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-µm and 100-µm 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 µm: GS 0.075 mm, LCD1 0.192 mm, LCD2 0.179 mm; 100 µm: GS 0.066 mm, LCD1 0.209 mm, LCD2 0.199 mm) and precision (50 µm: GS 0.028 mm, LCD1 0.075 mm, LCD2 0.085 mm; 100 µm: 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. Clinical relevance: Clinicians should evaluate the intended application of 3D-printed orthodontic models before using entry-level 3D printers.