A comparative evaluation of microleakage in three different luting agents used for posterior full metal crown: An in vitro study

The purpose of the study was to evaluate and compare the microleakage at the margins of nickel – chromium full metal crowns cemented with Zinc Phosphate cement, glass ionomer cement. And resin cement.: thirty freshly extracted human molars were selected for the study. Standardized tooth preparation is done with the help of customized metal zig attached to dental surveyor. On prepared teeth castings were fabricated and devided into three groups for the three luting agents namely zinc phosphate cement – Harvard, Glass ionomer cement – Ketac Cem and Resin cement – Rely X U200, each containing 10 samples. After cementation the cemented specimens were stored in artificial saliva for 24 hours. The teeth were then thermocycled between 5°C and 50°C and then treated with 50% silver nitrate stain for 60 minutes. Samples were placed under 150 watt flood lamp for 5 minutes to allow proper fixation of unfixed stain. Then they were embedded in clear acrylic resin and sectioned twice longitudinally. The sections were observed under the stereomicroscope and stain penetration were recorded at tooth cement interfaces. The readings were tabulated and analyzed statistically using Mann-Whitney U test and Kruskal-Wallis H test. .Zinc phosphate cement showed significantly maximum microleakage as compared to glass ionomer cement and resin cement. Resin cement showed significantly less microleakage as compared to glass ionomer cement and zinc phosphate cement. Glass ionomer cement showed more microleakage as compared to resin cement but less as compared to zinc phosphate cement