Objectives: The aim of this study was to investigate the accuracy of CAD/CAM-fabricated bite splints in dependence of fabrication method (milling vs 3D printing), positioning (horizontal vs vertical), selection of material, and method of deviation measurement.
Materials and methods: Bite splints were 3D-printed in either horizontal or vertical position (n = 10) using four different resins (Dental LT, Ortho Clear, Freeprint Splint, V-Splint). As control, ten bite splints were fabricated by CNC milling (ProArt CAD Splint). The splints were scanned and deviations between the CAD-file (trueness) and between each other within one group (precision) were measured by two different software applications and methods (cloud-to-cloud vs cloud-to-mesh). Data were analyzed using univariate analysis, Kolmogorov-Smirnov, Kruskal-Wallis, and Mann-Whitney U tests.
Results: The highest impact on accuracy was exerted by the selection of the material (trueness: ηP2 = 0.871, P < 0.001; precision: ηP2 = 0.715, P < 0.001). Milled splints showed the highest trueness (P < 0.01) but not the highest precision at the same time. Horizontally positioned 3D-printed bite splints showed the least deviations in terms of trueness while vertical positioning resulted in the highest precision. The cloud-to-cloud method showed higher measured deviations than the other methods (P < 0.001-P = 0.002).
Conclusion: Milled splints show higher trueness than 3D-printed ones, while the latter reveal higher reproducibility. The calculated deviations vary according to the measurement method used.
Clinical relevance: In terms of accuracy, milled and 3D-printed bite splints seem to be of equal quality.
Keywords: Accuracy; Bite splints; CNC milling; Precision; Three-dimensional printing; Trueness.