Characterization of biomodified dentin matrices for potential preventive and reparative therapies

Abstract

Biomodification of existing hard tissue structures, specifically tooth dentin, is an innovative approach proposed to improve the biomechanical and biochemical properties of tissue for potential preventive or reparative/regenerative therapies. The objectives of the study were to systematically characterize dentin matrices biomodified by proanthocyanidin-rich grape seed extract (GSE) and glutaraldehyde (GD). Changes to the biochemistry and biomechanical properties were assessed by several assays to investigate the degree of interactions, biodegradation rates, proteoglycans interaction, and effect of collagen fibril orientation and environmental conditions on the tensile properties. The highest degree of agent-dentin interaction was observed with GSE which exhibited the highest denaturation temperature, regardless of the agent concentration. Biodegradation rates remarkably decreased following biomodification of dentin matrices after 24hs collagenase digestion. A significant decreased in the proteoglycans content of GSE treated samples was observed using a micro-assay for glycosaminoglycans and histological electron microscopy, while no changes were observed for GD and control. Tensile strength properties of GD biomodified dentin matrices were affected by dentin tubule orientation, most likely due to the orientation of the collagen fibrils. Higher and/or increased stability of the tensile properties of GD and GSE-treated samples were observed following exposure to collagenase and 8 month water storage. Biomodification of dentin matrices using chemical agents not only affects the collagen biochemistry; it also involves interaction with proteoglycans. Tissue biomodifiers interact differently with dentin matrices and may provide the tissue with enhanced preventive and restorative/reparative abilities.

Bonding efficiency and durability: current possibilities

“…187,188,189,190,191 Such enzymatic reactions are the basis of tissue stability, viscoelasticity and strength of collagen fibrils. 184,192 In particular, intra-molecular cross-links provide primarily biostability to the collagen molecule, while intermolecular and inter-microfibrillar cross-links enhance mechanical properties, in addition to fibril biostability. 193 Exogenous cross-linking agents have been proposed to mimic physiological cross-links.…”

“…195,205 Their interaction with collagen type I depends on the type of PA, chemical structure, stereochemistry pattern and concentration of these natural extracts. 206,207 PA is a natural cross-linking agent that has been widely studied in recent years due to their ability to biomodify the dentin matrix 184 and enhance its mechanical properties and resistance against biodegradation, finally favoring the resin/dentin bond strengths. 199,204 PA can interact with collagen tissue and induce non-enzymatic collagen cross-linking 193 increasing collagen stiffness and dentin bond strength by keeping the bonding stable over time.…”

“…183 Collagen is a heterotrimeric molecule composed of two α1 and one α2 chains that are comprised of three domains: NH2-terminal (N-telopeptide), the central triple helix and the COOH-terminal non-triple helical (C-telopeptide) domain. 184 Endogenous collagen cross-links are mediated by both non-enzymatic and enzymatic reactions. Non-enzymatic collagen cross-links are mediated by oxidation and glycation processes, 185 while enzymatic reactions happen between the telopeptide and adjacent triple helical chains, 186 which is mediated by chemical reactions through lysyl oxidase covalent bonding.…”

Dentin Biomodification Potential Depends on Polyphenol Source

“…The dentin interactions with polyphenol-rich extracts of Vitis vinifera (grape) and Theobroma cacao (cocoa) seeds have been reported (Castellan et al, 2010Bedran-Russo et al, 2011), albeit with limited extract profiling. Additional potential sources of PACs were selected to expand the scope of the study and help identify the most suitable PAC sources before initiating isolation of bioactive phytoconstituents.…”

Dual function of proanthocyanidins as both MMP inhibitor and crosslinker in dentin biomodification: A literature review

“…It is demonstrated that PA can cause significant drops in glycosaminoglycan (GAG) content in demineralized dentin, that consequently will alter hydration pattern and molecular sieve effect in dentin. All these factors would enhance mechanical properties of resin-dentin inter-diffusion zone 51) . Furthermore, there are several reports indicating that the susceptibility of dense PA treated collagen matrix to creep rupture or cyclic fatigue rupture, would be declined after prolonged intraoral function 52,53) .…”