Comparison of prosthetic models produced by traditional and additive manufacturing methods.
OBJECTIVE
The purpose of this study was to verify the clinical-feasibility of additive manufacturing by comparing the accuracy of four different manufacturing methods for metal coping: the conventional lost wax technique (CLWT); subtractive methods with wax blank milling (WBM); and two additive methods, multi jet modeling (MJM), and micro-stereolithography (Micro-SLA).


METHODS
Thirty study models were created using an acrylic model with the maxillary upper right canine, first premolar, and first molar teeth. Based on the scan files from a non-contact blue light scanner (Identica; Medit Co. Ltd., Seoul, Korea), thirty cores were produced using the WBM, MJM, and Micro-SLA methods, respectively, and another thirty frameworks were produced using the CLWT method. To measure the marginal and internal gap, the silicone replica method was adopted, and the silicone images obtained were evaluated using a digital microscope (KH-7700; Hirox, Tokyo, Japan) at 140X magnification. Analyses were performed using two-way analysis of variance (ANOVA) and Tukey post hoc test (α=.05).


RESULTS
The mean marginal gaps and internal gaps showed significant differences according to tooth type (P<.001 and P<.001, respectively) and manufacturing method (P<.037 and P<.001, respectively). Micro-SLA did not show any significant difference from CLWT regarding mean marginal gap compared to the WBM and MJM methods.


CONCLUSIONS
The mean values of gaps resulting from the four different manufacturing methods were within a clinically allowable range, and, thus, the clinical use of additive manufacturing methods is acceptable as an alternative to the traditional lost wax-technique and subtractive manufacturing.
Department of Dental Laboratory, Science and Engineering, College of Health Science, Korea University, Republic of Korea.
Jin-Young
JY
Park
Department of Dental Laboratory, Science and Engineering, College of Health Science, Korea University, Republic of Korea. ; Department of Public Health Sciences, Graduate Shchool & BK21+Program in Public Health Sciences, Korea University, Republic of Korea.
Hae-Young
HY
Kim
Department of Dental Laboratory, Science and Engineering, College of Health Science, Korea University, Republic of Korea.
Ji-Hwan
JH
Kim
Department of Dental Laboratory, Science and Engineering, College of Health Science, Korea University, Republic of Korea.
Jae-Hong
JH
Kim
Department of Dental Laboratory, Science and Engineering, College of Health Science, Korea University, Republic of Korea.
Woong-Chul
WC
Kim
Additive manufacturing; Internal gap; Marginal gap; Micro-SLA; Multi Jet Modeling; Subtractive manufacturing