IADR Abstract Archives
Effect of Wall-Thickness on Accuracy of 3D-Printed Zirconia Artificial Teeth
Objectives: The purpose of this study was to analyze how the wall thickness of 3D-printed hollow zirconia teeth affects the shape accuracy.
Methods: Data sets for the different artificial teeth resembling a mandibular right first molar were created (Geomagic design X, 3D systems) with planar, horizontally oriented measurement points at the mesiobuccal (MB), distobuccal (DB), mesiolingual (ML), and distolingual (DL) cusp as well as parallel areas on the buccal and lingual basal surface (BB and LB). Pairs of parallel and vertically oriented surfaces were added for the buccolingual (B-L) and the mesiodistal (M-D) direction. Reference distances were 7.0 mm for MB-BB and DB-BB, 4.5 mm for ML-LB and DL-LB, 10.9 mm for B-L, and 9.8 mm for M-D. For all artificial teeth with wall thicknesses of 0.30 mm, 0.50 mm, 0.75 mm, and 1.00 mm, the outer geometry was identical. Then, 20 zirconia teeth were fabricated using a 3D printer (CeraFab 7500 Dental, Lithoz) for each group, and sintered before support removal. First, distance measurements were carried out with a micrometer screw. Second, angular deviations between the measurement points were analyzed based on 3D scans. Possible effects were investigated by use of Kruskal-Wallis test and the Steel-Dwass method.
Results: Sufficient shape accuracy was given for artificial teeth with wall thicknesses of 0.5 mm or greater. Largest distance deviations were observed for 0.3 mm wall thickness, in particular DB-BB showed median deviation above 56.2 µm, which was significantly larger than those found for the other test groups ranging from 7.4 µm to 9.5 µm (p<0.05). In most cases, angular deviations were also largest for teeth with 0.3 mm wall thickness (11.6°) and remained below 5.0° for the other test groups.
Conclusions: Sufficient accuracy was given for artificial teeth with at least 0.5 mm wall thickness.
Methods: Data sets for the different artificial teeth resembling a mandibular right first molar were created (Geomagic design X, 3D systems) with planar, horizontally oriented measurement points at the mesiobuccal (MB), distobuccal (DB), mesiolingual (ML), and distolingual (DL) cusp as well as parallel areas on the buccal and lingual basal surface (BB and LB). Pairs of parallel and vertically oriented surfaces were added for the buccolingual (B-L) and the mesiodistal (M-D) direction. Reference distances were 7.0 mm for MB-BB and DB-BB, 4.5 mm for ML-LB and DL-LB, 10.9 mm for B-L, and 9.8 mm for M-D. For all artificial teeth with wall thicknesses of 0.30 mm, 0.50 mm, 0.75 mm, and 1.00 mm, the outer geometry was identical. Then, 20 zirconia teeth were fabricated using a 3D printer (CeraFab 7500 Dental, Lithoz) for each group, and sintered before support removal. First, distance measurements were carried out with a micrometer screw. Second, angular deviations between the measurement points were analyzed based on 3D scans. Possible effects were investigated by use of Kruskal-Wallis test and the Steel-Dwass method.
Results: Sufficient shape accuracy was given for artificial teeth with wall thicknesses of 0.5 mm or greater. Largest distance deviations were observed for 0.3 mm wall thickness, in particular DB-BB showed median deviation above 56.2 µm, which was significantly larger than those found for the other test groups ranging from 7.4 µm to 9.5 µm (p<0.05). In most cases, angular deviations were also largest for teeth with 0.3 mm wall thickness (11.6°) and remained below 5.0° for the other test groups.
Conclusions: Sufficient accuracy was given for artificial teeth with at least 0.5 mm wall thickness.
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