Influence of the three-dimensional printing technique and printing layer thickness on model accuracy

ObjectiveThe accuracies of three-dimensional (3D) printed dental models using various digital light processing (DLP) and stereolithography (SLA) printers at different thicknesses were compared.Materials and methodsBased on digital dental models (originally digitized using R700; 3Shape, Copenhagen, Denmark), physical dental models were printed using three types of DLP printers:(1) EvoDent (UnionTec, Shanghai, China) with layer thicknesses of 50m and 100m; (2) EncaDent (Encashape, WuXi, China) with layer thicknesses of 20, 30, 50 and 100m; (3) Vida HD (Envisioned, Dearborn, MI, USA) with layer thicknesses of 50 and 100m. Models with the SLA printer Form2 (Formlabs, Somerville, MA, USA) were printed with layer thicknesses of 25, 50 and 100m. All 22 printed models were converted to digital dental models using aD2000 model scanner (3Shape, Copenhagen, Denmark) and compared three-dimensionally to the source files using Geomagic Qualify 12.0 (3D Systems, Rock Hill, SC, USA).ResultsThe printing accuracy of all printers was higher at 50m. When the layer thickness was set at 100m, the printing speed and printing accuracy of DLP printer were both superior to those of the SLA printer. In all groups, the EvoDent 50m group had the highest consistency with the source files (mean absolute deviation of 0.0233mm in the maxilla and 0.0301mm in the mandible). While the accuracy of Form 2 100m group was the lowest (mean absolute deviation of 0.0511mm in the maxilla and 0.0570mm in the mandible).ConclusionFor the 3D printers studied, 50m was the optimum layer thickness for DLP technology, and the printing accuracy using SLA technology increased with decreasing layer thickness. The DLP technology also had higher printing accuracy at alayer thickness of 100m. EvoDent 50m had the highest and Form 2 100m the lowest printing accuracy.