Bonding Performance of Recent Self-etch Adhesive Systems under Combination Stress

Objective: The purpose of this study was to examine the bonding performance of four recent self-etch adhesive systems, i.e., three one-bottle all-in-one systems; Tokuyama Bond Force (BF, TOKUYAMA), Adper Easy Bond (EB, 3M ESPE), and Clearfil Tri-S Bond (TS, KURARAY), and a two-bottle self-etching primer system; Adper Scotchbond SE (SS, 3M ESPE), as compared with that of a popular two-bottle self-etching primer system; Clearfil SE Bond (SE, control, KURARAY).

Methods: Standardized V-shaped cavity was prepared in the cervical region of 50 extracted human premolars. The cavities were pretreated with the five systems (n=10 each) and then restored clinically according to the manufacturer's instructions. The restored specimens were subjected to a combination stress load condition simulating oral environment; thermocycling(4°C/60°C×1,250sets) and simultaneous repeated-load(12kgf×10⁵times). Each specimen was longitudinally serially sectioned into two slabs of 1.0mm thickness. The slabs were trimmed into a standardized dumbbell-form specimen. The measurement of micro-tensile bond strength (µ-TBS, n=20 each) to the dentin wall of the specimens was attempted. The data of µ-TBS were examined using t-test and Weibull analysis.

Results: The mean µ-TBS(s.d.) in MPa / Weibull modulus were BF;11.4(4.2)/2.83, EB;26.7(10.9)/2.37, TS;13.7(3.1)/4.51, SS;14.5(5.2)/uncalculatable, SE;15.4(7.4)/2.47. The µ-TBS of SS was based on 4 slabs, because 16 slabs were debonded during trimming procedures. The µ-TBS of EB was significantly greater than those of the other systems and the value of BF was statistically smaller than that of SE. Weibull modulus of TS was greater than those of BF, SE and EB at p<0.01, and no difference in the modulus was recognized among SE, BF and EB.

Conclusion: The bonding durability of EB was superior to SE, and that of TS was similar to SE. TS had better bonding reliability than SE, and the reliability of EB and BF was similar to SE.