The effects of ethanol on the size-exclusion characteristics of type I dentin collagen to adhesive resin monomers

Abstract

During dentin bonding with etch-and-rinse adhesive systems, phosphoric acid etching of mineralized dentin solubilizes the mineral crystallites and replaces them with bound and unbound water. During the infiltration phase of dentin bonding, solvated adhesive resin comonomers are supposed to replace all of the unbound collagen water and polymerize into copolymers. A recently published review suggested that dental monomers are too large to enter and displace water from tightly-packed collagen molecules. Conversely, recent work from the authors’ laboratory demonstrated that HEMA and TEGDMA freely equilibrate with water-saturated dentin matrices. However, because adhesive blends are solvated in organic solvents, those solvents may remove enough free water to allow collagen molecules to come close enough to exclude adhesive monomer permeation. The present study analyzed the size-exclusion characteristics of dentin collagen, using a gel permeation-like column chromatography technique, filled with dentin powder instead of Sephadex beads as the stationary phase. The elution volumes of different sized test molecules, including adhesive resin monomers, studied in both water-saturated dentin, and again in ethanol-dehydrated dentin powder, showed that adhesive resin monomers can freely diffuse into both hydrated and dehydrated collagen molecules. Under these in vitro conditions, all free and some of the loosely-bound water seems to have been removed by ethanol. These results validate the concept that adhesive resin monomers can permeate tightly-bound water in ethanol-saturated collagen molecules during infiltration by etch-and-rinse adhesives.

Dentin bonding systems: From dentin collagen structure to bond preservation and clinical applications

“…Recent research has revealed that collagen fibrils behave as if they were size-exclusion beads of Sephadex in column chromatography. While molecules with molecular weights smaller than 600 Da can enter collagen, molecules larger than 40 KDa are excluded [196][197][198]. Phosphoric acid, with a molecular weight of 100 Da, is small enough to permeate throughout collagen fibrils, solubilizing both extra-and intrafibrillar mineral, leaving dentin completely demineralized and soft.…”

Bond strengths of three-step etch-and-rinse adhesives to silane contaminated dentin

“…Additionally, ethanol soaking could further remove some amounts of remaining water from the intrafibrillar compartment of the collagen molecules as well as the interfibrillar compartment 34,39) . The penetrating ethanol might improve the permeation of primer components into the intrafibrillar compartment of the collagen molecules 40) . Furthermore, it has been speculated that the MPS molecule (molecular weight=234 Da) dissolved in ethanol can also penetrate into the collagen fibrils, where the silanol group would then react with the hydroxyl groups of the fibrils by forming hydrogen bonds 41) .…”

Effect of polyvinylphosphonic acid on resin-dentin bonds and the cytotoxicity of mouse dental papilla cell-23

“…10,11 The remineralization of hybrid layers with size-exclusion characteristics protected against molecules larger than a 40-kDa protein entering the fibril. 32,33 These prevented activated collagenase from penetrating collagen fibers and contributed to the formation of a nanoscale dentin structure. 34,35 The present study investigated the biomimetic remineralization effect of a treatment containing PVPA on the mechanical properties of interface for a year (Fig.…”