Comparative evaluation of microleakage of metallic copings luted with three different commercially available luting cements: An in vitro study

Aim: To evaluate the microleakage of metallic copings luted with three different commercially available luting cements. Setting and Design: Comparative evaluation in vitro study. Materials and Methods: Thirty replicas of abutment analog were milled and divided into 3 groups. Nickel chromium copings were fabricated; marginal gap was evaluated with optical microscope and luted with Zinc Oxide Non Eugenol cement, Zinc Polycarboxylate cement and Zinc Phosphate cement. After Thermocycling, cemented specimens were placed into 0.5% aqueous solution of basic fuchsin solution for 24 hours for dye penetration. Copings were longitudinally sectioned and microleakage scores were evaluated. Statistical Analysis Used: Kruskal-Wallis analysis of variance (ANOVA) followed by Chi-Square test. Pairwise comparison of groups with Mann Whitney U test. Result: Mean microleakage score was least for Zinc Phosphate cement (1.075 +/- 0.85) followed by Zinc Polycarboxylate cement (1.80 +/- 0.23) and most for Zinc Oxide Non Eugenol (2.1 +/- 0.37). The results of the study were statistically significant, P < 0.05. Conclusions: Within the limitations of the study, it was found that all cements exhibited certain amount of microleakage. Zinc Phosphate cement exhibited a mean microleakage score that was significantly lower than Zinc Oxide Non Eugenol cement and Zinc Polycarboxylate cement. When microleakage scores of Zinc Oxide Non Eugenol cement and Zinc Polycarboxylate cement were compared, the difference was found to be insignificant indicating that microleakage in these cements is similar.