Flexural Properties and Hardness of CAD‐CAM Denture Base Materials
Shaimaa M. Fouda, Mohammed M. Gad, Reem Abualsaud, Passent Ellakany, Hamad S. AlRumaih, Soban Q. Khan, Sultan Akhtar, Faisal D. al‐Qarni, Fahad A. Al‐Harbi
Abstract
PURPOSE: To compare flexural strength, elastic modulus, and surface hardness of computer aided design and computer aided manufacturing CAD-CAM milled, 3D-printed, and heat-polymerized denture base resins. MATERIALS AND METHODS: A total of 120 specimens were fabricated from heat-polymerized acrylic resin (HP), milled resin (Avadent and IvoCad), and 3D-printed resin (ASIGA, FormLabs, and NextDent). The specimens were divided into 6 groups according to the type of denture base material (n = 20/material) (10/flexural properties and 10/hardness). Flexural strength and elastic modulus of the specimens were evaluated by 3-point bending test and surface hardness by Vickers hardness test. To test flexural properties, the specimens were fabricated according to ISO 20795-1:2013 standards (64 × 10 × 3.3 ± 0.2 mm). The dimensions for hardness test were 15 × 10 × 2.5 ± 0.2 mm. Scanning electron microscope was used to evaluate the surface morphology of the fractured specimens. The means and standard deviations were calculated, followed by one-way ANOVA and Tukey post-hoc test (α = 0.05). RESULTS: Milled resins showed significantly higher values for flexural strength, elastic modulus, and surface hardness, followed by HP and then 3D-printed resins (p < 0.001). Within milled groups, flexural strength of AvaDent was significantly higher than IvoCad (p < 0.001), while elastic modulus and hardness didn't show significant difference. Within 3D-printed resins, ASIGA showed the highest flexural strength and elastic modulus, insignificantly with FormLabs (p = 0.595) and significantly with NextDent (p = 0.008). ASIGA also showed significantly the highest hardness among the 3D-printed groups. No significant difference was found between FormLabs and NextDent in flexural strength (p = 0.357), elastic modulus (p = 1.00), or surface hardness (p = 0.987). CONCLUSION: CAD-CAM milled resins had greater flexural properties and hardness compared to heat-polymerized acrylic resin and 3D-printed resins. Although 3D-printed samples showed the lowest values of tested properties, the flexural strength and modulus were above clinically acceptable values.