Surface treatment with a fractional CO2 laser enhances shear bond strength of resin cement to zirconia

Abstract

Aims:The present study investigated the effect of different surface treatments on shear bond strength (SBS) of resin cement to zirconia. Materials and methods: Ninety zirconia blocks were prepared and divided into 6 groups of 15 by treatment. Group 1 served as the control group, whereas groups 2 and 3 were treated with air abrasion and a universal primer (Monobond plus), respectively. The remaining zirconia copings were treated with a fractional CO2 laser for 10 seconds using 10 W/10 mJ (group 4), 10 w/14 mJ (group 5) or 20 W/10 mJ (group 6). A luting cement (Clearfil SA) was bonded to the treated zirconia surfaces and cured for 40 seconds. SBS was measured with a universal testing machine and the type of bond failure was determined. Results: There was a statistically significant difference in SBS among the study groups (p<0.001). The highest SBS values were observed in the groups treated with the fractional CO2 laser at settings of 20 W/10 mJ (28.1 MPa) or 10 W/14 mJ (27.4 MPa), followed by the specimens treated with the universal primer (22.8 MPa). The control specimens exhibited the lowest SBS (9.4 MPa) among the study groups (p<0.05). There was no significant difference in the distribution of failure modes among the groups (p=0.871). Conclusions:The application of fractional CO2 laser can improve bond strength of resin cement to zirconia ceramic, and thus it could be considered as an appropriate alternative to conventional methods of zirconia surface treatment.

Effect of airborne particle abrasion and sintering order on the surface roughness and shear bond strength between Y-TZP ceramic and resin cement

“…It also increases the surface area and surface energy for the adhesion of resin cements and promotes micromechanical retention 44) . However, bonding to Y-TZP has always been a challenging issue, as the material is acid-resistant due to its polycrystalline structure 29,35,45) . To achieve adequate bond strength between Y-TZP and resin cement, airborne particle abrasion is recommended 36,46) .…”

CO₂ laser dentin surface treatment most effectively increased ceramic shear bond strength

“…This result can be attributed to the performance of CO2 laser irradiation in roughening ceramic surface through thermo-mechanical ablation, which increases micro-mechanical retention. This enhances the bond strength at the zirconia/cement interface 26,39) .…”

The Effect of Fractional CO2 Laser Irradiation on Shear Bond Strength of Resin Cement to Feldspathic Porcelain

“…They concluded that CO2 laser could provide the highest bond strength in In-Ceram Spinel group while in In-Ceram Alumina no significant difference was found among various surface treatments. The laser settings applied in this study were selected according to the results of previous studies 12,25 and the results of our pilot study to find the minimum laser parameters that can etch the porcelain surface. Some studies reported increased surface roughness after the use of different lasers for surface conditioning of ceramics.…”

“…The choice of power and energy were 20 W/10 mJ and 15 W/ 20 mJ in groups 3 and 4, respectively. These parameters were taken from previous studies, 12,25 and the results of our pilot study (data have not been presented) to find the parameters that etch the feldspathic porcelain without creating visible thermal damage. The surfaces of the specimens in group 5 were first irradiated with the fractional CO2 laser under the same conditions as described in group 4 (15 W/20 mJ) and then treated with 9.6% HF acid for 2 minutes, similar to the control group.…”