Influence of Post-Printing Polymerization Time on Flexural Strength and Microhardness of 3D Printed Resin Composite
Source abstract
Abstract
Background: The adoption of 3D printing in restorative dentistry is increasing, with the post-curing duration of a material being identified as a key determinant of its performance. This study evaluated the effect of the post-polymerization time on the flexural strength (FS) and Vickers microhardness (VHN) of a 3D-printed composite. Methods: Specimens of Formlabs Permanent Crown Resin were 3D printed and divided into four groups according to their post-curing time: no post-curing time and 20, 40, and 60 min post-curing time. Flexural strength testing was carried out using a three-point test of 40 bar-shaped specimens (n = 10/group), followed by fractography observations under a scanning electron microscope (SEM). Vicker microhardness testing was also conducted with 40 disk-shaped specimens (n = 10/group). The inorganic filler content was measured using the ash method, and the filler morphology was characterized under an SEM. Statistical analyses were performed using adjusted ANOVA and regression tests. Results: The highest median FS values were observed at 40 min post-curing (133.07 MPa), with significant differences across all groups (p < 0.0001). The highest median VHN values were found at 40 min post-curing (32.09 VHN), with significant differences between groups (p < 0.0001). A significant positive correlation (rho = 0.7488; p < 0.0001) was found between the flexural strength and Vickers hardness with changing post-curing durations. The 3D resin composite had an average filler content of 66.82% based on weight. Conclusions: With the limitation of the current in vitro setup, a post-polymerization time of 40 min was shown to lead to the best material performance. The post-printing polymerization time significantly affects the Vickers hardness and FS of 3D Formlabs Permanent Crown Resin. Further research should explore the effects of different resin compositions, clinical conditions, and curing protocols to enhance the general applicability of these findings. Clinical implications: Extending the post-printing polymerization time does not inherently result in improved material properties. A considered adjustment of the post-curing time can significantly impact the mechanical properties of a 3D-printed composite.
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Research context
OpenAlex topics: Additive Manufacturing and 3D Printing Technologies · Dental materials and restorations · Photopolymerization techniques and applications
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
Department of Restorative Dental Science, College of Dentistry, King Saud University, Riyadh 11362, Saudi Arabia
Department of Conservative Dentistry, College of Dentistry, Aljouf University, Sakaka 72388, Saudi Arabia
Periodontics and Community Dentistry, College of Dentistry, King Saud University, Riyadh 11362, Saudi Arabia
Oral Health Policy and Epidemiology, Harvard School of Dental Medicine, Boston, MA 02115, USA
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