3D-printed Dentures Deviate From the CAD File
Objectives: 3D printing may offer an affordable method for producing dentures. The clinical fit of the denture may be affected by distortion introduced during manufacturing. The diamond-pixel arrangement commonly used in DLP printers is not equally scaled in X and Y. This study investigated the dimensional accuracy of 3D printed dentures orientated differently along the X and Y axis against the original CAD file.
Methods: CAD designed upper and lower dentures were printed using E-Denture 3D+ resin in an Envisiontec Micro Plus XL 3D printer (both Envisiontec, MI, USA) at two different orientations: a) occlusal plane aligned along the X axis, b) occlusal plane aligned along the Y axis. The prints were cleaned and cured according to manufacturer’s recommendations. The fit surface of each denture was scanned using a laboratory scanner (Rexcan DS2, Solutionix, Seoul, Korea) with corresponding software (EzScan 7, Solutionix, Seoul, Korea). Each scanned surface was aligned to the original CAD file using custom software (Leeds Digital Dentistry, Leeds, UK). Custom software was used to uniformly crop all scan surfaces against the CAD files. Mesh distance deviations were measured.
Results: The unsigned mean distance deviation was significantly greater in the upper denture than the lower denture (U: 0.129±0.013mm; L: 0.048±0.010mm; mean difference: 0.081, 95% CI: 0.072-0.089). The proportion of fit which deviated beyond 0.1mm from the CAD file showed the same trend (mean difference (U-L): 33.0%, 95% CI: 11.6-44.6%). However, the print orientation did not affect the unsigned mean distance deviation (mean difference (X-Y): 0.042, 95% CI: -0.090 – 0.173) or the proportion of fit (mean difference: 0.1%, 95% CI: -0.031 – 0.033%).
Conclusions: X-Y orientation on the build plate did not result in significant distortion in print dimensions. The lower dentures printed with greater trueness and precision than the upper. The geometry of the print object may impact on the accuracy of the print.