The Effect of Build Orientation on the Dimensional Accuracy of 3D-Printed Mandibular Complete Dentures Manufactured with a Multijet 3D Printer

Purpose To compare the dimensional accuracy of 3D-printed mandibular complete dentures with different build orientations. Material and Methods A mandibular complete denture was digitized as a virtual reference file. The reference file was 3D-printed at the 0 degrees, 45 degrees, and 90 degrees build orientations with a MultiJet 3D printer (Projet MJP 3600 Dental, 3D systems, Rock Hill, SC). A total of 27 complete dentures were 3D-printed with 9 samples for each orientation. All printed dentures were digitized and separated into teeth, denture extension and intaglio test surfaces. The dimensional accuracy (in root mean square, RMS) was evaluated by comparing whole denture and 3 test surfaces with the reference file. One-way analysis of variance (ANOVA) and a Post-Hoc all pairs Bonferroni test were used to determine statistical differences (alpha = 0.05). Results For the dimensional accuracy on whole denture, the 45 degrees build orientation group showed the smallest RMS (0.170 +/- 0.043 mm) than those of the 0 degrees build orientation group (0.185 +/- 0.060 mm, p < 0.001) and 90 degrees build orientation group (0.183 +/- 0.044 mm, p < 0.001). For the dimensional accuracy on the teeth, denture extension and intaglio test surfaces, the 45 degrees build orientation group also show the smallest RMS values (0.140 +/- 0.044 mm at teeth surface, 0.176 +/- 0.058 mm at denture extension and 0.207 +/- 0.006 mm at intaglio surface). The 0 degrees and 90 degrees build orientation groups had similar accuracy at the teeth (0.149 +/- 0.056 mm versus 0.154 +/- 0.056 mm, p = 0.164) and denture extension surfaces (0.200 +/- 0.025 mm vs 0.196 +/- 0.013 mm, p = 1.000). However, 0 degrees build orientation group (0.228 +/- 0.010 mm) has significantly higher RMS values then those of 90 degrees build orientation group (0.218 +/- 0.057 mm) in the intaglio surface (p = 0.032). The teeth surfaces were most accurate in each build orientation groups, while the intaglio surfaces were least accurate. Conclusions The build orientation affected the dimensional accuracy of 3D-printed mandibular complete dentures, and the 45 degrees build orientation resulted in the most accurate 3D-printed denture from a MultiJet 3D printer.