-percha as claimed, and which were in the more conventional beta-form, and to explore the effect of heating on the materials. METHODOLOGY: Samples of gutta-percha without chemical additives, and dental gutta-percha formulations which included (i) two products previously studied; (ii) 12 newer products; and (iii) one newer product that had been stored at high temperature, were analysed by simultaneous differential thermal analysis and thermogravimetry. RESULTS: It was found that only four of the newer materials contained the alpha-form; all the rest comprised beta-gutta-percha. No weight loss was found for any material under the conditions of the present experiments. A typical heating cycle up to 130 degrees C caused changes in material behaviour - that is, on reheating fewer endothermic peaks were present. Storage of gutta-percha samples for 10 years under ambient temperature and storage in a heater at 80 degrees C appeared to have no effect on properties. CONCLUSIONS: It was concluded that heating dental gutta-percha to 130 degrees C causes physical changes; this was not seen with chemically pure gutta-percha. The presence of additives in the dental samples altered material behaviour.
Authors: Claudio Maniglia-Ferreira; Eduardo Diogo Gurgel-Filho; João Batista de Araújo Silva-Jr; Regina Célia Monteiro de Paula; Judith Pessoa de Andrade Feitosa; Francisco José de Sousa-Filho Journal: Eur J Dent Date: 2013-04