Objectives: Stereolithography (SLA) is based on spatial solidification of a liquid resin by photo-polymerization . Due to its precision and surface smoothness, SLA is particularly suitable for printing maxillofacial models used in surgical planning or dental training .
Dental SG is a certified biocompatible Class 1 material  developed specifically for surgical guides in dentistry. Such 3D-printed guides may improve pre-operative planning, implant placement and patient comfort . However, this newly developed resin and its usability in the medical field have yet to be researched thoroughly.
This work aims to determine mechanical properties of printed objects using Dental SG.
Materials and Methods: To evaluate isotropy in respect to print direction relative to the XY-plane, flexural strength and Young’s modulus are determined in a three-point flexural bending test based on DIN EN ISO 4049.
Three groups (n=10 for each) are printed with a layer height of 0.05 mm and dimensions of 5x5x30 mm. The first group is printed at an angle of 0° (horizontally), the second group at 45° and the third at 90° (vertically) relative to the XY plane.
Results: Mean ±SD flexural strength and Young’s modulus for vertically printed specimens are 135.69 (±5.93) MPa and 1456.73 (±149.83) MPa. Comparable with 130.73 (±5.12) MPa and 1467.56 (±89.36) MPa for specimens angled at 45°. The measured values for horizontal prints are 117.48 (±12.39) MPa and 1654.38 (±152.27) MPa. Means of the horizontal group are statistically different on a p=0.05 level (ANOVA, Post Hoc Tukey HSD) compared with the two other groups.
Conclusion: This study concludes that SLA prints using Dental SG are isotropic. Printing direction does not influence flexural strength and Young’s modulus. Due to SLA-printing characteristics, first layers are compressed, resulting in a lower height (mean 4.5 ±0.1 mm) of horizontal prints. Differing values are attributable to variances in height.