IADR Abstract Archives
UV-curing conditions affect Mechanical Properties of 3D-Printed Denture Base Resin
Objectives: To investigate the effects of UV curing conditions and wash solvents on the mechanical properties of 3D-printed denture base materials.
Methods: Rectangular bar specimens (2x2x25 mm, n=12 per group) were prepared by 3D printing of Dentca Denture Base II (DENTCA) on Freeform PRO2 3D printer (ASIGA). Half of the bars were rinsed with isopropanol (as suggested by manufacturer), the other half with ethyl acetate. Samples were cured in a home-made UV curing oven equipped with a RX StarFire 150 2W variable output LED UV light (Phoseon Technology). UV intensity was measured by PowerMax radiometer (Coherent). Each group (n=12) were cured under 0 (control), 30, 70, 120, 150, 200, and 300 mW/cm2 for 10 or 20 minutes on each side (total 20 or 40 min), polished with 600 grit SiC abrasive paper, stored in deionized water under 37oC for 24 hours or 3 months before testing. Flexural strength and flexural modulus of bar specimens were tested on 3-point-bending device on Instron 5566 testing machine with crosshead speed of 1.0 mm/min.
Results: The flexural strengths are shown in Figure 1 (a, b) and flexural moduli are shown in Figure 2 (a,b). In general, the mechanical properties increase significantly with the increase of UV intensity but level off after 150 mW/cm2. Under 30 mW/cm2, the specimens rinsed with ethyl acetate show higher strength than those rinsed with isopropanol. There is no difference in mechanical properties between total curing time of 20 and 40 min for all groups with intensity ≥ 70 mW/cm2.
Conclusions: UV intensity and rinse solvent have significant effects on the mechanical properties of 3D-printed denture base materials. It is recommended that 3D-printed denture base be rinsed with ethyl acetate and UV cured with intensity ≥ 150 mW/cm2 for 10 min each side.
Methods: Rectangular bar specimens (2x2x25 mm, n=12 per group) were prepared by 3D printing of Dentca Denture Base II (DENTCA) on Freeform PRO2 3D printer (ASIGA). Half of the bars were rinsed with isopropanol (as suggested by manufacturer), the other half with ethyl acetate. Samples were cured in a home-made UV curing oven equipped with a RX StarFire 150 2W variable output LED UV light (Phoseon Technology). UV intensity was measured by PowerMax radiometer (Coherent). Each group (n=12) were cured under 0 (control), 30, 70, 120, 150, 200, and 300 mW/cm2 for 10 or 20 minutes on each side (total 20 or 40 min), polished with 600 grit SiC abrasive paper, stored in deionized water under 37oC for 24 hours or 3 months before testing. Flexural strength and flexural modulus of bar specimens were tested on 3-point-bending device on Instron 5566 testing machine with crosshead speed of 1.0 mm/min.
Results: The flexural strengths are shown in Figure 1 (a, b) and flexural moduli are shown in Figure 2 (a,b). In general, the mechanical properties increase significantly with the increase of UV intensity but level off after 150 mW/cm2. Under 30 mW/cm2, the specimens rinsed with ethyl acetate show higher strength than those rinsed with isopropanol. There is no difference in mechanical properties between total curing time of 20 and 40 min for all groups with intensity ≥ 70 mW/cm2.
Conclusions: UV intensity and rinse solvent have significant effects on the mechanical properties of 3D-printed denture base materials. It is recommended that 3D-printed denture base be rinsed with ethyl acetate and UV cured with intensity ≥ 150 mW/cm2 for 10 min each side.
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