The Effect Of Stiffness Of Impression Materials And Flexibility Of Trays On The Casting Accuracy (An In-Vitro Study)

To study the result of utilizing two impression materials of various stiffness with three impression trays of variable flexibility on the marginal casting accuracy of metal cores.Materials and Methods: The lower first molar of an acrylic model mounted to a semi-adjustable articulator was made for a full veneered metal coping.Thirty impressions were prepared with metal triple impression trays, plastic triple impression trays and a resin custom made tray using polyvinyl siloxane and polyether impression materials.Each was cast in type IV hard dental stone and the occlusogingival, mesiodistal and buccolingual dimensions of the obtained dies were measured using a traveling microscope and the prepared tooth served as a control.Wax patterns were fabricated on each stone die then cast into metal copings.Each metal coping was fitted on the prepared tooth and examined for vertical marginal gap accuracy using the travelling microscope.One-way ANOVA followed by pair-wise tukey's post-hoc tests were performed to detect the significance between groups, then separate