Failure behavior of zirconia crowns subjected to air abrasion with different particle sizes

Abstract

This study aimed to investigate the failure behavior of 3 mol.% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP) prosthetic crowns air-abraded with aluminum oxide (AO) particles of different sizes. Ninety ceramic premolar crowns were produced with 3Y-TZP frameworks veneered with porcelain. Crowns were randomly divided into three groups, according to the size of the air abrasion AO particles (n = 30): (GC) untreated (control); (G53) 53 µm; (G125) 125 µm. Air abrasion was performed with 0.25 mpa pressure, 10-mm distance, for 10 s. Crowns were adhesively cemented to dentin analog abutments. Specimens were loaded in compression to failure, in 37oC distilled water, using a universal testing machine (n = 30). Fractographic analysis was performed using a stereomicroscope and SEM. The roughness of the crown’s inner surface was evaluated using an optical profilometer (n = 10). Fracture load data were statistically analyzed with Weibull analysis and roughness data with Kruskal-Wallis (α = 0.05). GC had the lowest characteristic fracture load (L0), while G53 and G125 had higher and statistically similar L0 values. The Weibull modulus (m) was similar among groups. The failure modes observed were catastrophic failure and porcelain chipping. There were no differences between the roughness parameters for the experimental groups (p > 0.05). The size of the AO particles did not affect the fracture load and failure mode of 3Y-TZP crowns. Air abrasion with 53 µm and 125 µm particles resulted in a higher fracture load of ceramic crowns than the untreated group while maintaining their reliability and surface characteristics.

A Comparison of Failure Loads for Polycrystalline Zirconia Ceramics with Varying Amounts of Yttria, Glass-Ceramics and Polymers in Two Different Test Conditions

“…Surprisingly, the results were the opposite for the crown specimens, where the 4Y-PSZ and 5Y-PSZ specimens revealed much higher failure loads than 3Y-PSZ. Possible reasons for this discrepancy include the role of crown thickness [15,16], surface treatment [16][17][18], and cement type [38]. There are no ISO and ASTM standards for crown testing, in terms of cement type/thickness, crown thickness, or internal surface treatment.…”

“…With the development of newer engineering materials, part of the tetragonal phase has been replaced with the cubic phase to yield yttria-partially stabilized zirconia (Y-PSZ) with a cubic phase that improves optical properties to be comparable with glass ceramic restorations [8]. The mechanical properties of zirconia restorations can be attributed to the type, and amount of stabilizing oxide [9][10][11][12][13][14][15], surface treatment [16][17][18], sintering conditions [19], ceramic thickness [15,16], zirconia phase [20,21], and translucency [22]. It has been shown that decreasing the amount of yttria strengthens zirconia [15], while increasing the yttria concentration increases its translucency [9], thus creating a trade-off between these desirable properties.…”

Effect of the CAD/CAM Milling Protocol on the Fracture Behavior of Zirconia Monolithic Crowns

“…Before cementation, crowns and abutments were sonically cleaned with isopropyl alcohol for 5 min. The dentin analog abutments were etched using 10% hydrofluoric acid (HF) for 60 s (Condac Porcelana, FGM, Joinville, SC, Brazil) in order to produce micro-retention for adhesive bonding, washed for 30 s, air-dried, and a silane bonding agent (Prosil, FGM, Joinville, SC, Brazil) was applied and allowed to evaporate for 60 s [ 7 , 16 , 29 ]. An adhesive system (ED Primer A + B, Kuraray, Tokyo, Japan) was applied to the dentin analog surface prior to cementation.…”

“…Resin-based cement pastes (Panavia F, Kuraray, Tokyo, Japan) were mixed and applied to the internal surface of the crown. The crown was placed over the abutment with finger pressure and assembled to a cementation device, in which a static load of 750 g was applied to the occlusal surface for 5 min (aiming to standardize the cement thickness) [ 7 , 29 ]. The excess cement was removed from the margins and light cured (1200 mW/cm 2 ) for 20 s at each surface, including the occlusal surface (Radii-cal, SDI Brasil Ind.…”

“…Cyclic loading of ceramic materials in a humid environment can lead to slow crack growth and affect the toughening mechanisms of materials, resulting in fatigue failure or degradation of their properties [ 19 , 27 , 28 ]. Moreover, the structural reliability of ceramics is associated with the size, density, and distribution of the flaws, which can be indirectly assessed using a Weibull analysis [ 29 , 30 ].…”