Since the study of root canal filling combined with gutta-percha points and endodontic cement by Dixon and Rickert, many other studies have made use of radiographic evaluation. However, histopatholgical evaluations are infrequent and often incomplete in terms of findings. In this chapter we report the results of our examination using gutta-percha points and a new endodontic cement called KEZ with powder components: 40% zinc oxide, 20% calcium hydroxide, 20% iodoform, and 20% resin; and liquid components: 90. 5% eugenol, 9% resin and 0.5% setting agent. One hundred dog teeth were perforated using a rotary cutting instrument. The exposed pulp chamber was left opened for 30 days. Rotary reamers were used to perforate the infected root canals at the apical portion. They were cleaned with sodium hypochlorite and saline solution. Fifty canals were filled with combined gutta percha and KEZ. In the other fifty, no root canal filling was used and the teeth were restored with amalgam. Three months later the dogs were sacrificed and specimens for histopathological evaluation were prepared. Resuts were as follows. Root canals filled with a combination of guttapercha and KEZ manifested proper sealing of the apical apex, appropriate radiopacity, and reliable healing of the apical periodontal tissues. In unfilled root canals, no reparative change occurred. Moreover, when root canals were filled, alveolar bone regeneration, closure of the root apex and cicatrization of the periodontal tissue in deep layers occurred. In addition, sealing of the artificially-made apical foramen was observed in some cases. When canals were filled, both inflammatory cell infiltration and suppuration tended to decrease. Alveolar bone resorption and closure of the root apex occurred as a consequence of new cementum or bone deposition.
Editor, Toshiyuki Kawakami
Language Editor, David M Carlson
viii, 232 p. ill. (some col.)
Chapter 11 : Histopathological Evaluation of Combined Root Canal Filling: An Animal Study
