Effect of storage and aging conditions on the flexural strength and flexural modulus of CAD/CAM materials

Abstract

Computer-aided design/computer-aided manufacturing (CAD/CAM) materials were submitted to thermocycling, to identify changes in mechanical behavior. Four CAD/CAM materials were divided in four subordinate groups (n=9): (1) dry out for 7 days, (2) distilled water at 37 o C for 7 days, (3) 60,000 thermocycles, and (4) 120,000 thermocycles. Following thermocycling, samples were submitted to three-point bending test. Two-way ANOVA and post-hoc Tukey's test were performed (α=0.05). The IPS e.max CAD had a flexural strength of 396±75 MPa and flexural modulus of 84±11 GPa, followed by Vita Enamic with values of 153±17 MPa and 28±5 GPa respectively. The flexural strength recorded for Lava Ultimate was 149±28 MPa and the flexural modulus was 12±3 GPa. Vitablocs Mark II had the lowest flexural strength values (125±10 MPa) and a flexural modulus of 49±15 GPa. Although polymer-based materials have similar mechanical properties compared to ceramics, they are affected by thermo cycling conditions.

Effect of Thermodynamic Aging on Colour Stability, Roughness and Flexural Strength of Two CAD/CAM Lithium Disilicate Glass Ceramics

“…This can be supported by the SEM images presented by Kang et al (2013) (1) , showing initially similar crystalline patterns in IPS e.max CAD and Rosetta SM, yet following crystallization; more dense crystalline microstructure was formed with crystal size increased up to 2-3μm for IPS e.max CAD while 1-2μm for the Rosetta SM. Also, Porto et al (2019) (32) , recorded rough surface of IPS e.max CAD with peaks and valleys, with cracks and hackles in small areas. They also found that CAD/CAM ceramics were not affected by aging and performed better after hydration.…”

“…Heat treatment, base glass composition, and nucleating agents greatly affects crystals' size among different factors (44) . Also, some researchers concluded that thermal stressing may cause tensions within the material which consequently slows down crack growth (32,45) .…”

Evaluation of mechanical properties of CAD/CAM ceramic systems: literature review

“…the failure of a material subjected to stresses or deformations over a period of time [15]. The composition and the conformation of each ceramic confers to its mechanical properties, which can favor or hinder the development of factures by fatigue [18] (chart 5).…”

“…Some examples of ceramics in this condition are: lithium disilicate glass-ceramic (IPS e.max Press or CAD by Ivoclar-Vivadent), fine-grained zirconia (e.g. Lava Plus from 3M ESPE, Bruxzir from Glidewell, Allzir from New Image) and surface-infiltrated glass (chart 6) [15,18,19].…”

Effect of Nanoparticles Modified Glass Ionomer Cement on the Colour and Shear Bond Strength of Lithium Disilicate Ceramic

“…(2) This ceramic material meets the esthetic requirements and represents an economic alternative to ZrO 2 -supported single tooth restorations. (3) According to the manufacturer, it can be cemented by use of the adhesive, self-adhesive or conventional techniques. This later technique can be used with glass ionomer cement.…”