Accuracy of 3 different impression techniques for internal connection angulated implants

Statement of problem. Making implant impressions with different angulations requires a more precise and time-consuming impression technique. Purpose. The purpose of this in vitro study was to compare the accuracy of nonsplinted, splinted, and snap-fit impression techniques of internal connection implants with different angulations. Material and methods. An experimental device was used to allow a clinical simulation of impression making by means of open and closed tray techniques. Three different impression techniques (nonsplinted, acrylic-resin splinted, and indirect snap-fit) for 6 internal-connected implants at different angulations (0, 15, 25 degrees) were examined using polyether. Impression accuracy was evaluated by measuring the differences in 3-dimensional (3D) position deviations between the implant body/impression coping before the impression procedure and the coping/laboratory analog positioned within the impression, using a coordinate measuring machine. Data were analyzed by 2-way ANOVA. Means were compared with the least significant difference criterion at P<.05. Results. Results showed that at 25 degrees of implant angulation, the highest accuracy was obtained with the splinted technique (mean +/- SE: 0.39 +/- 0.05 mm) and the lowest with the snap-fit technique (0.85 +/- 0.09 mm); at 15 degrees of angulation, there were no significant differences among splinted (0.22 +/- 0.04 mm) and nonsplinted technique (0.15 +/- 0.02 mm) and the lowest accuracy obtained with the snap-fit technique (0.95 +/- 0.15 mm); and no significant differences were found between nonsplinted and splinted technique at 0 degrees of implant placement. Conclusions. Splinted impression technique exhibited a higher accuracy than the other techniques studied when increased implant angulations at 25 degrees were involved.