RESUMO
Samples of three common commercial gutta-percha endodontic filling points (Hygienic, Mynol, and Maillefer Pink) and a sample of natural gutta-percha were submitted to thermomechanical analysis under pressures ranging from 0.01 to 0.2 N. Samples of Mynol and Maillefer filling points were thermally treated and then submitted to thermomechanical analysis in parallel with differential scanning calorimetric analysis. The results show that thermomechanical analysis gives results distinct from those obtained by classic dilatometry and that it is a technique well suited to the study of the thermoplastic properties of gutta-percha. An analysis of the results shows that the amount of the inorganic component used in a commercially available endodontic point has a strong influence on its thermomechanical properties. Thermodynamical properties and the "thermal history" of the gutta-percha are also important. Both temperature and force should be controlled in order to assess the thermomechanical properties of endodontic filling points, while the latter have not yet been codified in clinical procedures.
