Evaluation of three impression techniques for osseointegrated oral implants.

The purpose of this in vitro investigation was to determine the accuracy of gypsum casts produced from impressions made with polyether, polyether and impression plaster, or polyether and acrylic resin for the fabrication of osseointegrated implant prostheses. Strain gauges were attached to a master framework to determine the passivity of fit of the framework to sample casts made by the three impression techniques. Strain values were statistically compared by one way analysis of variance and Duncan's multiple range test. A statistically significant difference was found between the three impression techniques tested (p < 0.05). The results of this investigation revealed that none of the impression techniques resulted in an absolutely passive framework fit. However, of the techniques tested, the polyether alone resulted in the closest duplication of the master cast.