Effect of laser and surface treatments on bond strength of luting agents to colored and non-colored zirconia

The purpose of this study was to evaluate the effects of different surface treatments and zirconia type (white or colored) on shear bond strength (SBS) between zirconia and resin cements. Two main groups were created according to zirconia color. After coloring, white and colored sintered zirconia was divided into four surface treatment groups: control, air abrasion, silica coating, and air abrasion + erbium-doped yttrium-aluminum-garnet (Er:YAG) laser (n=20). After surface treatment, surface roughness and scanning electron microscopic analyses were conducted. Then, Panavia F 2.0 and RelyX Ultimate Clicker cements were each applied to 10 specimens from each subgroup. The specimens were stored in distilled water at 37°C for 24 h, and then subjected to 5,000 thermal cycles between 5°C and 55°C. SBS was measured using a universal testing machine at a crosshead speed of 0.5 mm/min. SBS values were compared using analysis of variance and Turkey’s honestly significant difference test (p < 0.05). Roughness values were analyzed using ordinary linear regression. SBS was significantly greater in the air abrasion + Er:YAG laser group (14,055 MPa), and the control group (5,678 MPa) had the lowest value; it did not differ between the air abrasion and silica coating groups. SBS of colored specimens (9, 33 MPa) was significantly lower than that of white specimens (10,45 MPa). Roughness was related significantly to bond strength. These results show that all tested surface treatments were suitable, but that air abrasion + Er:YAG laser treatment was most effective.