Dimensional Accuracy of Dental Models for Three-Unit Prostheses Fabricated by Various 3D Printing Technologies

Abstract

Previous studies on accuracy of three-dimensional (3D) printed model focused on full arch measurements at few points. The aim of this study was to examine the dimensional accuracy of 3D-printed models which were teeth-prepped for three-unit fixed prostheses, especially at margin and proximal contact areas. The prepped dental model was scanned with a desktop scanner. Using this reference file, test models were fabricated by digital light processing (DLP), Multi-Jet printing (MJP), and stereo-lithography apparatus (SLA) techniques. We calculated the accuracy (trueness and precision) of 3D-printed models on 3D planes, and deviations of each measured points at buccolingual and mesiodistal planes. We also analyzed the surface roughness of resin printed models. For overall 3D analysis, MJP showed significantly higher accuracy (trueness) than DLP and SLA techniques; however, there was not any statistically significant difference on precision. For deviations on margins of molar tooth and distance to proximal contact, MJP showed significantly accurate results; however, for a premolar tooth, there was no significant difference between the groups. 3D color maps of printed models showed contraction buccolingually, and surface roughness of the models fabricated by MJP technique was observed as the lowest. The accuracy of the 3D-printed resin models by DLP, MJP, and SLA techniques showed a clinically acceptable range to use as a working model for manufacturing dental prostheses.

Keywords: 3D printing; digital light processing (DLP); dimensional accuracy; multi-jet printing (MJP); stereo-lithography apparatus (SLA).

Figure 1

Flow chart of this study. 3D, three-dimensional; DLP, digital light processing; MJP, Multi-Jet printing; SLA, stereo-lithography apparatus.

Figure 2

3D-printed resin models (n = 36) of this study. First row; DLP models, second row; MJP models; third row; SLA models.

Figure 3

Four landmarks for measurement of trueness on 3D-printed models with the reference file. (a) molar tooth at buccolingual section. (b) Premolar tooth at buccolingual section. (c) Proximal contact to approximate tooth. (d) Molar and premolar teeth at mesiodistal section.

Figure 4

Color maps of 3D model superimpositions of each printed test model STL file with the original reference file. Table 50. μm expressing green colors, and max/min critical range at ±500 μm representing dark red or blue colors. The Scheme 0. to 0.5 mm. (a) DLP cast. (b) MJP cast. (c) SLA cast.

Figure 5

Measurements of deviations in two-dimensional (2D) planes. (a) Marginal deviations of molar teeth at a buccolingual plane. (b) Marginal deviations of premolar teeth at a buccolingual plane. (c) Deviations at proximal contact to approximate tooth. (d) Marginal deviations of molar and premolar teeth at a mesiodistal plane.