A Comparative Study of Apical Healing of Open Apices Using MTA and Ca(OH)2 Apical Plugs in Cats

Statement of problem: Endodontic treatment of necrotic teeth with open apices is a challenge. After ruling out surgery as a treatment scheme and introduction of the multivisit apexification which in turn had its disadvantages, apical plug seems to be a suitable substitute treatment plan for such cases. Apical plug makes the treatment through formation of a barrier against the obturating material in a single visit. Purpose: The purpose of this study was to compare histologically the periapical healing using MTA and calcium hydroxide apical plugs after intervals of 4 and 12 weeks in cats. Materials and Methods: In this clinical trial study 64 canines of 16 healthy and mature cats were divided into 3 groups after a periapical lesion formation by over instrumentation in the apical area with files up to no.120. The first group included 24 teeth on which MTA apical plug was applied. The second group included 24 teeth on which Ca (OH) 2 apical plug was applied. In both groups the canals were filled with gutta percha and sealer. The third group included 16 control teeth whose canals were left empty after instrumentation and debridement. The access cavities of all teeth were sealed with varnish and amalgam and the vital perfusion of cats was performed in 4 and 12 week intervals. Statistical analysis was established by χ2 and independence test. Results: After 4 weeks, periapical healing in the first group was 90%, in the second group 80% and in the third group, it was only 12.5 %. After 12 weeks, periapical healing occurred in 100% of the MTA group, while it was 57.1% in the second and 40% in the third group .Generally, in the study of histological parameters of healing, no statistical significant difference was observed between the 2 experimental groups, although the MTA group results were much better than the Ca (OH) 2 group especially at 12 weeks. Conclusion: The use of MTA apical plug is more effective than Ca (OH) 2 in treatment of necrotic teeth with open apices.