M. Bernath & J. Szabo.Department of Dentistry and Oral Surgery, Faculty of Medicine, Pecs University, Pecs, Hungary.
Periapical tissue reaction after root canal treatment and/or obturation may be influenced by various factors, including pre-existing disease, elimination of pulp tissue, shaping and cleaning of the root canal system, bacterial infection, filling technique and chemical nature of the sealer (Block et al. 1976; 1985, Taintor et al. 1979, Moller et al. 1981, Walton & Torabinejad 1989, Odesjoet al. 1990). The tissue reaction initiated by sealers can be tested by the analysis of root canal treatment failures in humans (Block et al.1976;1985), but these observations do not meet the requirements of objective nonbiased testing (Pascon et al.1991). To gain valuable information about the tissue reaction of root canal filling and select the appropriate sealer, the sealers should be tested in animal models. Nonhuman primates provide the best animal model for these studies because the anatomy of the teeth and the periradicular tissues are similar to those of humans, and the commonly available endodontic instruments for human teeth and filling materials can be used without modification (Pascon et al.1991).
The number of studies that have evaluated the tissue reactions after root canal filling in nonhuman primates are limited and some of the results are conflicting. Pascon et al. (1991) compared the sealers of Kloroperka N.C. (Union Broach Corp., Long Island City, NY, USA), Kerr Pulp Canal sealer (Rickert modified, Sybron/Kerr, Romulus,MI, USA) and AH26 (DeTrey Dentsply, Zurich, Switzerland) in baboons, and found that the severity of periapical tissue reactions varied between materials. In contrast, Crstavik & Mjor (1992) used AH26 (DeTrey AG, Zurich, Switzerland), Endomethasone (Septodont, Paris, France), Kloroperka N-C (NC Therapeutics, Oslo, Norway) and ProcoSol (Star Dental, Conshohocken, PA, USA) in Macaca fascicularis, but found no differences in tissue reactions caused by the endodontic materials. Finally, calcium hydroxide sealers had been tested in rats, dogs and monkeys, but the tissue reactions initiated by these sealers were different (Pitt Ford & Rowe 1989, Tagger & Tagger 1989, Leonardo et al. 1997, Maita et al. 1998, Lupa et al.1999).
The aim of this study was to analyse the tissue reactions of the calciumhydroxide sealer Apexit and to compare it with the reactions of sealers with different chemical compositions (Endomethasone, AH26 and Grossmanâ€™s sealer).