Abstract
The information in the literature on the effect of printing layer thickness on interim 3D-printed crowns is limited. In the present study, the effect of layer thickness on the trueness and margin quality of 3D-printed composite resin crowns was investigated and compared with milled crowns. The crowns were printed in 3 different layer thicknesses (20, 50, and 100 μm) by using a hybrid resin based on acrylic esters with inorganic microfillers or milled from polymethylmethacrylate (PMMA) discs and digitized with an intraoral scanner (test scans). The compare tool of the 3D analysis software was used to superimpose the test scans and the computer-aided design file by using the manual alignment tool and to virtually separate the surfaces. Deviations at different surfaces on crowns were calculated by using root mean square (RMS). Margin quality of crowns was examined under a stereomicroscope and graded. The data were evaluated with one-way ANOVA and Tukey HSD tests. The layer thickness affected the trueness and margin quality of 3D-printed interim crowns. Milled crowns had higher trueness on intaglio and intaglio occlusal surfaces than 100 μm-layer thickness crowns. Milled crowns had the highest margin quality, while 20 μm and 100 μm layer thickness printed crowns had the lowest. The quality varied depending on the location of the margin.
Highlights
computer aided design-computer aided manufacturing (CAD-CAM) manufacturing can be subtractive [2] or additive, and the interest has recently shifted towards additive manufacturing technologies that are known as rapid prototyping or 3-dimensional
One-way analyzedby byusing usingthe theone-way one-way analysis variance (ANOVA) results of the root mean square (RMS) values of each surface are presented in Table 1, One-way ANOVA results of the RMS values of each surface are presented in Table and Figure 6 illustrates the RMS at each measured surface for control and different layer1, and Figure 6 illustrates the RMS at each measured surface for control and different thickness groups
The present study showed that 3D-printed interiminterim crowns,crowns, printed printed withthickness a layer thickness of μm, 20 orare
Summary
The introduction of digital technologies into dental practice has facilitated manufacturing, as computer aided design-computer aided manufacturing (CAD-CAM) enabled the fabrication of accurate definitive restorations [1]. CAD-CAM manufacturing can be subtractive (milling) [2] or additive, and the interest has recently shifted towards additive manufacturing technologies that are known as rapid prototyping or 3-dimensional (3D) printing [3,4,5]. Printing has certain advantages over milling as less waste material is produced, multiple products with more complex geometries can be fabricated, and less energy is consumed [14,15]. Due to an increased accuracy and speed, of 3D-printing has increased its popularity in the dental field [16]
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