Effects of Different Storage Conditions on Mechanical Properties of CAD/CAM Restorative Materials

Abstract

The aim of this study was to evaluate mechanical properties of six new-generation all-ceramic materials for CAD/CAM (Lava Ultimate [LU], VITA Mark II [VM], InCoris TZI [IC], IPS e.max CAD [EM], VITA Suprinity [VS], IPS Empress CAD [EC]) and two different provisional restoration CAD/CAM materials (Telio CAD [TC], Vita CAD-Temp [VC]) after different storage conditions. 36 bar-shaped samples of 4 mm in width and 14 mm in length with 1.2 mm thicknesses were prepared from each material group (N=288). The specimens from each material were kept under three different storage conditions (n=12): under dry conditions at room temperature; 37°C distilled water for 7 days; and 37°C distilled water for 7 days followed by 10,000 thermal cycles. All specimens were subjected to a 3-point flexural test with a crosshead speed of 1.0 mm/min. The specimens were loaded until failure. Twelve fractured specimens after the flexural test from each group were used for the Vickers hardness test (under 300 gf of loading in 15 seconds). The flexural modulus, flexural strength and Vickers hardness values were separately analyzed with two-way analysis of variance, Tukey’s multiple comparison tests at a significance level of p<0.05. There were statistically significant differences between materials and storage conditions according to flexural modulus, flexural strength and Vickers hardness values (p<0.05). The flexural strength, flexural modulus and Vickers hardness values of LU, VC, TC, VS and IC decreased after water storage followed by thermal cycling (p<0.05). The mechanical properties of provisional restoration CAD/CAM materials had showed a significantly decrease after water storage followed by thermal cycles but their mechanical properties were acceptable for fabrication of provisional restorations. The mechanical properties of VM, EC and EM were not affected by different storage conditions whereas IC and VS were affected.

Fracture resistance and fracture modes in endodontically treated maxillary premolars restored using different CAD-CAM onlays

“…These inconsistent results might be due to different aging protocols, such as the number of thermal cycles and fatigue loading. For the IPS e.max CAD, the current data show that water storage and thermocycling do not significantly decrease the mechanical properties of the materials in terms of fracture toughness, flexural strength, and hardness [26,56,58,59]. By contrast, thermocycling and cyclic loading induce low-temperature degradation (LTD) and degrade the mechanical properties of zirconia [60,61].…”

Fracture resistance of bi-layered and translucent zirconia after thermo-mechanical fatigue

“…Thermal-fatigue process affects physical, chemical and mechanical properties of restorative FRACTURE RESISTANCE OF BI-LAYERED AND TRANSLUCENT ZIRCONIA AFTER THERMO-MECHANICAL (1807) materials such as water sorption leading to component hydrolysis, in addition, hot-cold passages lead to expansion-shrinkage. Zirconia is more susceptible to low temperature degradation in presence of water (46) .…”

The Biaxial Flexural Strength and Weibull Analysis of Polished and Glazed CAD/CAM Polymethylmethacrylate Provisional Material..

“…Long-term provisional restorations play a crucial role in certain clinical circumstances, such as oral implantation treatment or comprehensive occlusal therapy, that are exposed to significant functional stresses. (7), (8) Therefore, it is essential for the long-term provisional restorative material to possess favorable flexural strength, enhanced wear resistance, dimensional stability, low creation of marginal gaps, as well as higher resistance to staining and discoloration. (9) Commonly used conventional provisional resin materials have varying chemical and polymerization characteristics, as well as physical and mechanical properties.…”