Accuracy of different impression techniques for multiple implants angulated to each other: An in vitro study

Abstract

Aim and objective: To evaluate the accuracy of different impression techniques - namely the closed tray impression technique, the open tray non-splinted impression technique, the open tray splinted technique and an experimental technique for multiple implants placed at an angulation with each other. Materials and Methods: A master model was made of die stone which incorporated four implants having an internal hexagonal connection. The two terminal implants were placed at an angle of 20 degrees (lingually) whereas the two central implants were placed perpendicular to the cast. The samples were divided into four groups (Group I: Closed tray impression technique, Group II: Open tray impression technique non-splinted, Group III: Open tray impression technique splinted and Group IV: Experimental technique) based on the impression technique used. P-values were obtained using one-way analysis of variance (ANOVA) with Tukey’s correction for multiple group comparisons.Results: The P-value was greater than 0.05 (0.869) for Group III. Therefore, open tray splinted technique (Group III) was the most accurate impression technique when compared to the other techniques. On Inter - group comparisons it was noted that the values obtained by experimental technique were within close range of the values obtained by open tray splinted impression technique. Whereas, a comparison of Group I with Group III revealed 2 points of statistical significance (2 points of inaccuracy). Comparison of the Group II with Group III showed that all the points were statistically significant (all points were inaccurate). Conclusion: The open tray splinted impression technique provides best results for multiple implants placed at varying angulations. The experimental technique can be beneficial in areas of limited access, reduced mouth opening and exaggerated gag reflex.