Abstract
Background Recently, dentists can utilize three-dimensional printing technology in fabricating dental restoration. However, to date, there is a lack of evidence regarding the effect of printing layer thicknesses and postprinting on the mechanical properties of the 3D-printed temporary restorations with the additive manufacturing technique. So, this study evaluated the mechanical properties of a 3D-printed dental resin material with different printing layer thicknesses and postprinting methods. Methods 210 specimens of a temporary crown material (A2 EVERES TEMPORARY, SISMA, Italy) were 3D-printed with different printing layer thicknesses (25, 50, and 100 μm). Then, specimens were 3D-printed using DLP technology (EVERES ZERO, DLP 3D printer, SISMA, Italy) which received seven different treatment conditions after printing: water storage for 24 h or 1 month, light curing or heat curing for 5 or 15 minutes, and control. Flexural properties were evaluated using a three-point bending test on a universal testing machine (ISO standard 4049). The Vickers hardness test was used to evaluate the microhardness of the material system. The degree of conversion was measured using an FT-IR ATR spectrophotometer. Statistical analysis was performed using two-way analysis of variance (ANOVA) and Tukey's honestly significant difference (HSD) test (p ≤ 0.05). Results The 100 μm printing layer thickness had the highest flexural strength among the other thickness groups. As a combined effect printing thickness and postprinting conditions, the 100 μm with the dry storage group has the highest flexural strength among the tested groups (94.60 MPa). Thus, the group with 100 μm thickness that was heat cured for 5 minutes (HC 5 min 100 μm) has the highest VHN value (VHN = 17.95). Also, the highest mean DC% was reported by 50 μm layer thickness (42.84%).Conclusions The thickness of the 100 μm printing layer had the highest flexural strength compared to the 25 μm and 50 μm groups. Also, the postprinting treatment conditions influenced the flexural strength and hardness of the 3D-printed resin material.
Highlights
Three-dimensional (3D) printing has advanced rapidly in recent years, expanding its accuracy and reliability and making it highly attractive to the medical field. 3D printing has paved the way for new applications in various areas of health care, including medicine, dentistry, orthopedics, engineered tissue models, and medical devices [1,2,3]
The two-way analysis of variance (ANOVA) shows statistically significant differences among the groups (Fð6,189Þ = 23:49, p < 0:001). They indicate a significant influence of water storage, light curing, and heat curing on the flexural strength of the 3D-printed composite resin material
Our study focused on the use of different curing conditions to ensure the complete polymerization of the 3D resin material as this has been hypothesized to have an effect on the mechanical properties and degree of conversion of the tested material
Summary
Three-dimensional (3D) printing has advanced rapidly in recent years, expanding its accuracy and reliability and making it highly attractive to the medical field. 3D printing has paved the way for new applications in various areas of health care, including medicine, dentistry, orthopedics, engineered tissue models, and medical devices [1,2,3]. 3D printing has paved the way for new applications in various areas of health care, including medicine, dentistry, orthopedics, engineered tissue models, and medical devices [1,2,3]. This technology enables the rapid conversion of digital 3D models into physical objects by first producing a digital file in STL (standard triangulation language) format and 3D printing by joining, bonding, or polymerizing small volume elements [4]. This study evaluated the mechanical properties of a 3D-printed dental resin material with different printing layer thicknesses and postprinting methods. The postprinting treatment conditions influenced the flexural strength and hardness of the 3D-printed resin material
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