IADR Abstract Archives
UV-curing Conditions Affect Physical Properties of 3D-Printed Denture Base Resins
Objectives: To investigate the effects of UV curing on the physical properties (degree of conversion, water sorption, and solubility) of 3D-printed denture resins.
Methods: Disk specimens (50mm diameter, 1.3mm thick, n=5/group) were prepared by 3D-printing from Denture Base II (DENTCA) using Freeform PRO2 3D printer (ASIGA) for water sorption/solubility analysis and smaller discs (10 mm diameter, 2mm thick, n=5/group) were prepared the same way for degree of conversion (DC). All samples were cured in a home-made UV curing oven equipped with RX StarFire 150 2W variable output LED UV light (Phoseon Technology). UV intensity (irradiance) was measured by PowerMax radiometer (Coherent). Each group were cured under 0, 30, 70, 120, and 200 mW/cm2 for 10 min on each side (total 20 min), and polished with 600 grit SiC abrasive paper. For water sorption/solubility analysis, specimens were weighed with a digital balance to 0.00001g according to ISO standard 4049, then stored in deionized water under 37oC for 1 week. Samples were then desiccated and weighed until a steady weight was recorded. DC of the discs cured under different UV intensity (irradiance) was measured using Nexus 670 FT-NIR (Thermo-Nicolet). DC was calculated using the absorbance peak areas of polymer (Ap) and monomer (Am) around 6163 cm−1 as follows:
DC(%)=(1–Ap/Am)×100.
Results: As shown in Figure 1 and Figure 2, degree of conversion increased significantly from 0 to 30 mW/cm2(p<0.05), but no significant increase at UV intensity ≥70 mW/cm2. There was no significant difference in water sorption among the groups; however, solubility decreased significantly from 0 to 30 mW/cm2 but no further change at higher UV intensity.
Conclusions: UV intensity (irradiance) for post-printing cure has significant effect on the physical properties of 3D-printed denture base resin but such effects diminish as long as the UV intensity ≥70 mW/cm2.
Methods: Disk specimens (50mm diameter, 1.3mm thick, n=5/group) were prepared by 3D-printing from Denture Base II (DENTCA) using Freeform PRO2 3D printer (ASIGA) for water sorption/solubility analysis and smaller discs (10 mm diameter, 2mm thick, n=5/group) were prepared the same way for degree of conversion (DC). All samples were cured in a home-made UV curing oven equipped with RX StarFire 150 2W variable output LED UV light (Phoseon Technology). UV intensity (irradiance) was measured by PowerMax radiometer (Coherent). Each group were cured under 0, 30, 70, 120, and 200 mW/cm2 for 10 min on each side (total 20 min), and polished with 600 grit SiC abrasive paper. For water sorption/solubility analysis, specimens were weighed with a digital balance to 0.00001g according to ISO standard 4049, then stored in deionized water under 37oC for 1 week. Samples were then desiccated and weighed until a steady weight was recorded. DC of the discs cured under different UV intensity (irradiance) was measured using Nexus 670 FT-NIR (Thermo-Nicolet). DC was calculated using the absorbance peak areas of polymer (Ap) and monomer (Am) around 6163 cm−1 as follows:
DC(%)=(1–Ap/Am)×100.
Results: As shown in Figure 1 and Figure 2, degree of conversion increased significantly from 0 to 30 mW/cm2(p<0.05), but no significant increase at UV intensity ≥70 mW/cm2. There was no significant difference in water sorption among the groups; however, solubility decreased significantly from 0 to 30 mW/cm2 but no further change at higher UV intensity.
Conclusions: UV intensity (irradiance) for post-printing cure has significant effect on the physical properties of 3D-printed denture base resin but such effects diminish as long as the UV intensity ≥70 mW/cm2.
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