When heated, it is less adhesive and flowable than the alpha form 9. The beta form, on the other hand, is stable and flexible at room temperature. The alpha form of gutta-percha is brittle at room temperature, but becomes gluey, adhesive and highly flowable when heated. Most gutta-percha cones available are in the beta form. Gutta-percha is a polymer found in two distinct crystalline forms, alpha and beta. The lateral condensation method using cold gutta-percha may result in voids between the cones 1, 12, 14 and lack of a homogeneous sealing mass 4, 19. Root canal filling techniques using cold or warm gutta-percha cones have been extensively applied in Endodontics 12, 14, 19, 24. These differences may affect the physical and biological properties of gutta-percha cones 21. 16(2005) studied the chemical composition of some Brazilian guttapercha cones and found a variation from 15.2 to 21.6% for gutta-percha and from 69.8 to 81.9% for zinc oxide. 11 (2003) compared five commercial brands of cones and found variations from 14.5% to 20.4% for gutta-percha, and from 66.5% to 84.3% for zinc oxide.
Gutta-percha cones consist mainly of gutta-percha and zinc oxide 11, 16, 20 in variable ratios, depending on the manufacturing methods. Gutta-percha, used since 1867 6, is the most commonly employed material due to its biocompatibility, dimensional stability, plasticity, and ease of removal when necessary. Several materials and techniques have been used to fill the root canal system. For endodontic therapy to be successful, it is acknowledged that the root canal should be cleaned, shaped and sealed in its three dimensions 19.
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