Evaluation of the accuracy of orthodontic models prototyped with entry-level LCD-based 3D printers: a study using surface-based superimposition and deviation analysis

Objectives The objective of this study was to evaluate the accuracy of dental models prototyped via entry-level liquid crystal display (LCD) 3D printers. Materials and methods Identical prototyped models were generated from a master digital file testing two entry-level LCD-based 3D printers and using one professional-grade 3D printer as gold standard (GS), with 50-mu m and 100-mu m layer thickness. Each 3D-printed model was scanned, and a specific 3D technology was used to perform surface-based superimposition and deviation analysis to evaluate trueness and precision. The distances between surface points of two superimposed models were converted to root mean square (RMS) and statistically analyzed. Results The RMS values detected were significantly higher in dental models prototyped with entry-level compared to the SLA printer (p < 0.001), in terms of trueness (50 mu m: GS 0.075 mm, LCD1 0.192 mm, LCD2 0.179 mm; 100 mu m: GS 0.066 mm, LCD1 0.209 mm, LCD2 0.199 mm) and precision (50 mu m: GS 0.028 mm, LCD1 0.075 mm, LCD2 0.085 mm; 100 mu m: GS 0.039 mm, LCD1 0.096 mm, LCD2 0.101 mm). No significant differences were found between the values of RMS of both entry-level 3D printers (p > 0.05). Layer thickness did not affect either the trueness or precision of the 3D-printed models (p > 0.05). Conclusion Entry-level LCD-based 3D printers are not as accurate as professional-grade 3D printer, but still close to orthodontics clinical threshold values.