To Evaluate the Marginal Adaptation of Porcelain Fused to Metal Crown with Different Base Metal Alloys

The success of any restoration depends on the marginal seal. The adaptation of castings, luting cement, and the surface structures of the margins are all important factors in achieving marginal seal.

The aim of this study was to evaluate the vertical marginal discrepancy of cast copings obtained by employing conventional casting technique with two different base metal alloys with two different finish lines before and after porcelain firing.

A total of forty wax copings were fabricated with stainless steel die assembly and divided into four groups with ten specimens for each metal and each finish line. Measurements were recorded from coping margin to the stainless steel die margin for vertical marginal gap recordings. Each metal coping was finished, and porcelain application was completed. Copings with porcelain were placed on their respective dies, again subjected to the same measuring microscope for checking the vertical marginal discrepancy by the same operator and results.

The results of the present study showed that the mean vertical marginal gaps of all the cast copings obtained in each group (G1-G8) were within clinically acceptable limits. The mean vertical marginal gap of G1 was 135.36 ± 2.30 μm, G2 was 67.22 ± 4.25 μm, G3: 39.47 ± 2.98 μm, G4: 71.00 ± 3.97 μm, G5: 109.57 ± 2.98 μm, G6: 109.57 ± 2.98 μm, and G8: 114.58 ± 2.40 μm.

The difference in the vertical marginal gap of cast copings obtained in different groups was statistically highly significant at 0.005 level, while the difference in the vertical marginal gap of cast copings obtained at different points was statistically nonsignificant.