An evaluation of printing orientation on the trueness and dimensional accuracy of two resin materials over nine months

Abstract

Objective: To evaluate the effect of printing orientation on the dimensional accuracy, trueness, and 9-month stability of two 3D-printed dental resins. Methodology: In this in vitro study, 108 specimens of Model Resin Material (MRM) and Interim Prosthesis Material (IPM) were printed at 0°, 45°, and 90° (n=9/group). Specimens were scanned immediately and after nine months using a 3Shape lab scanner. Dimensional accuracy was assessed by linear measurements and trueness by RMS deviation using GOM Inspect. Data were analyzed with ANOVA (α=0.05). Results: Printing orientation had no significant effect on dimensional accuracy or trueness (p>0.05). All groups showed significant post printing shrinkage (p<0.05). IPM demonstrated better trueness (0.231±0.051 mm) than MRM (0.498±0.168 mm; p=0.001) and maintained superior dimensional stability after nine months (p=0.001). Conclusion: Printing orientation minimally affects accuracy. IPM shows better trueness and long term stability than MRM, and surface based analysis detects deviations not identified by linear measurements.