Effect of water storage on the shear bond strength of a cyanoacrylate adhesive: clinical implications.

Aim: To compare the effects of water storage on the shear bond strength of a cyanoacrylate adhesive system at three time intervals: (1) within 30 minutes after bonding the bracket to the tooth; (2) 24 hours from the time of bonding; and (3) after 30 days of storage in water at 37 degrees C.

Methods: Sixty freshly extracted human molars were collected and stored in a solution of 0.1% (weight/volume) thymol. The teeth were cleansed and polished, then randomly separated into three groups: group 1, cyanoacrylate adhesive debonded within 30 minutes from initial bonding; group 2, cyanoacrylate adhesive debonded after 24 hours immersion in deionized water at 37 degrees C; group 3, cyanoacrylate adhesive debonded after 30 days immersion in deionized water at 37 degrees C.

Results: Analysis of variance (F = 11.94) comparing the experimental groups indicated the presence of significant differences between the three groups (P = .0001). The shear bond strengths were significantly greater in the two groups debonded after 30 minutes (mean = 5.8+/-2.4 MPa) and 24 hours (mean = 7.1+/-3.3 MPa) than the group debonded after 30 days of water storage (mean = 2.7+/-2.0 MPa).

Conclusion: The present findings indicate that the cyanoacrylate adhesive has clinically adequate shear bond strengths at 30 minutes and 24 hours after initial bonding, but that the bond strength decreases by 50% within 30 days. The clinician needs to carefully take the overall properties of the adhesive into consideration.