Fatigue of enamel bonds with self-etch adhesives.
OBJECTIVE
Fatigue testing of adhesive bonds to tooth structures in conjunction with bond strength testing can provide more useful information for examining the effectiveness of dental adhesives. The purpose of this study was to determine the shear bond strength (SBS) and shear fatigue limit (SFL) of composite to enamel bonds using modern adhesive systems.


METHODS
Twelve specimens each were used to determine 24-h resin composite (Z100-3M ESPE) to enamel shear bond strengths with an etch-and-rinse system (ERA), Adper Single Bond Plus (SB), and four self-etch adhesives (SEA)--Adper Prompt-L-Pop (PLP), Clearfil SE (CSE), Clearfil S(3) (CS3) and Xeno IV (X4). A staircase method of fatigue testing was used in a four-station fatigue cycler to determine the SFL of composite to enamel bonds with the adhesives (16-20 specimens for each adhesive) at 0.25 Hz for 40,000 cycles. ANOVA and Tukey's post hoc test were used for the SBS data and a modified t-test with Bonferroni correction was used for comparisons of the SFL.


RESULTS
The SBS and SFL of the etch-and-rinse system were significantly greater (p<0.05) than those of the four self-etch adhesives. The SBS and SFL of CSE were also significantly greater than for the other three self-etch systems. The ratio of SFL to SBS was highest with the etch-and-rinse system and the ratio became increasing smaller in the same order that the values for SBS decreased with the self-etch systems.


CONCLUSIONS
The lower fatigue limits for composite to enamel bonds obtained with the self-etch adhesive systems may indicate that greater enamel margin breakdown will occur with restorations where these systems are used for bonding.
Erickson
Robert L
RL
Department of General Dentistry, Creighton University School of Dentistry, 2500 California Plaza, Omaha, NE 68178, USA.
Barkmeier
Wayne W
WW
Kimmes
Nicole S
NS
D000134:Acid Etching, Dental / Q000379:methods*; D000268:Adhesiveness; D003188:Composite Resins; D001840:Dental Bonding; D003743:Dental Enamel; D003799:Dental Stress Analysis; D005899:Glass Ionomer Cements; D006801:Humans; D008422:Materials Testing; D019279:Resin Cements; D033081:Shear Strength
D003188:Composite Resins; D005899:Glass Ionomer Cements; D019279:Resin Cements