Bond Strengths of Self-Etch Adhesives to Enamel Measured Immediately and 24 Hours after Placement
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Date
2010-09-01
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Journal of the Dental Association of Thailand
Abstract
In clinical situations, the bonded interface between tooth substrate and resin-based composite is inevitably subjected to stresses immediately after its placement. The present study aims to evaluate and compare the bond strengths of two self-etch adhesives to enamel measured immediately and 24 hours after placement. Intact, non-carious, non-restored human permanent molars were mesio-distally sectioned into halves. Each half was mounted into stone plaster with middle enamel surface exposed to the environment. The enamel surfaces were ground flat with abrasive paper and restored with resin-based composite using either Clearfil Tri-S Bond or Clearfil SE Bond. Microshear bond strengths were assessed immediately or 24 hours later. Bond strength data were analyzed with two-way ANOVA. The fractured surfaces were observed under stereomicroscope and failure mode frequencies were compared using the Chi-square test. Representative enamel surfaces after each adhesive treatment were examined under scanning electron microscope (SEM). No statistically significant difference in shear bond strengths was detected between the two adhesives (p = .224);however, significantly lower values were revealed at the time immediately after resin-based composite placement (p \< .001) as compared to 24 hours later. Immediately after placement, Clearfil Tri-S Bond specimens were more likely to have failure pathway in adhesive layer than Clearfil SE Bond specimens (p = .001). Under SEM observations, both adhesives created rough enamel surfaces after treatments with acidic monomers.From the results of this study, it can be concluded that enamel bonding effectiveness of both self-etch adhesives was not different; however from each other, shear bond strengths measured immediately were shown to be lower than those measured 24 hours afterward.
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Journal of the Dental Association of Thailand; Vol. 59 No.4 October-December 2009; 245-255