Influence of the print orientation and cast thickness on the accuracy of DLP master casts for fixed dental prostheses

Abstract

Abstract Background This study aimed to evaluate the influence of different print orientations and external shell thickness on the accuracy of master casts printed with direct light processing (DLP) technology for fixed dental prostheses. Methods Seventy-two maxillary hollow master casts were printed with a DLP printer from a standard tessellation language (STL) reference file with dental preparations for a single crown and a 3-unit fixed partial denture. Study groups consisted of six groups (n = 12) according to the print orientation (0, 10, and 20 degrees) and the external shell thickness of the cast (2 mm and 4 mm). Each specimen was digitized with a laboratory scanner. Discrepancies between the reference STL and the experimental STL of the printed cast were measured by using the root mean square (RMS) error. Data were statistically analyzed using one-way ANOVA and Tukey’s HDS test to evaluate the trueness, and precision was assessed using the Levene test (α = 0.05). Results No significant differences were found in the overall trueness and precision between the groups analyzed for the print orientation and the shell thickness. The 2-mm external shell thickness demonstrated the best trueness on selected points. Conclusions The print orientation in the range of 0 to 20 degrees and the cast thickness did not influence the overall accuracy of DLP-printed master casts for fixed prostheses with clinically acceptable range values. Trueness was affected by the external shell thickness on selected points.

Keywords

• Dental casts
• Accuracy
• 3DPrinting
• Direct light processing printer
• Print orientation
• External shell thickness