IADR Abstract Archives
The Accuracy of 3D Printed Crowns Using a DLP Printer
Objectives: Digital light processing (DLP) printers are increasingly used in dentistry. However, there is a lack of consensus on a recommended build angle and the effect of varying positions in the build platform has yet to be determined. This study investigated the effect of these two parameters on the accuracy of 3D printed crowns.
Methods: A master model of a lower right first molar was scanned using an intra oral scanner (3Shape Trios® 4) and digital crown was designed. Nine crowns in nine standardized positions in the build platform were printed using NextDentTM 5100 DLP printer at 90°, 120°, 135°, 150°, 180°, 210°, 225°, 240° and 270° build angles. The experiment was repeated three times per build angle. Printed crowns were scanned and their Standard Tessellation Language files compared with the original file using Geomagic® Control XTM. Root mean square (RMS) analysis was done to determine overall deviation values. 2D Compare and simulated coordinate measuring machine (CMM) measurements were used to determine specific positive and negative deviation values at selected points. Results were analysed using two-way and one-way ANOVA. Statistical significance was set at p<0.05.
Results: Lowest RMS values were recorded at 210 degrees build angle (0.0271±0.0022mm) and C2 position (0.0294±0.0046mm) in the build platform. Simulated CMM analysis showed significant differences between accuracy of crowns at external finish lines across different build angles (p<.0001). Crowns oriented towards 90 degrees (152±46.6μm) and 270 degrees (209±25.7μm) exhibited the greatest amount of deviations at mesial and distal internal axial surfaces. The greatest amount of deviation at the external finish lines occurred at 90 and 270 degree build angles. These values ranged from -81.9 to 79.9μm.
Conclusions: The recommended build angles for printing a single molar crown are 150 and 210 degrees. Position in build platform did not affect the accuracy of crowns significantly at external finish lines.
Methods: A master model of a lower right first molar was scanned using an intra oral scanner (3Shape Trios® 4) and digital crown was designed. Nine crowns in nine standardized positions in the build platform were printed using NextDentTM 5100 DLP printer at 90°, 120°, 135°, 150°, 180°, 210°, 225°, 240° and 270° build angles. The experiment was repeated three times per build angle. Printed crowns were scanned and their Standard Tessellation Language files compared with the original file using Geomagic® Control XTM. Root mean square (RMS) analysis was done to determine overall deviation values. 2D Compare and simulated coordinate measuring machine (CMM) measurements were used to determine specific positive and negative deviation values at selected points. Results were analysed using two-way and one-way ANOVA. Statistical significance was set at p<0.05.
Results: Lowest RMS values were recorded at 210 degrees build angle (0.0271±0.0022mm) and C2 position (0.0294±0.0046mm) in the build platform. Simulated CMM analysis showed significant differences between accuracy of crowns at external finish lines across different build angles (p<.0001). Crowns oriented towards 90 degrees (152±46.6μm) and 270 degrees (209±25.7μm) exhibited the greatest amount of deviations at mesial and distal internal axial surfaces. The greatest amount of deviation at the external finish lines occurred at 90 and 270 degree build angles. These values ranged from -81.9 to 79.9μm.
Conclusions: The recommended build angles for printing a single molar crown are 150 and 210 degrees. Position in build platform did not affect the accuracy of crowns significantly at external finish lines.