Limits...
The dentin organic matrix - limitations of restorative dentistry hidden on the nanometer scale.

Bertassoni LE, Orgel JP, Antipova O, Swain MV - Acta Biomater (2012)

Bottom Line: Research has shown, however, that this interaction imposes less than desirable long-term prospects for current resin-based dental restorations.Finally, we discuss the relation of these complexly assembled nanostructures with the protease degradative processes driving the low durability of current resin-based dental restorations.We argue in favour of the structural limitations that these complexly organized and inherently hydrated organic structures may impose on the clinical prospects of current hydrophobic and hydrolyzable dental polymers that establish ultrafine contact with the tooth substrate.

View Article: PubMed Central - PubMed

Affiliation: Biomaterials Science Research Unit, Faculty of Dentistry, University of Sydney, United Dental Hospital, NSW, Australia. luiz.bertassoni@sydney.edu.au

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Schematic depiction of a hierarchical view of a hybrid layer and its constituents. (A-i) composite resin, (A-ii) adhesive layer, and (A-iii) monomer infiltrated dentin substrate. (A)–(C) represent increasing magnifications of the currently accepted concept of hybridization, where the D-periodical ∼100 nm diameter dentin collagen fibrils represent the ultimate structures to be impregnated and enveloped (adapted from Powers and Sakaguchi [143]). (D) Collagen fibrils (adapted from Gautieri et al. [144]) interconnected by the proteoglycan decorin (a monomeric representation of the dimeric model based on the available crystal structure of the protein core of decorin [145]). (E) Collagen microfibrillar organization and structure where the C-axis has been compressed for easier visualization (adapted from Orgel et al. [50]). (E-i) Model showing the quasihexagonal lateral packing of the molecular segments. (E-ii) Conformation of the D-staggered collagen segments within a single microfibril. (E-iii) The molecular path of a collagen molecule through successive microfibrils. (E-iv) Enlarged view of the N- (bottom) and C-telopeptide (top) regions of type I collagen. (E-v) Taking several 1D staggered collagen molecules from the collagen packing structure (single molecule shown in C) it is possible to represent the collagen microfibril. (E-vi) Three microfibrils are shown side by side to indicate the probable binding relationship between them.
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f0020: Schematic depiction of a hierarchical view of a hybrid layer and its constituents. (A-i) composite resin, (A-ii) adhesive layer, and (A-iii) monomer infiltrated dentin substrate. (A)–(C) represent increasing magnifications of the currently accepted concept of hybridization, where the D-periodical ∼100 nm diameter dentin collagen fibrils represent the ultimate structures to be impregnated and enveloped (adapted from Powers and Sakaguchi [143]). (D) Collagen fibrils (adapted from Gautieri et al. [144]) interconnected by the proteoglycan decorin (a monomeric representation of the dimeric model based on the available crystal structure of the protein core of decorin [145]). (E) Collagen microfibrillar organization and structure where the C-axis has been compressed for easier visualization (adapted from Orgel et al. [50]). (E-i) Model showing the quasihexagonal lateral packing of the molecular segments. (E-ii) Conformation of the D-staggered collagen segments within a single microfibril. (E-iii) The molecular path of a collagen molecule through successive microfibrils. (E-iv) Enlarged view of the N- (bottom) and C-telopeptide (top) regions of type I collagen. (E-v) Taking several 1D staggered collagen molecules from the collagen packing structure (single molecule shown in C) it is possible to represent the collagen microfibril. (E-vi) Three microfibrils are shown side by side to indicate the probable binding relationship between them.

Mentions: The hybridization of dentin with polymeric bonding agents, originally proposed by Nakabayashi et al. [21], is a fascinating engineering concept that was conceived to enable the micromechanical retention of synthetic polymers on the complex biological substrate that is the tooth. This concept has since its advent represented the most important and far-reaching revolution in contemporary restorative dentistry. However, since the mechanistic concept of hybridization involves the infiltration of adhesive co-monomers (HEMA, triethyleneglycoldimethacrylate (TEGDMA) and, occasionally, urethane dimethacrylate(UDMA)) into demineralized type I collagen fibrils one may ascertain that this paradigm adopts a simplified perspective of the dentin substrate at the sub-fibrillar level, as schematically depicted in Fig. 4. We contend that these intricate supramolecular interactions in collagen offer a variety of structural, molecular and physical constraints against an improved interaction of the synthetic monomers with the dentin substrate on sub-micrometer scales.


