Influence of surface treatments and resin cement selection on bonding to zirconia

Abstract

This study aimed to evaluate the surface changes caused in zirconia by different surface treatments and the influence of the surface treatment and cement selection on bonding to zirconia under aging. Sintered zirconia specimens were divided into five groups (n = 31) based on the surface treatment, namely, control, air abrasion, silica coating, laser and air abrasion + laser. After surface treatment, surface roughness and microscope analyses were performed on one specimen of each group. Composite cylinders were then bonded to conditioned ceramics using RelyX U100 (RXU), Clearfil Esthetic Cement (CEC) and Panavia F (PF) (n = 10). After 24 h, the bonded specimens were subjected to thermal cycling (6,000 times), and then, a shear bond strength test was conducted. The roughness values were analysed using Kruskal-Wallis and Mann-Whitney U tests, and the bond strengths were analysed by two-way analysis of variance and Duncan's test. The relationship between the roughness and the bond strength was determined by Spearman's correlation analysis. Specimens subjected to surface treatments were rougher than the control specimen (p < 0.000). However, there were no significant differences between the air abrasion and air abrasion + laser groups and the silica coating and laser groups. Specimens treated with laser showed lower bond strengths irrespective of the resin cement used. CEC and/or PF showed higher bond strengths than RXU for each surface treatment group. No significant relationship was observed between the roughness and the bond strength. The results of this study showed that all the surface treatments, except for laser irradiation, were suitable for treating zirconia ceramics. Cement selection was found to be more important than surface treatment, and phosphate monomer-containing cements were suitable for cementing zirconia.

Effect of zirconia surface treatment using nitric acid-hydrofluoric acid on the shear bond strengths of resin cements

“…Time for etching zirconia surface was much longer than glass ceramics, and zirconia with 2-hour etching had the highest surface roughness value. According Subaşi and Inan13 average Ra scores were 0.22, 0.74, 0.35, and 0.34 in the control, air abrasion, silica-coating, and laser groups, respectively. The average Ra in the group that underwent air abrasion and laser together was 0.74.…”

“…Likewise, Subaşi and Inan13 have reported mixed type of failure modes in Panavia F2.0 and Rely X Unicem, suggesting these resin cements adequate for clinical usage and concluding that cement types were more important than surface conditioning methods.…”

Evaluation of roughness, wettability, and morphology of an yttria-stabilized tetragonal zirconia polycrystal ceramic after different airborne-particle abrasion protocols

“…15,16,19,22,27 Although the particles of Rocatec Soft (30 mm) were smaller than the others, SEM analysis found that they were able to roughen the zirconia surface more in comparison with the control group; the control group presented a surface that was less favorable to micromechanical retention and that abraded with Rocatec Soft was more favorable. This difference in morphology was also observed by Subaşı and _ Inan.…”

“…Although some alternative surface treatments provide mechanical bond, airborne-particle abrasion is one of the most used and studied methods for zirconia. 3,[9][10][11][12][13][14][15][16] Besides roughening the surface, this procedure cleans and increases the available surface area for bonding, favoring the mechanical interlocking between the luting cement and the airborne-particleabraded zirconia surface, 3,10,17 and also increases the surface free energy, which may enhance the wettability of the substrate. 18,19 For airborne-particle abrasion, a variety of particle sizes (25 mm to 250 mm) and compositions (conventional alumina or silica-coated particles) exist.…”

“…This difference in morphology was also observed by Subaşı and _ Inan. 15,16 The mean roughness value (Ra) found in the present study for the as-sintered group is consistent with the studies of Monaco et al 27 and Cavalcanti et al,11 and the roughness of the Rocatec Soft group is corroborated by the study of Cattani Lorente et al 22 The significantly higher roughness provided by 50-mm Al 2 O 3 particles in comparison with the control group and the group abraded with 30-mm silicacoated Al 2 O 3 particles was also found in the literature. 11,14,[27][28][29][30] Concerning the morphologic analysis, it was observed that, unlike in the control group (which exhibited a smooth surface), abrasion with Rocatec Soft and 50-mm The groups abraded with 120-mm Al 2 O 3 particles and 120-mm Al 2 O 3 particles þ Rocatec Plus provided the second highest roughness value.…”