Single-step, self-etch adhesives behave as permeable membranes after polymerization. Part III. Evidence from fluid conductance and artificial caries inhibition.
OBJECTIVE
To test the hypothesis that formation of inhibition zones by bonded restorations in artificially-induced carious dentin lesions is related to the permeability of the self-etch adhesives.


METHODS
Fluid conductance of four single-step self-etch adhesives (Prompt L-Pop, Etch&Prime 3.0, One-Up Bond F and Reactmer Bond), and a control two-step self-etch adhesive (UniFil Bond) were measured after sound dentin surfaces were:(1) acid-etched; (2) polished to produce smear layers; (3) bonded with the adhesive; each at 20 cm hydrostatic pressure (hp). Osmotic fluid conductance was also determined for the bonded dentin after immersion in 4.8 M CaCl2 at 0 cm hp. For artificial caries inhibition, a non-fluoride releasing (NFR) two-step self-etch adhesive (UniFil Bond) and a fluoride-releasing (FR) single-step adhesive (Reactmer Bond) were used in combination with a NFR composite (Metafil CX) or a FR restorative material (Reactmer Paste). Artificial caries were induced in these restorations, from which 120 +/- 10 microm thick sections and the effect of caries inhibition were quantitatively assessed with polarizing light microscopy and image analysis.


RESULTS
Fluid conductance after bonding with the single-step adhesives Prompt L-Pop and Etch&Prime 3.0 were not significantly different from those recorded from smear layer-covered dentin. Although better seals were achieved with One-Up Bond F and Reactmer Bond, fluid conductance at 20 cm hp was significantly higher than the two-step self-etch adhesive UniFil Bond. Osmotic conductance at 0 cm hp were not significantly different from normal fluid conductance at 20 cm hp. The sizes of artificial carious lesions in UniFil Bond were significantly higher irrespective of whether a FR or NFR composite was used. Significant reduction in lesion size occurred in Reactmer Bond with the use of a NFR composite, and even more so with the use of a FR composite.
Itthagarun
Anut
A
Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China.
Tay
Franklin R
FR
Pashley
David H
DH
Wefel
James S
JS
García-Godoy
Franklin
F
Wei
Stephen H Y
SH
D000134:Acid Etching, Dental; D002327:Cariostatic Agents / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003731:Dental Caries / Q000473:pathology / Q000517:prevention & control*; D003804:Dentin / Q000378:metabolism; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D000431:Ethanol / Q000737:chemistry; D005459:Fluorides / Q000737:chemistry; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D006874:Hydrostatic Pressure; D008422:Materials Testing; D008560:Membrane Fluidity; D008567:Membranes, Artificial; D008689:Methacrylates / Q000737:chemistry; D009995:Osmosis; D010539:Permeability; D010710:Phosphates / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D012212:Rheology; D016369:Smear Layer
D002327:Cariostatic Agents; D003188:Composite Resins; D017220:Dentin-Bonding Agents; C469823:Etch&Prime 3.0; D005899:Glass Ionomer Cements; D008567:Membranes, Artificial; C495852:Metafil C; D008689:Methacrylates; C446260:One-Up-Bond F; D010710:Phosphates; C408584:Prompt L-Pop; D019279:Resin Cements; C407402:Unifil Bond; C447779:reactmer bond; D000431:Ethanol; D005459:Fluorides