A study on the adhesion of restorative materials to irreversible hydrocolloid impression materials.

Aim: The purpose of this study was to evaluate the adhesion of restorative materials to irreversible hydrocolloid impression materials.
Materials and Methods: Three irreversible hydrocolloid impression materials were tested with four restorative materials: a base metal alloy, an amalgam, an autopolymerising resin composite and a heat polymerising resin. Samples were prepared with and without a collar. Half of the samples were cleaned with methanol by wiping. The other half were not methanol-wiped. All the samples were submerged into the impression materials and were subsequently placed in an impression- holding device in two different positions. A pullout test using a Hounsfield machine was used after the impression materials were set.
Results: Variance analysis was used in comparing the results obtained. Statistically, the four restorative materials showed different values regarding the adherence of the impressions materials to them (composite resin 52.47N, metal 26.36N). Samples with adherence to a collar were found to be more retentive than those without a collar. Samples with impression materials with a full collar were more retentive than those without a collar, and the samples cleaned with methanol were again less retentive than those which were not methanol wiped.
Conclusion: The results of this study show that adhesion may be seen between restorative materials and irreversible hydrocolloid impression materials, and this adhesion may affect the accuracy of the impression.