Reaction of inflamed periapical tissue to intracanal medicaments and root canal sealers.

The effects of different intracanal medicaments and zinc oxide-eugenol based root canal sealers on an experimentally induced apical periodontitis were studied histologically in mesial roots of lower molars of Wistar rats. After root canal instrumentation each canal was filled either with an intracanal medicament twice for 3 days each time or with a sealer for 21 days. The intracanal medicament chlorophenol caused periapical tissue damage. P-chloroxylenol-camphor lead to periapical improvement as did 5% sodium-hypochlorite. 12% sodium-hypochlorite gave tissue damage. After intracanal medication with an aqueous suspension of calcium hydroxide periapical repair was clearly visible. A combination of a corticoid and an antibiotic appeared to induce damage of the periapical tissues. The root canal sealers Endomethasone and N2 essentially impaired periapical repair. The results were acceptable for Aptal-Zink-Harz root canal fillings after 21 days as well as after 56 days.