Effect of Shoulder and Deep Chamfer Finish Lines on Marginal Fitness of Electroformed P.F.M. Restorations

Objective: Comparison of the effect of shoulder with deep chamfer finish lines in P.F.M restorations using electroforming. Method: This experimental study was performed on 20 samples that were randomly selected. Two cutting designs shoulder and deep chamfer were created on dies via a standard turning machine. The diameter rim was 8mm and the height was 6 mm and the depth of cutting edge in cervical area, was 1mm. Impressions were made from dies and 10 acetone dies were prepared for each group. Silver was used on the dies to the finish line and a copper wire was connected to the die by making a foramen 1 mm away from finish line. The collection of die and wire were attached to the head of electroforming machine and gold cooping was created with electroforming. The gap between the die and the crown was measured by electron microscope; data was recorded and evaluated by the t-test.   Results: According to statistical data, the average gap in shoulder lathe was 24.42 microns and in deep chamfer was 20.66 microns.   Conclusions: The deep chamfer design in electroforming method had a better marginal fitness in comparison to the shoulder design.