Alpha- and beta-forms of gutta-percha in products for root canal filling

Aim This study was undertaken to evaluate which materials were in the a-for m 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 studie d; (ii) 12 newer products; and (iii) one newer product that had been stored at high temperature, were analysed by simultaneous differential thermal an alysis and thermogravimetry. Results It was found that only four of the newer materials contained the cc -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 degreesC caused changes in material behaviour - th at is, on reheating fewer endothermic peaks were present. Storage of gutta- percha samples for 10 years under ambient temperature and storage in a heat er at 80 degreesC appeared to have no effect on properties. Conclusions it was concluded that heating dental gutta-percha to 130 degree sC causes physical changes; this was not seen with chemically pure gutta-pe rcha. The presence of additives in the dental samples altered material beha viour.