The accuracy of six impression techniques for osseointegrated implants.

PURPOSE Six impression techniques were evaluated using tapered and square impression copings. MATERIALS AND METHODS The absolute distortion was measured using a cast metal impression tray with fiduciary reference points external to the impression material. Measurements of the x, y, z coordinates on the master cast and the impressions were directly made with a travelling digitizing microscope. The difference between the coordinates of each of six sites in the impression and the corresponding reference site were compared. RESULTS There was no significant difference between the techniques for the square copings but that there was a significant loss of accuracy in the z-axis with the tapered copings. CONCLUSIONS No significant differences were noted.