Effects of Irradiation with a CO2 Laser on Surface Structure and Bonding of a Zirconia Ceramic to Dental Resin Cement

Studies have suggested that irradiation with a CO 2 laser may improve the shear bond strength between resin cement and zirconia. One hundred and ten specimens of zirconia randomly divided into four groups, of which we respectively treated the first three with air abrasion, irradiation with a CO 2 laser, and irradiation with a CO 2 laser followed by air abrasion, with the fourth group serving as an untreated control. Resin cement create a column 2 mm thick and 3.6 mm in diameter on each ceramic specimen. The shear bond strength between the resin and ceramic was determined at a crosshead speed of 0.5 mm/min. The bond strength between the resin and laser-treated ceramic varied with the laser power setting at which the ceramic was treated. The strength was greatest at a power setting of 8W, with a value of 6.7 MPa. Combined treatment of the zirconia ceramic with CO 2 laser irradiation and air abrasion produced a threefold greater strength of the resin-to-ceramic bond over that with the zirconia control and a 20% greater strength between the resin and the ceramic treated with air abrasion. The CO 2 laser irradiation of zirconia ceramic can significantly increase the adhesive strength of its bonding to a dental resin cement.