Shear bond strength of Nd:YAG laser-irradiated versus acid-etched human enamel

Abstract This study was undertaken to evaluate the effect of short-time acid etching after laser irradiation on the shear bond strength. Seventy-five freshly extracted human premolars were used. Laser irradiation was performed with pulsed wave, 200 mJ/pulse and 10 or 15 pps. Group 1: conventional acid etching for 30 s (35% phosphoric acid), Group 2: lased (10 pps) to coated with India ink+acid etching for 10 s, Group 3: lased (15 pps) to coated with India ink+acid etching for 10 s, Group 4: lased (10 pps) to coated with tannin fluoride (Hyc)+acid etching for 10 s, Group 5: lased (15 pps) to coated with Hyc+acid etching for 10 s. After application of bonding agents, the orthodontic brackets were placed on the buccal surface with orthodontic resin. Shear bond tests at a cross-head speed of 1.0 mm/min were performed. Shear bond strength results were as follows: Group 1=6.11±3.54 MPa, Group 2=22.05±6.01 MPa, Group 3=14.79±6.52 MPa, Group 4=17.62±6.53 MPa, Group 5=16.75±5.33 MPa. The short-time etching after laser irradiation had significantly higher bond strength than conventional acid etching ( p p