In vitro examination of fracture resistance of 3D-printed resin blocks in different diameters

Abstract

Objectives: The intraoral use of commercial printable polymers in dental patients is still a challenge due to the unknown physical properties of the materials. The present study aimed to comparably evaluate the maximum load and deflection values of three-dimensional-printed resin blocks in different diameters that can be used intraorally in dental patients. Material and Methods: Forty-five cylindrical resin blocks in diameters of 2 mm (Group 1, n = 15), 3 mm (Group 2, n = 15), and 4 mm (Group 3, n = 15) and lengths of 20 mm were designed and printed. The samples were placed in the universal testing device to conduct the 3-point bending test. According to the Shapiro–Wilk normality test results, Kruskal–Wallis and Mann–Whitney U tests were performed for the statistical analysis. The level of statistical significance was accepted as P < 0.05. Results: The values for the maximum load (N) and deflection (mm) in the study groups were 218.4 ± 31.9, 2.96 ± 0.86 in Group 3; 77.05 ± 61.5, 3.91 ± 0.92 in Group 2; and 19.67 ± 2.63, 4.06 ± 1.02 in Group 1, respectively. The mean values of maximum load for Group 3 were superior to Group 2 (P = 0.020) and Group 1 (P = 0.00). Group 2 revealed higher maximum load results than Group 1 (P = 0.003). The mean values of maximum deflection in Group 3 were lower compared to Group 2 (P = 0.014) and Group 1 (P = 005). Conclusion: The results of this in vitro study encourage the use of resin-printed intraoral appliances in place of conventional treatment modalities.

Comparison of the Flexural Strength of Three Different Aged and Nonaged 3D-Printed Permanent Crown Resins

“…25,26 The aged specimens in the present study were thermocycled for 10,000 cycles, simulating 2 years of intraoral use. 15 Gad et al 27 investigated the strength properties of 3D-printed denture base resin and indicated that thermocycling significantly lowered the flexural strength. In accordance with their study, the present results showed that thermocycling caused poorer flexural strength in all three tested resin groups when compared to the nonthermocycled samples.…”

“…Physiologic values of occlusal forces during mastication vary between 10 and 120 N, and a dental appliance should resist these forces in the intraoral environment. 15 For dentists to choose the appropriate 3D-printing material, the mechanical properties of these materials and their behavior in intraoral conditions must be known. As well as the type of 3D printing technique, several additional factors affect the physical and mechanical behavior of the printed product, such as the material composition, printing orientation, postcuring time, layer thickness, and aging.…”