Effect of uniaxial bending methods on the flexural strength and Weibull analysis of heat-polymerized, CAD/CAM milled, and 3D-printed denture base resins

Abdulaziz Alhotan; Hanan Al-Johani; Ahmed Altarazi; Abdullah Alshamrani; Ahmed Mahmoud Fouda

doi:10.1016/j.dental.2024.12.015

Effect of uniaxial bending methods on the flexural strength and Weibull analysis of heat-polymerized, CAD/CAM milled, and 3D-printed denture base resins

Dent Mater. 2025 Jan 6:S0109-5641(24)00369-5. doi: 10.1016/j.dental.2024.12.015. Online ahead of print.

Authors

Abdulaziz Alhotan¹, Hanan Al-Johani², Ahmed Altarazi³, Abdullah Alshamrani¹, Ahmed Mahmoud Fouda⁴

Affiliations

¹ Department of Dental Health, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia.
² Department of Restorative Dentistry, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia. Electronic address: hamaljuhani1@kau.edu.sa.
³ Department of Restorative Dentistry, College of Dentistry, Taibah University, Madinah, Saudi Arabia.
⁴ Department of Oral Technology, Medical Faculty, University Hospital Bonn, Bonn, North Rhine-Westphalia, Germany; Department of Fixed Prosthodontics, Faculty of Dentistry, Suez Canal University, Ismailia, Egypt.

PMID: 39765363
DOI: 10.1016/j.dental.2024.12.015

Abstract

Objectives: To compare the flexural strength and modulus of denture base resins manufactured by conventional methods, 3-dimensional (3D) printing, and computer-aided design and computer-aided manufacturing (CAD/CAM) milling using 3-point bending (3PB) and 4-point bending (4PB) methods after simulated aging.

Methods: Ninety bars (64 ×10 ×3.3 mm) were prepared from heat-polymerized (Lucitone-199), CAD/CAM milled (G-CAM), and 3D-printed (Denturetec) denture base resins (n = 30 per material). After 10,000 thermal cycles, specimens were subjected to either 3-point bending (3PB) or 4-point bending (4PB) (n = 15 per method) to measure the flexural strength (σ_3PB and σ_4PB) and elastic modulus (E_3PB and E_4PB) using a universal testing machine. Weibull analysis was performed to evaluate the reliability (m) and characteristic strength (σ₀) as a function of 3PB and 4PB. Fractographic analysis was conducted using scanning electron microscopy (SEM). Data were analysed using 2-way ANOVA followed by Tukey post hoc and Student t-tests (α=.05).

Results: Significant effects of material type and uniaxial bending method on flexural strength and modulus were found (P < .001). Irrespective of the flexural strength measurement approach, CAD/CAM milled resins exhibited significantly higher flexural strength in both methods (σ_3PB=125.6 ± 5.2 MPa, σ_4PB=110.5 ± 4.5 MPa) and elastic modulus (E_3PB=2400 ± 120 MPa and E_4PB=2800 ± 150 MPa) compared to 3D-printed and heat-polymerized resins. Irrespective of the denture base resin manufacturing method, σ_3PB was significantly higher than σ_4PB whereas E_4PB was significantly higher than E_3PB (P < .001). Weibull analysis exhibited highest reliability for CAD/CAM resins (m=25.24 - 43.83). Considerable microscopic differences were detected.

Significance: CAD/CAM milled denture base resins exhibited superior flexural properties compared with 3D-printed and heat-polymerized resins.

Keywords: 3D printing; CAD/CAM; Denture base resins; Flexural strength; Reliability.