Bond efficacy and interface morphology of self-etching adhesives to ground enamel.
OBJECTIVE
This study compared the microshear bond strengths to ground enamel of three one-step self-etching adhesive systems, a self-etching primer system and an etch-and-rinse adhesive system.


METHODS
Three self-etching adhesives, Futurabond DC (Voco), Clearfil S Tri Bond (Kuraray) and Hybrid bond (Sun-Medical), a self-etching primer, Clearfil SE Bond (Kuraray), and an etch-and-rinse system, Admira Bond (Voco), were selected. Thirty human molars were used. The root of each tooth was removed and the crown was sectioned into halves. The convex enamel surfaces were reduced by polishing on silicone paper to prepare a flat surface. The bonding systems were applied on this surface. Prior to adhesive curing, a hollow cylinder (2.0 mm height/0.75 mm internal diameter) was placed on the treated surfaces. A resin composite was then inserted into the tube and cured. After water storage for 24 h, the tube was removed and shear bond strength was determined in a universal testing machine at a crosshead speed of 0.5 mm/min. The results were analyzed with ANOVA and the Tukey.-Kramer test at a 59 degrees confidence level. The enamel of five additional teeth was ground, and the etching component of each adhesive was applied and removed with absolute ethanol instead of being light cured. These teeth and selected fractured surfaces were examined by SEM.


RESULTS
Adhesion to ground enamel of the Futurabond DC (25 +/- 3.5 MPa) and Clearfil SE Bond (23 +/- 2.9 MPa) self-etching systems was not significantly different from the etch-and-rinse system Admira Bond (27 +/- 2.3 MPa). The two self-etching adhesives Clearfil S Tri bond and Hybrid Bond demonstrated significantly lower bond strengths (14 +/- 1.4 MPa; 11 +/- 1.9 MPa) with no significant differences between them (p < 0.05).


CONCLUSIONS
Bond strengths to ground enamel of self-etching adhesive systems are dependent on the type of adhesive system. Some of the new adhesive systems showed bond strength values comparable to that of etch-and-rinse systems. There was no correlation between bond strength and morphological changes in enamel.
Abdalla
Ali I
AI
Department of Restorative Dentistry, Faculty of Dentistry, University of Tanta, Tanta, Egypt. ali_abdalla79@yahoo.com
El Zohairy
Ahmed A
AA
Abdel Mohsen
Mohamed M
MM
Feilzer
Albert J
AJ
D000134:Acid Etching, Dental / Q000379:methods*; D000269:Adhesives / Q000737:chemistry*; D000704:Analysis of Variance; D001840:Dental Bonding; D003743:Dental Enamel; D003799:Dental Stress Analysis; D006801:Humans; D008422:Materials Testing; D019279:Resin Cements; D033081:Shear Strength; D018709:Statistics, Nonparametric; D013499:Surface Properties
D000269:Adhesives; D019279:Resin Cements