LABORATORY EVALUATION OF MARGINAL PORCELAIN EXTENSION ON MICROLEAKAGE OF BASE METAL CROWNS

Introduction: The purpose of this study was to evaluate the marginal porcelain extension on microleakage of base metal – porcelain crowns when four types of luting cements have been used for cementation. Materials & Methods: In this invitro experimental study, ninety six base metal-porcelain crowns with three types of finishing margins were made for premolars. Then they were luted with four different luting cements (zinc phosphate, zinc polycarboxylate, glass ionomer and Panavia F). Next, they were thermocycled (1000 times). Finally, the microleakage was measured after dye penetration. For data analysis, Non parametric Kruskal-Wallis and Mann-Whithney tests were used (µ=0.05). Result: The mean rank of microleakage in buccal margin was more than lingual one (P<0.05). In all of the finishing margins, zinc phosphate cement showed the highest microleakage in buccal and lingual walls (P<0.05). In all of the finishing margins, Panavia F showed the least microleakage compared to the other cements in two walls (P<0.05). Conclusion: For promotion of marginal seal in base metal – porcelain crowns, the use of Panavia F as a luting cement is suggested.