The dentin organic matrix - limitations of restorative dentistry hidden on the nanometer scale.

Bertassoni LE, Orgel JP, Antipova O, Swain MV - Acta Biomater (2012)

Schematic depiction of a hierarchical view of a hybrid layer and its constituents. (A-i) composite resin, (A-ii) adhesive layer, and (A-iii) monomer infiltrated dentin substrate. (A)–(C) represent increasing magnifications of the currently accepted concept of hybridization, where the D-periodical ∼100 nm diameter dentin collagen fibrils represent the ultimate structures to be impregnated and enveloped (adapted from Powers and Sakaguchi [143]). (D) Collagen fibrils (adapted from Gautieri et al. [144]) interconnected by the proteoglycan decorin (a monomeric representation of the dimeric model based on the available crystal structure of the protein core of decorin [145]). (E) Collagen microfibrillar organization and structure where the C-axis has been compressed for easier visualization (adapted from Orgel et al. [50]). (E-i) Model showing the quasihexagonal lateral packing of the molecular segments. (E-ii) Conformation of the D-staggered collagen segments within a single microfibril. (E-iii) The molecular path of a collagen molecule through successive microfibrils. (E-iv) Enlarged view of the N- (bottom) and C-telopeptide (top) regions of type I collagen. (E-v) Taking several 1D staggered collagen molecules from the collagen packing structure (single molecule shown in C) it is possible to represent the collagen microfibril. (E-vi) Three microfibrils are shown side by side to indicate the probable binding relationship between them.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3473357&req=5

f0020: Schematic depiction of a hierarchical view of a hybrid layer and its constituents. (A-i) composite resin, (A-ii) adhesive layer, and (A-iii) monomer infiltrated dentin substrate. (A)–(C) represent increasing magnifications of the currently accepted concept of hybridization, where the D-periodical ∼100 nm diameter dentin collagen fibrils represent the ultimate structures to be impregnated and enveloped (adapted from Powers and Sakaguchi [143]). (D) Collagen fibrils (adapted from Gautieri et al. [144]) interconnected by the proteoglycan decorin (a monomeric representation of the dimeric model based on the available crystal structure of the protein core of decorin [145]). (E) Collagen microfibrillar organization and structure where the C-axis has been compressed for easier visualization (adapted from Orgel et al. [50]). (E-i) Model showing the quasihexagonal lateral packing of the molecular segments. (E-ii) Conformation of the D-staggered collagen segments within a single microfibril. (E-iii) The molecular path of a collagen molecule through successive microfibrils. (E-iv) Enlarged view of the N- (bottom) and C-telopeptide (top) regions of type I collagen. (E-v) Taking several 1D staggered collagen molecules from the collagen packing structure (single molecule shown in C) it is possible to represent the collagen microfibril. (E-vi) Three microfibrils are shown side by side to indicate the probable binding relationship between them.
Mentions: The hybridization of dentin with polymeric bonding agents, originally proposed by Nakabayashi et al. [21], is a fascinating engineering concept that was conceived to enable the micromechanical retention of synthetic polymers on the complex biological substrate that is the tooth. This concept has since its advent represented the most important and far-reaching revolution in contemporary restorative dentistry. However, since the mechanistic concept of hybridization involves the infiltration of adhesive co-monomers (HEMA, triethyleneglycoldimethacrylate (TEGDMA) and, occasionally, urethane dimethacrylate(UDMA)) into demineralized type I collagen fibrils one may ascertain that this paradigm adopts a simplified perspective of the dentin substrate at the sub-fibrillar level, as schematically depicted in Fig. 4. We contend that these intricate supramolecular interactions in collagen offer a variety of structural, molecular and physical constraints against an improved interaction of the synthetic monomers with the dentin substrate on sub-micrometer scales.

Bottom Line: Research has shown, however, that this interaction imposes less than desirable long-term prospects for current resin-based dental restorations.Finally, we discuss the relation of these complexly assembled nanostructures with the protease degradative processes driving the low durability of current resin-based dental restorations.We argue in favour of the structural limitations that these complexly organized and inherently hydrated organic structures may impose on the clinical prospects of current hydrophobic and hydrolyzable dental polymers that establish ultrafine contact with the tooth substrate.

View Article: PubMed Central - PubMed

Affiliation: Biomaterials Science Research Unit, Faculty of Dentistry, University of Sydney, United Dental Hospital, NSW, Australia. luiz.bertassoni@sydney.edu.au

Show MeSH
Related in: MedlinePlus