A Comparative Study between Mineral Trioxide Aggregate and Calcium Hydroxide as Pulp Capping Agents in Dog s Teeth

Introduction
This study was carried out in order to compare mineral trioxide aggregate (MTA) and dycal in dog’s teeth as pulp capping agents.
Methods
After general and local anesthesia forty-two teeth of three dogs were used. In each tooth a class V cavity was prepared and the pulp was exposed using No.1 round bur. Then the exposed area was capped using either MTA or calcium hydroxide and the rest of the cavity was restored by amalgam. Radiographic image was taken before the procedure and after 4, 8 , and 12 weeks. The animals were sacrificed at 4, 8, and 12 weeks and the teeth were prepared for H&E staining. The pulps of the teeth were evaluated for inflammation, necrosis, and formation and thickness of calcified bridge. Histologic data were analyzed by Kruskal Wallis, אַ², Cochran, and Friedman tests.
Results
Histopathologic results showed that in four weeks, MTA had significant differences with calcium hydroxide in the presence and thickness of calcified bridge (p=0.046) as well as inflammation (p= 0.014) and hyperemia (p=0.014). Eight weeks MTA specimens showed significant difference in thickness of calcified bridge (p=0.008). Twelve weeks after pulp capping, the amount of necrosis and chronic inflammation were higher in dycal specimens; however, there was no significant difference between two experimental groups. Radiographic evaluation did not show any periapical lesion, internal and external resorption, or widening of periodontal ligament in none of the teeth at all time intervals.
Conclusion
Based on the result of this study, MTA showed to be a more reliable material as pulp capping agent in comparison with calcium hydroxide.