To evaluate the influence of air-particle abrasion and treatments on in vitro tensile bond strength of resin composite bonded to human enamel was evaluated using a single-bottle adhesive.
Human teeth were divided into 12 groups of three treatments (none, 27-microm Al2O3 air-particle abrasion, 50-microm Al2O3 air-particle abrasion) and four conditioners [none, phosphoric acid (PA), NRC (no-rinse conditioner), and PA/NRC]. Bonding agent (Prime & Bond NT) and a resin composite (TPH Spectrum) were applied as inverted cones. Specimens were stored for 24 hours at 37 degrees C and debonded in tension using a testing machine at 0.5 mm/minute.
Phosphoric acid treatment used with Prime & Bond NT produced the best bond strengths (24 MPa) to enamel for surfaces treated with 27-microm air-particle abrasion and for surfaces not treated with air-particle abrasion (control). With one exception, air-particle abraded surfaces resulted in bond strengths between 9 to 16 MPa. NRC with or without the use of phosphoric acid in general did not improve tensile bond strength to enamel when compared to surfaces not treated with NRC.