Effect of print layer height and printer type on the accuracy of 3-dimensional printed orthodontic models

Introduction: Three-dimensional (3D) printing technologies enable production of orthodontic models from digital files; yet a range of variables associated with the process could impact the accuracy and clinical utility of the models. The objective of this study was to investigate the effect of print layer height on the accuracy of orthodontic models printed 3 dimensionally using a stereolithography format printer and to compare the accuracy of orthodontic models fabricated with several commercially available 3D printers. Methods: Thirty-six identical models were produced with a stereolithography-based 3D printer using 3 layer heights (n = 12 per group): 25, 50, and 100 mm. Forty-eight additional models were printed using 4 commercially available 3D printers (n = 12 per group). Each printed model was digitally scanned and compared with the input file via superimposition analysis using a best-fit algorithm to assess accuracy. Results: Statistically significant differences were found in the average overall deviations of models printed at each layer height, with the 25-mu m and 100-mu m layer height groups having the greatest and least deviations, respectively. Statistically significant differences were also found in the average overall deviations of models produced using the various 3D printer models, but all values fell within clinically acceptable limits. Conclusions: The print layer height and printer model can affect the accuracy of a 3D printed orthodontic model, but the impact should be considered with respect to the clinical tolerances associated with the envisioned application.