Strength and stiffness of interim materials and interim fixed dental prostheses when tested at different loading rates

• Published in: The Journal of prosthetic dentistry 2022-01, Vol.127 (1), p.161-167
• Main Authors: Lee, Joyce, Clark, Shawna R., Tantbirojn, Daranee, Korioth, Tom V.P., Hill, Anne E., Versluis, Antheunis
• Format: Article
• Language: English
• Subjects: Composite Resins; Dental Materials; Dental Stress Analysis; Denture, Partial, Temporary; Materials Testing; Pliability; Stress, Mechanical; Surface Properties
• ISSN: 0022-3913; 1097-6841
• DOI: 10.1016/j.prosdent.2020.10.008

How the loading rate might affect the mechanical properties of interim materials and interim fixed dental prostheses is unclear. The purpose of this in vitro study was to compare the material stiffness, material strength, and structural strength of interim 3-unit fixed dental prostheses fabricated from 3 interim materials when stressed at different loading rates. Bar-shaped specimens and anatomically correct interim 3-unit fixed dental prostheses with a modified-ridge lap pontic were fabricated from polyethyl methacrylate resin (Trim) and 2 bis-acrylic composite resins (TempSmart; Integrity) (n=10). Flexural modulus and strength of the bar specimens, representing material stiffness and strength, were determined with a 4-point bend test in a universal testing machine. The structural strength of the prosthesis was assessed from the failure load from a vertical force applied on the occlusal surface of the pontic. Three loading rates, 0.5, 5, or 10 mm/min, were evaluated. Results were statistically analyzed with 2-way analysis of variance and multiple comparisons (α=.05). Loading rate and material significantly affected flexural modulus, flexural strength, and structural strength (P