comparative study between mineral trioxide aggregate and calcium hydroxide as pulp capping agents in dog's teeth

This study was carried out in order to compare mineral trioxide aggregate [MTA] and dycal in dog's teeth as pulp capping agents. 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 and 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, x [2], Cochran, and Friedman tests. 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. Based on the result of this study, MTA showed to be a more reliable material as pulp capping agent in comparison with calcium hydroxide

[ effect of dental bonding agent of excite on the rate of microleakage in class V amalgam restorations]

This study was done to evaluate the rate of microleakage in class V amalgam restorations in which the dental bonding agent [DBA] Excite was used as a sealer beneath the restorations. four amalgam restorative materials with commercial names of Dentam, Cinalux, Tytin and SDI [GS-80] were used. Seventy sound human premolars were selected and randomly divided into 4 groups of 15 teeth and 2 groups of 5 teeth as negative and positive control groups]. Class V cavities were prepared on the buccal surface of each tooth, Excite was applied on the surface of all cavities and then teeth were cured and restored with four selected amalgam restorative materials. Then teeth were thermocycled [500 cycles] and immersed in 2% methylen blue solution for 24 hours. After immersion, teeth were thoroughly washed with tap's water, and sectioned using a diamond disk. Based on microscopic evaluation and Kruskal-wallis test, Cinalux [An amalgam filling material manufactured in Iran] showed maximum of microleakage in comparison to other amalgam filling materials used in this study, however it's value was not significant