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Journal ArticleDOI

Strategies to prevent hydrolytic degradation of the hybrid layer—A review

TL;DR: This review will examine both the principles and outcomes of techniques to prevent collagen hydrolysis in dentin-resin interfaces, and shows that enzyme inhibition is a promising approach to improve hybrid layer preservation and bond strength durability.
About: This article is published in Dental Materials.The article was published on 2013-10-01 and is currently open access. It has received 332 citations till now.
Citations
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Journal ArticleDOI
TL;DR: It is presented the case that the organic matrix in caries-affected dentin may not be preserved as intact as previously considered, and this would seriously compromise the matrix ability for intrafibrillar remineralization, which is considered essential in restoring the dentin's mechanical properties.
Abstract: Dentin organic matrix, with type I collagen as the main component, is exposed after demineralization in dentinal caries, erosion or acidic conditioning during adhesive composite restorative treatment. This exposed matrix is prone to slow hydrolytic degradation by host collagenolytic enzymes, matrix metalloproteinases (MMPs) and cysteine cathepsins. Here we review the recent findings demonstrating that inhibition of salivary or dentin endogenous collagenolytic enzymes may provide preventive means against progression of caries or erosion, just as they have been shown to retain the integrity and improve the longevity of resin composite filling bonding to dentin. This paper also presents the case that the organic matrix in caries-affected dentin may not be preserved as intact as previously considered. In partially demineralized dentin, MMPs and cysteine cathepsins with the ability to cleave off the terminal non-helical ends of collagen molecules (telopeptides) may lead to the gradual loss of intramolecular gap areas. This would seriously compromise the matrix ability for intrafibrillar remineralization, which is considered essential in restoring the dentin's mechanical properties. More detailed data of the enzymes responsible and their detailed function in dentin-destructive conditions may not only help to find new and better preventive means, but better preservation of demineralized dentin collagenous matrix may also facilitate true biological remineralization for the better restoration of tooth structural and mechanical integrity and mechanical properties.

440 citations

Journal ArticleDOI
TL;DR: This study critically discusses the available peer-reviewed research concerning the formation and preservation of the hybrid layer (HL), the mechanisms that lead to the degradation of the HL as well as the strategies to prevent it.

261 citations


Cites background from "Strategies to prevent hydrolytic de..."

  • ...In general, these bonds show good durability, but are still prone to loss of bond strength with time [182]....

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  • ...[182] Tjäderhane L, Nascimento FD, Breschi L, Mazzoni A, Tersariol ILS, Geraldeli S, et al....

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Journal ArticleDOI
TL;DR: MMP functions in caries and hybrid layer degradation and the potential therapeutic role of MMP inhibitors for the development of improved intervention strategies for MMP-related oral diseases are explored.
Abstract: Dentin can be described as a biological composite with collagen matrix embedded with nanosized hydroxyapatite mineral crystallites. Matrix metalloproteinases (MMPs) and cysteine cathepsins are families of endopeptidases. Enzymes of both families are present in dentin and collectively capable of degrading virtually all extracellular matrix components. This review describes these enzymes and their presence in dentin, mainly focusing on their role in dentin caries pathogenesis and loss of collagen in the adhesive hybrid layer under composite restorations. MMPs and cysteine cathepsins present in saliva, mineralized dentin, and/or dentinal fluid may affect the dentin caries process at the early phases of demineralization. Changes in collagen and noncollagenous protein structure may participate in observed decreases in mechanical properties of caries-affected dentin and reduce the ability of caries-affected dentin to remineralize. These endogenous enzymes also remain entrapped within the hybrid layer during the resin infiltration process, and the acidic bonding agents themselves (irrespective of whether they are etch-and-rinse or self-etch) can activate these endogenous protease proforms. Since resin impregnation is frequently incomplete, denuded collagen matrices associated with free water (which serves as a collagen cleavage reagent for these endogenous hydrolase enzymes) can be enzymatically disrupted, finally contributing to the degradation of the hybrid layer. There are multiple in vitro and in vivo reports showing that the longevity of the adhesive interface is increased when nonspecific enzyme-inhibiting strategies are used. Different chemicals (i.e., chlorhexidine, galardin, and benzalkonium chloride) or collagen cross-linker agents have been successfully employed as therapeutic primers in the bonding procedure. In addition, the incorporation of enzyme inhibitors (i.e., quaternary ammonium methacrylates) into the resin blends has been recently promoted. This review will describe MMP functions in caries and hybrid layer degradation and explore the potential therapeutic role of MMP inhibitors for the development of improved intervention strategies for MMP-related oral diseases.

