Bonding Durability of Recent All-in-one Adhesive Systems under Thermocycled Repeated-load

Objective: The purpose of this study was to examine the bonding durability of three recent all-in-one adhesive systems, two latest experimental one-bottle one-step system; EXL759 (EXL, 3M ESPE) and MTB200 (MTB, KURARAY), and a popular systems on the market; Adper Easy Bond (EB, 3M ESPE), as compared with that of a two-bottle two-step self-etching primer system; Clearfil SE Bond (SE, control, KURARAY).

Method: Standardized V-shaped cavity was prepared in the cervical region of 80 extracted human premolars. The cavities were pretreated with the four systems (20 each) and then restored clinically according to the manufacturer’s instructions. A half of the restored specimens (10 each system) were subjected to thermo-mechanical repeated stress condition simulating intra-oral environment; thermocycling (5ºC/55ºC×2,000 sets) and simultaneous repeated-load (12kgf×10⁵ times). Another half of specimens were supplied as non-stress control group. Micro-tensile bond strengths (µ-TBS) to the gingival dentin wall of the specimens with and without the stress load were measured. The data of µ-TBS were examined using ANOVA, Tukey’s q-test and Student’s t-test.

Result: The mean µ-TBS(s.d.) in MPa of the specimens with/without the stress load were EXL;21.7(3.7)/23.3(3.9), MTB;21.1(3.2)/22.2(5.0), EB;26.9(8.4)/27.8(5.0), SE;14.8(5.5)/22.0(5.7). The µ-TBS of three recent all-in-one adhesive systems with the stress were significantly greater than that of SE at p<0.01, the values without stress were similar to or greater than the value of SE. The mode of the stress did not influence the µ-TBS of recent all-in-one systems, but had effect upon the µ-TBS of SE.

Conclusion: The bonding durability, based on the µ-TBS with and without a stress simulating intra-oral environment, of the three recent all-in-one adhesive systems was superior to that of SE. Two latest experimental all-in-one systems; EXL and MTB, demonstrated excellent bonding durability that could maintain the µ-TBS even under the stress condition.