Objectives: The purpose of our research is identify the molecular characteristics that are responsible for different behaviour in the clinical setting. Methods:EPR were performed to explore direction and crystallisation amount of the dental polymer. A NMR, a NOESY and an X-ray diffraction analysis was made to verify the presence of an isomeric chain of the polymer. We record the dilatometric volumetric variations as a result of thermic analysis to find the hysteresis thermal cycles of the dental gutta-percha during fever or others fluctuations of temperature. Differents conditions of dentine were performed: dry or wet, with hypoclorite, blood, saliva, EDTA. Results: All of the gutta-percha samples demonstrated the presence of some organic impurity. The gutta-percha Microseal Cartridges was found to be the best chemically, with the lowest presence of organic impurity. A strong Overhauser correlation between methyl group and the olefinic proton in the NOESY analysis should be compatible with the isomeric alpha form and indicate that in deuterochloroform solution all samples assume an isotattic conformation. EPR has found differences between crystallisation amount of the polymer net. The low viscosity and high flow capacity of new guttapercha "Ą" behaviour demonstrate a high adhesive capacity to the surfaces in which they come in contact with, but there are differences in clinical situations. Conclusions: To promote the best adhesion to the canal walls, as well as to research an intimate contact through the immission of the gutta-percha to the root canals it would be better to dry as much as possible. These new gutta-perchas present, in respect to the older generation, with different microscopic and macroscopic aspects, as well as dissimilar behaviours to thermal and mechanical stress. Best fluidity of the gutta-percha leading to the best canal therapy, but we are not certain of the different behaviour attributable to thermo-mechanical action during years.

Back to the Dental Materials: VIII - Others-Non-metallic Program
Back to the 81st General Session of the International Association for Dental Research (June 25-28, 2003)

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