Influence of the base design on the accuracy of additive manufac tured casts measured using a coordinate measuring machine.

PURPOSE To measure the accuracy of the additively manufactured casts with 3 base designs: solid, honeycomb-structure, and hollowed bases. METHODS A virtual cast was used to create different base designs: solid (S Group), honeycomb-structure (HC group), and hollowed (H group). Three standard tessellation language files were used to fabricate the specimens using a material jetting printer (J720 Dental; Stratasys) and a resin (VeroDent MED670; Stratasys) (n=15). A coordinate measuring machine was selected to measure the linear and 3D discrepancies between the virtual cast and each specimen. Shapiro-Wilk test revealed that all the data was not normally distributed (P<.05). Kruskal Wallis and Mann Whitney U tests were used (α=.05). RESULTS The S group obtained a median ±interquartile range 3D discrepancy of 53.00 ±73.25 µm, the HC group of 58.00 ±67.25 µm, and the H group of 34.00 ±45.00 µm. Significant differences were found in the x- (P<.001), y- (P<.001), and z-axes (P<.001), and 3D discrepancies among the groups (P<.001). Significant differences were found between the S and H groups (P=.002) and HC and H groups (P<.001) on the x-axis; S and H groups (P<.001) and HC and H groups (P<.001) on the y-axis; S and H groups (P<.001) and HC and H groups (P<.001) on the z-axis; and S and H groups (P<.001) and HC and H groups (P<.001) on the 3D discrepancy. CONCLUSIONS The base designs influenced on the accuracy of the casts but all the specimens obtained a clinically acceptable manufacturing range. The H group obtained the highest accuracy.