Purpose The aim of this paper is to examine the effects of light controlling system that combined high refractive particles (n-TiO2 [titanium dioxide – TiO2]) and tartrazine lake dye (TL dye) on thickness, flexural strength, flexural modulus and surface details of the 3D-printed resin. Design/methodology/approach Influences of different concentrations of n-TiO2 and TL dye in light-cured resin formulations for 3D printing (3DP) application were evaluated, including curing thickness, flexural strength and surface details under scanning electron microscopy. Findings The polymerization thickness of samples containing both n-TiO2 and TL dye was lower compared to samples with TL dye solely. Samples containing more n-TiO2 and more TL dye exhibited lower flexural strength and modulus. Ramp models showed that for samples containing 1 per cent TL dye, when their n-TiO2 content increased from 1 to 5 per cent, surface laminate structures became sharper. However, when the TL dye content doubled to 2 per cent, the surface laminate structures were indefinite compared to 1 per cent TL dye-containing counterparts. Originality value In visible-light 3DP, light controlling system in cooperate dye with high refractive particles provides better energy distribution and scattering control. High refractive particles, dyes and light exposure time had influenced the surface resolution and mechanical properties of the 3DP products.

No abstract

No abstract

The use of multi-resins entails certain challenges due to inter-stain in the intermediate layer of cured resins and misalignment caused by the use of multi-light sources or vat switching. This study proposes a new mechanism for a multi-resin three-dimensional printer that can fabricate physical models consisting of different resins without misalignment using the bottom-up method with a digital projector and a clean modulus that can avoid inter-staining. Experimental results show that the proposed C-arm design offers self-alignment when the platform is switched or during cleaning. The proposed clean modulus can also prevent inter-staining, thus producing a clear boundary layer. The linear and angular dimensions are respectively accurate within 20 µm and 0.2 o .

Purpose This study aims to compare the marginal fit, flexural strength and hardness for a ceramic premolar that is constructed using dental computer aided machining (CAM) and three-dimensional slurry printing (3DSP). Design/methodology/approach Dental CAM and 3DSP are used to fabricate a premolar model. To reduce the fabrication time for 3DSP, a new composition of solvent-free slurry is proposed. Before it is fabricated, the dimensions of the green body for the premolar model are enlarged to account for the shrinkage ratio. A two-stage sintering process ensures accurate final dimensions for the premolar model. The surface morphology of the green body and the sintered premolars that are produced using the two methods is then determined using scanning electronic microscopy. The sintered premolars are seated on a stone model to determine the marginal gap using an optical microscope. The hardness and the flexural strength are also measured for the purpose of comparison. Findings The developed solvent-free slurry for 3DSP can be used to produce a premolar green body without micro-cracks or delamination. The maximal marginal gap for the sintered premolar parts that are constructed using the green bodies from dental CAM is 98.9 µm and that from 3DSP is 72 µm. Both methods produce a highly dense zirconia premolar using the same sintering conditions. The hardness value for the dental CAM group is 1238.8 HV, which is slightly higher than that for the 3DSP group (1189.4 HV) because there is a difference in the pre-processing of the initial ceramic materials. However, the flexural strength for 3DSP is 716.76 MPa, which is less than the requirement for clinical use. Originality/value This study verifies that 3DSP can be used to fabricate a zirconia dental restoration device that is as good as the one that is produced using the dental CAM system and which has a marginal gap that is smaller than the threshold value. The resulting premolar restoration devices that are produced by sintering the green bodies that are produced using 3DSP and dental CAM under the same conditions have a similar hardness value, which is four times greater than that of enamel. The flexural strength of 3DSP does not meet the requirement for clinical use.