Effect of Air-Abrasion Regimens and Fine Diamond Bur Grinding on Flexural Strength, Weibull Modulus and Phase Transformation of Zirconium Dioxide

Abstract

PURPOSE This study evaluated the effect of air abrasion and polishing regimens on the flexural strength of yttrium stabilized polycrystalline tetragonal zirconia (Y-TZP). METHODS From Y-TZP blocks (InCeram 2000 YZ Cubes; Vita Zahnfabrik, Bad Säckingen, Germany) 120 bars (25 mm × 4 mm × 1.2 mm) were obtained according to ISO 6872:2008 and randomly divided into 4 groups: Group C: (control) without surface treatment (n = 30); Group APA: Air abrasion with aluminum oxide (44 µm) (n = 30); Group SC: Silica-coating (CoJet, 30 µm) (n = 30); Group FD: Fine diamond bur (n = 30). Subsequently, all specimens were subjected to 4-point bending test (in distilled water at 37°C) in a universal testing machine (EMIC DL 1000; São José dos Pinhais, Paraná, Brazil); cross-head speed: 0.5 mm/min). The characteristic strength (0) of each specimen was obtained from the flexural strength test and evaluated using Weibull analysis. X-ray diffraction analysis was utilized to quantity the monoclinic phase. The surface topography of specimens was analyzed using 3D optical profilometer and scanning electron microscopy (SEM) after surface conditioning methods. The flexural strength data (4p) were statistically analyzed by 1-way ANOVA, Tukey test ( = 0.05) and Weibull (m = modulus, 0 = characteristic strength) were calculated. RESULTS The mean ± standard deviations (MPa) of the groups were as follows: C: 1196.2 ± 284.2a; APA: 1369.7 ± 272.3a; SC: 1207.1 ± 229.7a and FD: 874.4 ± 365.4b. The values (m) and (0) were as follows: C: 4.5 and 1308.12; APA: 5.9 and 1477.88; SC: 6.0 and 1300.28; and FD: 2.6 and 985.901, respectively. CONCLUSIONS Air particle abrasion with neither silica nor alumina showed significant difference compared to the control group but grinding with fine diamond bur impaired the flexural strength of the zirconia tested. The characteristic strength (σ 0 ) of each specimen was obtained from the flexural strength test and evaluated using Weibull analysis. X-ray diffraction analysis was utilized to quantity the monoclinic phase.The surface topography of specimens was analyzed using 3D optical profilometer and scanning electron microscopy after surface conditioning methods. were as follows: C: 4.5 and 1308.12; APA: 5.9 and 1477.88; SC: 6.0 and 1300.28; and FD: 2.6 and 985.901, respectively. Conclusions: Air particle abrasion with neither silica nor alumina showed significant difference compared to the control group but grinding with fine diamond bur impaired the flexural strength of the zirconia tested.

Effect of Grinding and Multi-Stimuli Aging on the Fatigue Strength of a Y-TZP Ceramic

“…defining the final outcome: if the balance tends to the introduction of defects it may be observed a negative impact (8,9,24), while if the balance favors phase transformation it could be observed the toughening mechanism (12,13,19). Our study corroborates that assumption, since we used the methodology preconized by this systematic review (14) to avoid defect introduction (handpieces coupled to slow speed motors and the use of plenty coolant) and we did not notice a deleterious effect, even using coarse diamond burs during grinding.…”

Comparison of Testing Designs for Flexural Strength of 3Y-TZP and 5Y-PSZ Considering Different Surface Treatment

“…An important parameter for the evaluation of dental zirconia is the flexural strength. Various methods have been established for analyzing flexural strength, for example, the three-point bending test and four-point bending test as uniaxial tests [ 8 , 9 , 10 ]. However, the piston-on-three-balls test is typically used to measure the biaxial flexural strength [ 5 , 11 , 12 , 13 ].…”

The effect of subpressure on the bond strength of resin to zirconia ceramic

“…Many surface treatments have been used to improve the bond strength of resin to zirconia ceramics over the past two decades, including air abrasion [ 11 ], diamond burs abrasion [ 12 ], silica (tribochemical) coating [ 13 ], silicoating [ 14 , 15 ],selective infiltration etching [ 16 ] and laser [ 17 , 18 ]. However, many studies have found microscopic cracks because these surface treatments can accelerate tetragonal-to-monoclinic (t→m) phase transformation [ 19 – 22 ], and other researchers found that airborne particle abrasion decreased micro tensile bond strength [ 23 ].…”