IADR Abstract Archives
Comparison of Fatigue Strength Between Universal and Two-step Self-etch Adhesives
Objectives: The purpose of this study was to examine the shear fatigue strength (SFS) of resin composite bonded to enamel and dentin using universal adhesives and two-step self-etch adhesives.
Methods: Five universal adhesives (Adhese Universal; All-Bond Universal; Clearfil Universal Bond Quick; G-Premio Bond and Scotchbond Universal) and three two-step self-etch adhesives (Clearfil SE Bond; Clearfil SE Bond 2 and OptiBond XTR) were used to determine the SFS of a resin composite (Z100 Restorative) bonded to enamel (with and without phosphoric acid pre-etching) and dentin:). The SFS tests were conducted using a sine wave at a frequency of 20 Hz for 50,000 cycles or until failure occurred using 20 specimens per group. Statistical comparisons were made using a modified t-test with a Bonferroni correction.
Results: Phosphoric acid pre-etching of enamel significantly increased (p<0.05) the SFS of universal adhesives (with pre-etching: 17.8-22.0 MPa; and without pre-etching: 13.2-13.9 MPa), but its effect on two-step self-etch adhesives was material-dependent. Universal adhesives in self-etch mode showed a lower SFS to enamel (13.2-13.9 MPa) than the two-step self-etch adhesives (15.9-20.2 MPa), although enamel pre-etching for G-Premio Bond and Scotchbond Universal (21.0-22.0 MPa) resulted in similar SFS durability when compared to the two-step self-etch adhesives (22.1-22.4 MPa). The universal adhesives (11.1-15.6 MPa), apart from Scotchbond Universal (20.4 MPa), exhibited significantly lower SFSs to dentin than the two-step self-etch adhesives (22.9-23.5 MPa). The SFSs to dentin of the universal adhesives (11.1-20.4 MPa) also showed significant differences among the adhesives, unlike those of the two-step self-etch adhesives (22.9-23.5MPa).
Conclusions: These results appear to encourage the continued use of two-step self-etch adhesive when compared to universal adhesives. The results of this laboratory study are also consistent with reported clinical investigations on the durability of these types of adhesive systems, suggesting that SFS measurements may be helpful in predicting clinical performance.
Methods: Five universal adhesives (Adhese Universal; All-Bond Universal; Clearfil Universal Bond Quick; G-Premio Bond and Scotchbond Universal) and three two-step self-etch adhesives (Clearfil SE Bond; Clearfil SE Bond 2 and OptiBond XTR) were used to determine the SFS of a resin composite (Z100 Restorative) bonded to enamel (with and without phosphoric acid pre-etching) and dentin:). The SFS tests were conducted using a sine wave at a frequency of 20 Hz for 50,000 cycles or until failure occurred using 20 specimens per group. Statistical comparisons were made using a modified t-test with a Bonferroni correction.
Results: Phosphoric acid pre-etching of enamel significantly increased (p<0.05) the SFS of universal adhesives (with pre-etching: 17.8-22.0 MPa; and without pre-etching: 13.2-13.9 MPa), but its effect on two-step self-etch adhesives was material-dependent. Universal adhesives in self-etch mode showed a lower SFS to enamel (13.2-13.9 MPa) than the two-step self-etch adhesives (15.9-20.2 MPa), although enamel pre-etching for G-Premio Bond and Scotchbond Universal (21.0-22.0 MPa) resulted in similar SFS durability when compared to the two-step self-etch adhesives (22.1-22.4 MPa). The universal adhesives (11.1-15.6 MPa), apart from Scotchbond Universal (20.4 MPa), exhibited significantly lower SFSs to dentin than the two-step self-etch adhesives (22.9-23.5 MPa). The SFSs to dentin of the universal adhesives (11.1-20.4 MPa) also showed significant differences among the adhesives, unlike those of the two-step self-etch adhesives (22.9-23.5MPa).
Conclusions: These results appear to encourage the continued use of two-step self-etch adhesive when compared to universal adhesives. The results of this laboratory study are also consistent with reported clinical investigations on the durability of these types of adhesive systems, suggesting that SFS measurements may be helpful in predicting clinical performance.