Effect of build angle and layer height on the accuracy of 3-dimensional printed dental models

Abstract

Three-dimensional (3D) printing technologies are profoundly changing the landscape of orthodontics. To optimize treatment-oriented applications, dimensional fidelity is required for 3D-printed orthodontic models. This study aimed to evaluate the effect of build angle and layer height on the accuracy of 3D-printed dental models and if each of their influences on print accuracy was conditional on the other. A maxillary cast was scanned using an intraoral scanner. One hundred thirty-two study models were printed at various combinations of build angle (0°, 30°, 60°, 90°) and layer height (20μm, 50μm, 100μm) with a digital light processing printer (n=11 per group). The models were digitally scanned, and deviation analyzed using a 3D best-fit algorithm in metrology software. A statistically significant interaction was consistently found between build angle and layer height for each positive deviation, negative deviation, and proportion out of bounds. Average deviations of all study models were within clinically acceptable ranges, but the least accurate models were printed at 0°/20μm. Although there was a tendency for an oblique build angle of 30° or 60° with a smaller layer height of 20μm or 50μm to print the most accurate models, 95% confidence intervals overlapped with all other angles and heights except for 0°/20μm. Build angle and layer height have statistically significant interactive effects on the accuracy of 3D-printed dental models. Overall, digital light processing printers produced models within clinically acceptable bounds, but the choice of build angle and layer height should be considered in conjunction with the clinical application, desired print time, and preferred efficiency of each print job.