Laboratory investigation of Accuracy of Impression Materials for Border Molding

Border molding of the edge of the individual impression tray is an important stage of prosthetic treatment of edentulous jaws, which often depends on the final result of the treatment. Classical thermoplastic impression materials for border molding have positive qualities that make them preferable by clinicians for their hardness, unlimited manipulation time and high impression sharpness. Modern silicone impression materials for border molding have long manipulating time and appropriate viscosity to allow dentists to perform functional tests.

To determine the accuracy of different impression materials for border molding of individual impression trays.

Four impression materials for border molding were laboratory tested: Kerr impression compound green sticks and thermoplastic GC Iso functional sticks, additive type silicone Detaseal function and condensation type silicone sta-seal f. A modified individual impression tray designed by authors was used, allowing for laboratory load and stability. Ten impressions were taken and their formed edges were measured at 10 points three times - immediately after hardening/elasification, and 24 hours and 48 hours after hardening/elasification.

The results were analysed using ANOVA repetition analysis, where a statistically insignificant difference in the accuracy of three of the impression materials for border molding was established, except the C-type of silicone.

Good manipulative qualities and measured accuracy in laboratory tests define these materials as very good for border molding procedures.