Trueness of Stereolithographic Model Compared to Conventional Model Using CAD/CAM Prosthesis with Digital Photographs

Abstract

Objective: Accuracy of the stereolithographic (SLA) model significantly influences their laboratory uses. The aim of this study was to compare the accuracy of SLA models created from digital impressions to conventional die stone models obtained from elastomeric impressions using full anatomic CAD/CAM fabricated fixed prosthesis. 
 Methods: A partially edentulous typodont model was prepared for this study with two-implant abutments as a reference model. Two impression techniques were used to fabricate study models. Group one (n=5), SLA models were created from digital impressions acquired by an intra-oral scanner. While in group two (n=5), die stone models obtained from vinyl polysiloxane impression materials (VPS). A full anatomic zirconia bridge was fabricated using CAD/CAM system and high-resolution digital photographs from the buccal surface were captured using a macro lens . The vertical distance between selected points was measured by three evaluators using a calibrated digital software program. The t-test with 95% confidence interval was used to evaluate the accuracy of the models.
 Results: There was a strong agreement among observers with a statistically significant difference in the seating of prosthesis on the SLA model versus the conventional model, with a mean and standard deviation of -0.17±0.24 mm and 1.04±0.22 mm subsequently. Their results of the t-test were showed fewer errors in the SLA group.
 Conclusions: CAD/CAM fabricated bridge was better seated on SLA models from digital impressions compared with die stone models from elastomeric impressions. Therefore, the trueness of 3D printed models was greater than conventional models compared to the reference model.