Accuracy of splinted and non-splinted impression techniques for angulated implants in an edentulous mandibular model

Objective: This in vitro study aimed to compare the accuracy of splinted versus non-splinted open-tray impression techniques for angulated implants in an edentulous mandibular model.Methods: In this in vitro study, three acrylic edentulous mandibular models were used, each containing three implants placed at angulations of 0°, 15°, and 25°. Five impressions were obtained from each model using either splinted or non-splinted open-tray techniques (n=5 per technique/angulation, total n=30). The impressions were made using polyvinyl siloxane with either splinted or non-splinted copings. Reference scans obtained from a laboratory scanner served as the gold standard. Three-dimensional (3D) deviations between test and reference datasets were measured using Geomagic Control X software, and the results were analyzed by two-way ANOVA at the significance level of P<0.05.Results: The mean 3D deviations were 57.90 ± 12.65 µm for non-splinted impressions and 61.84 ± 15.84 µm for splinted impressions. The mean deviation was lowest at 15° (56.38 ± 14.83 µm) and highest at 25° (64.44 ± 14.62 µm).No significant difference was observed in the accuracy of different impression techniques (P=0.535). Furthermore, implant angulation did not significantly affect impression accuracy (P=0.401).Conclusions: Within the limitations of this study, the splinted open-tray technique demonstrated comparable accuracy to the non-splinted technique. Implant angulation up to 25° did not significantly affect the precision of splinted and non-splinted open-tray impressions.