Effect of different surface treatments on surface roughness, phase transformation, and biaxial flexural strength of dental zirconia

Abstract

Background. Interfacial failures at the cement‒restoration interface highlights the importance of effective surface treatment with no adverse effect on the zirconia’s mechanical properties. This study aimed to determine the effect of different surface treatments on dental graded zirconia’s surface roughness and certain mechanical properties. Methods. Forty sintered zirconia specimens were randomly divided into four groups (n=10): control (no surface treatment), sandblasting (SA), grinding with diamond bur (GB), and Er,Cr:YSGG laser (LS). Following surface treatment, the surface roughness and surface topography of the specimens were examined. X-ray diffraction (XRD) was conducted. In addition, the biaxial flexural strengths of specimens were evaluated. The data were analyzed using one-way analysis of variance (ANOVA) and post hoc Tukey tests; the Pearson correlation coefficient was calculated between either volumetric percentage of monoclinic phase or roughness and flexural strength of specimens (α=0.05). Results. The GB group exhibited significantly greater surface roughness compared to the other groups (P<0.005). The LS and control groups exhibited a significantly lower volumetric percentage of the monoclinic phase (P<0.001) than the GB and SA treatments. The SA group exhibited significantly higher flexural strength than the control (P=0.02) and GB groups (P<0.01). Furthermore, the Weibull analysis for the LS showed higher reliability for the flexural strength than other treatments. Conclusion. Er,Cr:YSGG laser treatment, with the lowest extent of phase transformation and reliable flexural strength, can be a promising choice for surface treatment of zirconia.

Adhesive Cementation of Zirconia Based Ceramics-Surface Modification Methods Literature Review

“…Additionally, a lower percentage of monoclinic phase was observed in the samples subjected to laser ablation compared to sandblasted samples, with comparable flexural strength. Moreover, it was found that the distribution of defects in the material created during laser processing is controlled and homogeneous [21]. Furthermore, in-vitro results confirm that both the femtosecond laser (FEMTO) surface treatment of high translucency zirconia and sandblasting with alumina of different grain sizes (50 and 90 µm) gives similar bond strengths with resin cements.…”

“…In order to obtain a high bond strength between zirconium ceramics and resin cement, it is necessary to obtain a micromechanical and chemical bond. Numerous studies confirm that the zirconium surface should be prepared before the resin cement application, as all conditioning methods improve the quality of the zirconium-resin bond strength [2,4,10,[19][20][21][22]. Various surface treatment methods are recommended for micromechanical and chemical combination, including mechanical treatment, laser irradiation, chemical treatment, coupling agents and ceramic coatings [15,20,[23][24][25].…”

“…After laser application, as after sandblasting, a rough material surface with increased wettability is obtained, which is micromechanically bonded with the resin cement [37]. The literature describes the modification of the zirconium oxide surface with lasers such as: Er: YAG, Nd: YAG, Yb: YAG, Er, Cr: YSGG, Yb: KGW, CO 2 with different power, energy consumption, distance and time parameters duration [20,21,36,38,39]. However, the use of lasers to treat zirconium oxide is debatable.…”

Effect of nonthermal argon plasma treatment on the surface properties and phase transformation of zirconia

“…Surface treatment on zirconia can cause localized stress and induce its transformation from a tetragonal to a monoclinic phase, which adversely affects the mechanical properties of the material, such as its hardness, flexural strength, and modulus of elasticity. Therefore, developing a surface treatment modality that can roughen the surface with minimal phase transformation is very much desired [19,20].…”

Comparison of Polishing Effects of Different Polishing Systems on Highly-Translucent Monolithic Y-TZP Ceramics

“…Some research results have shown that the phase transformation of zirconia surface is directly related to the damage caused by surface treatment, and many stimulus factors can lead to the formation of small cracks, such as thermal change, humidity, particle wear and grinding in the air, etc., while the area with surface defects and defects is a potential place for crack initiation and expansion to the stress concentration area [14].Under different ambient temperature conditions, there are three crystal phases of zirconia. It has been reported that clinical grinding of the contour and bite of zirconia restorations provides external energy through local heat and friction generation in zirconia, resulting in local M-phase transformation [15,16].…”