TY - JOUR
T1 - Single-step, self-etch adhesives behave as permeable membranes after polymerization. Part I. Bond strength and morphologic evidence
AU - Tay, Franklin R.
AU - Pashley, David H.
AU - Suh, Byong
AU - Carvalho, Ricardo
AU - Miller, Michael
PY - 2004/8
Y1 - 2004/8
N2 - Purpose: To test the hypotheses that microtensile bond strengths of single-step, self-etch adhesives to hydrated dentin are adversely affected by delayed-activation of a light-cured composite, as well as the use of a chemical-cured composite. Methods: Seven commercially available and one experimental single-step, self-etch adhesives were bonded to hydrated human dentin. A dual-cured composite was used and activated using: [1] the light-cured mode (base paste only - control), [2] the chemical-cured mode (base and catalyst pastes, in the dark); and [3] delayed light-activation (base syringe only, left on top of cured adhesives in the dark for 20 minutes before activation). After micro-tensile bond strength evaluation, fractured samples were examined using SEM. Intact, unstressed interfaces of [1] and [3] were examined with TEM. Microtensile bond strengths were also evaluated for selected adhesives bonded to dehydrated dentin and coupled with the composite activated by [2] or [3]. Results: For all adhesives, bond strengths decreased significantly to bonded hydrated dentin when the composites were activated with [2] or [3] (P< 0.001). Whereas the hybrid layer-adhesive interface was intact, water-blisters that developed along the adhesive-composite interface in these two modes were responsible for the decline in bond strength. When bonded to dehydrated dentin, delayed light-activation of the light-cured composite did not result in compromised bond strength. The results of chemical-cured composites improved but were more variable and system-dependent.
AB - Purpose: To test the hypotheses that microtensile bond strengths of single-step, self-etch adhesives to hydrated dentin are adversely affected by delayed-activation of a light-cured composite, as well as the use of a chemical-cured composite. Methods: Seven commercially available and one experimental single-step, self-etch adhesives were bonded to hydrated human dentin. A dual-cured composite was used and activated using: [1] the light-cured mode (base paste only - control), [2] the chemical-cured mode (base and catalyst pastes, in the dark); and [3] delayed light-activation (base syringe only, left on top of cured adhesives in the dark for 20 minutes before activation). After micro-tensile bond strength evaluation, fractured samples were examined using SEM. Intact, unstressed interfaces of [1] and [3] were examined with TEM. Microtensile bond strengths were also evaluated for selected adhesives bonded to dehydrated dentin and coupled with the composite activated by [2] or [3]. Results: For all adhesives, bond strengths decreased significantly to bonded hydrated dentin when the composites were activated with [2] or [3] (P< 0.001). Whereas the hybrid layer-adhesive interface was intact, water-blisters that developed along the adhesive-composite interface in these two modes were responsible for the decline in bond strength. When bonded to dehydrated dentin, delayed light-activation of the light-cured composite did not result in compromised bond strength. The results of chemical-cured composites improved but were more variable and system-dependent.
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M3 - Article
C2 - 15478490
AN - SCOPUS:1942473521
SN - 0894-8275
VL - 17
SP - 271
EP - 278
JO - American journal of dentistry
JF - American journal of dentistry
IS - 4
ER -