Dentine proteoglycans: composition, ultrastructure and functions

Goldberg, Michel; Takagi, Minoru

doi:10.1007/bf00188045

Cited by 47 publications

(67 citation statements)

References 121 publications

(112 reference statements)

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“…After collagen, proteoglycans and their glycosaminoglycan side chains represent the organic components with greater structural relevance [38] in the dentin matrix [39]. Decorin and biglycan are the most prominent proteoglycans in mineralized tissues, and their relevance in collagen fibrillogenesis has been extensively described in the literature.…”

Section: Discussionmentioning

confidence: 99%

Removal of dentin non-collagenous structures results in the unraveling of microfibril bundles in collagen type I

Bertassoni

Swain

2016

Connective Tissue Research

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Aims: The structural organization of collagen from mineralized tissues, such as dentin and bone, has been a topic of debate in the recent literature. Recent reports have presented novel interpretations of the complexity of collagen type I at different hierarchical levels and in different tissues. Here we investigate the nanostructural organization of demineralized dentin collagen following the digestion of non-collagenous components with a trypsin enzyme. Materials and Methods: Dentin specimens were obtained from healthy third-molars, cut into small cubes and polished down to 1 μm roughness. Samples were then demineralized with 10% citric acid for 2 min. Selected specimens were further treated with a solution containing 1 mg/ml trypsin for 48 hours at 37ºC (pH 7.9 – 9.0). Both untreated and trypsin digested samples were analyzed using SDS-PAGE, Field Emission Scanning Electron Microscopy (FE-SEM), and nanoindentation, where surface hardness and creep properties where compared before and after treatments. Results: FE-SEM images of demineralized dentin showed the banded morphology of D-periodical collagen type I, which upon enzymatic digestion with trypsin appeared to dissociate longitudinally, consistently unraveling ~20 nm structures (microfibril bundles). Such nanoscale structures, which we call microfibril bundles, to the best of our knowledge, have not been characterized in dentin previously. Mechanical characterization via nanoindentation showed that the unraveling of such microfibril bundles affected the creep displacement and creep rate of demineralized dentin. Conclusion: In summary, our results provide novel evidence of the organization of collagen type I from dentin, which may have important implications for the interaction of dental materials with the organic dentin matrix and the mechanical properties of mineralized tissues.

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Section: Discussionmentioning

confidence: 99%

Removal of dentin non-collagenous structures results in the unraveling of microfibril bundles in collagen type I

Bertassoni

Swain

2016

Connective Tissue Research

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“…The random arrangement of collagen fibrils in dentin matrices increases the interstitial unbound water content. Both tendon and dentin contain proteoglycans between collagen fibrils [41,42]. Acid-etching of dentin with 35% phosphoric acid apparently denatures dentin proteoglycans after 15 s of etching [42].…”

Section: Discussionmentioning

confidence: 99%

“…However, bound water must also bind to proteoglycans [41,42] and other non-collagenous proteins, including MMPs and cathepsins. It is unlikely that water bound to protease hydrolases can participate in hydrolysis of collagen.…”

Section: Discussionmentioning

confidence: 99%

Water distribution in dentin matrices: Bound vs. unbound water

et al. 2015

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Objectives This work measured the amount of bound versus unbound water in completely-demineralized dentin. Methods Dentin beams prepared from extracted human teeth were completely demineralized, rinsed and dried to constant mass. They were rehydrated in 41% relative humidity (RH), while gravimetrically measuring their mass increase until the first plateau was reached at 0.064 (vacuum) or 0.116 g H2O/g dry mass (Drierite). The specimens were then exposed to 60% RH until attaining the second plateau at 0.220 (vacuum) or 0.191 g H2O/g dry mass (Drierite), and subsequently exposed to 99% RH until attaining the third plateau at 0.493 (vacuum) or 0.401 g H2O/g dry mass (Drierite). Results Exposure of the first layer of bound water to 0% RH for 5 min produced a −0.3% loss of bound water; in the second layer of bound water it caused a −3.3% loss of bound water; in the third layer it caused a −6% loss of bound water. Immersion in 100% ethanol or acetone for 5 min produced a 2.8 and 1.9% loss of bound water from the first layer, respectively; it caused a −4 and −7% loss of bound water in the second layer, respectively; and a −17 and −23% loss of bound water in the third layer.. Bound water represented 21–25% of total dentin water. Chemical dehydration of water-saturated dentin with ethanol/acetone for 1 min only removed between 25 to 35% of unbound water, respectively. Significance Attempts to remove bound water by evaporation were not very successful. Chemical dehydration with 100% acetone was more successful than 100% ethanol especially the third layer of bound water. Since unbound water represents between 75–79% of total matrix water, the more such water can be removed, the more resin can be infiltrated.

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“…Indeed, the magnitude of and abiding retention of CHX observed in the current study for partially- (PDD) and, especially, totally-demineralized dentin specimens (TDD) (Table 1) indicates that CHX can markedly interact with organic components of dentin matrix. Again, in this case, it is assumed that the nature of CHX-dentin matrix interaction is governed by electrostatic forces, wherein protonated CHX presumably reacts with negatively-charged molecules of dentin matrix, such as with certain anionic organic domains ( - COOH and/or - OH) of collagen or even with anionic moieties of glycosaminoglycans [33] that in turn are closely related to collagen fibrils [34,35]. …”

Section: Discussionmentioning

confidence: 99%

Substantivity of chlorhexidine to human dentin

Carrilho¹,

Carvalho²,

Sousa³

et al. 2010

Dental Materials

177

123

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Objectives-To better comprehend the role of CHX in the preservation of resin-dentin bonds, this study investigated the substantivity of CHX to human dentin.Material and Methods-Dentin disks (n= 45) were obtained from the mid-coronal portion of human third molars. One-third of dentin disks were kept mineralized (MD), while the other twothirds had one of the surfaces partially demineralized with 37% phosphoric acid for 15 s (PDD) or they were totally demineralized with 10% phosphoric acid (TDD). Disks of hydroxyapatite (HA) were also prepared. Specimens were treated with: 1) 10 μL of distilled water (controls), 2) 10 μL of 0.2% chlorhexidine diacetate (0.2% CHX) or 3) 10 μL of 2% chlorhexidine diacetate (2% CHX). Then, they were incubated in 1 mL of PBS (pH 7.4, 37 °C). Substantivity was evaluated as a function of the CHX-applied dose after: 0.5h, 1h, 3h, 6h, 24h, 168h (1wk), 672h (4wks) and 1344h (8wks) of incubation. CHX concentration in eluates was spectrophotometrically analyzed at 260 nm.Results-Significant amounts of CHX remained retained in dentin substrates (MD, PPD or TDD), independent on the CHX-applied dose or time of incubation (p<0.05). High amounts of retained CHX onto HA were observed only for specimens treated with the highest concentration of CHX (2%) (p<0.05). Conclusion-The outstanding substantivity of CHX to dentin and its reported effect on the inhibition of dentinal proteases may explain why CHX can prolong the durability of resin-dentin bonds.

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Dentine proteoglycans: composition, ultrastructure and functions

Cited by 47 publications

References 121 publications

Removal of dentin non-collagenous structures results in the unraveling of microfibril bundles in collagen type I

Removal of dentin non-collagenous structures results in the unraveling of microfibril bundles in collagen type I

Water distribution in dentin matrices: Bound vs. unbound water

Substantivity of chlorhexidine to human dentin

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