Assessment of Compatibility between Various Intraoral Scanners and 3D Printers through an Accuracy Analysis of 3D Printed Models

Abstract

To assess the accuracy of various intraoral scanners (IOSs) and to investigate the existence of mutual compatibility that affects the accuracy between IOS and 3-dimensional (3D) printing using a scan quadrant model. For clinical implication, crown preparations and cavity design according to prosthetic diagnosis and treatment considerations must be acquired by a digital scanner. The selected typodont model was scanned using a reference scanner, from which reference (Ref) standard tessellation language (STL) data were created. Data obtained by scanning the typodont model with IOSs based on three different technologies were divided into three groups (CS3600, i500, and Trios3). Scanned data from the groups were divided into sub-groups of digital light processing (DLP), fused deposition modeling (FDM), and stereolithography apparatus (SLA), based on which 3D printed models (3DP) were fabricated. The 3DP dental models were scanned to obtain a total of 90 3DP STL datasets. The best-fit algorithm of 3D analysis software was used for teeth and arch measurements, while trueness was analyzed by calculating the average deviation among measured values based on superimposition of Ref and IOS and 3DP data. The differences between Ref and IOS (Ref-IOS), Ref and 3DP (Ref-IOS/3DP), and IOS and 3DP data (IOS-3DP) were compared and analyzed, while accuracy within each of the three main groups was assessed. For statistical analysis, the Kruskal-Wallis, Mann-Whitney U, and repeated measures ANOVA test were used (p < 0.05). The major finding is that the mutual relationships between IOSs and 3D printers vary depending on the combination. However, i500 intraoral scanner and DLP 3D printer was the combination that showed the best trueness value.

Keywords: 3-dimensional printer; dental computer aided manufacturing (CAD-CAM); intraoral scanner; quadrant model; trueness.

Figure 1

(A) 3-dimensional (3D) printed right maxillary quadrant Co-Cr typodont model, (B) Complete coverage crown preparation on maxillary canine (MxC#13), (C) Occlusal inlay preparation on maxillary first premolar (MxFPM#14), (D) Mesio-occlusal inlay preparation on maxillary first molar (MxFM#16).

Figure 2

Three main groups (Ref-IOS, Ref-IOS/3D printed models (3DP), and IOS-3DP data) of the superimposed data read workflow diagram. (* Each printed model was scanned with a tabletop scanner to obtain standard tessellation language (STL) data).

Figure 3

Representative deviations of superimposition using a surface matching software on the 3D digital model. Range of deviation was color coded from −100 (blue) to +100 µm (red). (A) superimposition between Ref-IOS data. (B) superimposition between Ref-IOS/3DP data. (C) superimposition between IOS-3DP data.

Figure 4

Surface characteristics of three different types of ((A) digital light processing (DLP), (B) fused deposition modeling (FDM), and (C) stereolithography apparatus (SLA)) 3D printed models.

Figure 5

(A) The teeth #13 (MxC), (B) #14 (MxFPM), and (C) #16 (MxFM). The numbers of per unit area compared in terms of the density and geometry of the triangle polygons for qualitative evaluation of each intraoral scanners (IOSs) and 3DP STL data.

Figure 6

(A) DLP, (B) FDM, and (C) SLA each of the 3D printed models-SEM images at the three type surface characteristics of the models in the layer thickness density and shape by layer technique for qualitative evaluation (original magnification 30×).