241 citations

Journal ArticleDOI
TL;DR: This review looks at the principles, current status, and future of the different techniques designed to prevent the loss of hybrid layer and bond strength in dentin bonding.
Abstract: In dentin bonding, contemporary dental adhesive systems rely on formation of the hybrid layer, a biocomposite containing dentin collagen and polymerized resin adhesive. They are usually able to create at least reasonable integrity of the hybrid layer with high immediate bond strength. However, loss of dentin-bonded interface integrity and bond strength is commonly seen after aging both in vitro and in vivo. This is due to endogenous collagenolytic enzymes, matrix metalloproteinases, and cysteine cathepsins, responsible for the time-dependent loss of hybrid layer collagen. In addition, the hydrophilic nature of adhesive systems creates problems that lead to suboptimal hybrid layers. These problems include, for example, insufficient resin impregnation of dentin, phase separation, and a low rate of polymerization, all of which may reduce the longevity of the bonded interface. Preservation of the collagen matrix integrity by inhibition of endogenous dentin proteases is key to improving dentin bonding durability. Several approaches to retain the integrity of the hybrid layer and to improve the long-term dentin bond strength have been tested. These include the use of enzyme inhibitors, either separately or as incorporated into the adhesive resins; increase of collagen resistance to enzymatic degradation; and elimination of water from the interface to slow down or eliminate hydrolytic loss of the hybrid layer components. This review looks at the principles, current status, and future of the different techniques designed to prevent the loss of hybrid layer and bond strength.

153 citations


Cites background or methods or result from "Strategies to prevent hydrolytic de..."

  • ...Glutaraldehyde is a widely known cross-linker that has been used in dental products, but its cytotoxicity seriously limits its clinical use.(6,120) Carbodiimide hydrochloride has very low cytotoxicity but may have limited cross-linking capacity....

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  • ...Together, these would lead to improved bond durability.(1,6) Currently, however, technique sensitivity and generally long treatment times prohibit ethanol-wet bonding in clinical settings, and more user-friendly and reproducible techniques or materials need to be developed for everyday use....

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  • ...degradation to preserve bond strength, chlorhexidine being the most popular compound.(6) Chlorhex-...

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  • ...Collectively, the in vitro and in vivo data indicate that MDPB-containing adhesives may be superior in the prevention of bond strength loss, when compared to other SE adhesives.(6,60,64,67,104)...

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  • ...integrity of the adhesive interface and the durability of the bond strength.(1,6) Biodegradation of resindentin interfaces also increases bacterial microleakage,(7) leading to undetected secondary caries....

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References
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Journal ArticleDOI
TL;DR: This review describes the members of the matrixin family and discusses substrate specificity, domain structure and function, the activation of proMMPs, the regulation of matrixin activity by tissue inhibitors of metalloproteinases, and their pathophysiological implication.
Abstract: Matrix metalloproteinases (MMPs), also designated matrixins, hydrolyze components of the extracellular matrix. These proteinases play a central role in many biological processes, such as embryogenesis, normal tissue remodeling, wound healing, and angiogenesis, and in diseases such as atheroma, arthritis, cancer, and tissue ulceration. Currently 23 MMP genes have been identified in humans, and most are multidomain proteins. This review describes the members of the matrixin family and discusses substrate specificity, domain structure and function, the activation of proMMPs, the regulation of matrixin activity by tissue inhibitors of metalloproteinases, and their pathophysiological implication.

4,411 citations


"Strategies to prevent hydrolytic de..." refers background in this paper

  • ...Since MMPs require calcium to maintain their tertiary structure and zinc ions for their catalytic activity [42] also in dentin [43], and CHX loses its MMP inhibition in the presence of calcium chloride [3], CHX-related MMP inhibition may be related to its chelating property and calcium ions released by the primer...

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Journal ArticleDOI
TL;DR: This review comprehensively covers literature reports which have investigated specifically the effect of dissolution products of silicate bioactive glasses and glass-ceramics in relation to osteogenesis and angiogenesis and focuses on the ion release kinetics of the materials and the specific effect of the released ionic dissolution products on human cell behaviour.

2,056 citations

Journal ArticleDOI
TL;DR: The aim of this article is to systematically review the ingredients commonly used in current dental adhesives as well as the properties of these ingredients.

1,218 citations

Journal ArticleDOI
TL;DR: Dental polymer networks have been shown to be susceptible to hygroscopic and hydrolytic effects to varying extents dependent upon their chemistry and structure, and these effects on the clinical performance of polymer restoratives is largely unknown.

1,190 citations

Journal ArticleDOI
TL;DR: This study critically discusses the latest peer-reviewed reports related to formation, aging and stability of resin bonding, focusing on the micro and nano-phenomena related to adhesive interface degradation.

1,086 citations