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David H Pashley - One of the best experts on this subject based on the ideXlab platform.
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effect of a one step self etch adhesive on endogenous dentin matrix metalloproteinases
European Journal of Oral Sciences, 2017Co-Authors: Fabianni Magalhaes Apolonio, Frankli R Tay, Valeria Angeloni, Annalisa Mazzoni, Vicente De Paulo Aragao Saboia, Polliana Mendes Candia Scaffa, Spartaco Santi, David H Pashley, Luca BreschiAbstract:Degradation of the Hybrid Layer created in dentin by dentin adhesives is caused by enzyme activities present within the dentin matrix that destroy unprotected collagen fibrils. The aim of the present study was to evaluate the effect of a one-step self-etch adhesive system on dentinal matrix metalloproteinases 2 and 4 (MMP-2 and MMP-9, respectively) using in situ zymography and an enzymatic activity assay. The null hypothesis tested was that there are no differences in the activities of dentinal MMPs before and after treatment with a one-step adhesive system. The MMP-2 and MMP-9 activities in dentin treated with the one-step adhesive, Adper Easy Bond, were quantified using an enzymatic activity assay system. The MMP activities within the Hybrid Layer created by the one-step adhesive tested were also evaluated using in situ zymography. The enzymatic assay revealed an increase in MMP-2 and MMP-9 activities after treatment with adhesive. In situ zymography indicated that gelatinolytic activity is present within the Hybrid Layer created with the one-step self-etch adhesive. The host-derived gelatinases were localized within the Hybrid Layer and remained active after the bonding procedure. It is concluded that the one-step self-etch adhesive investigated activates endogenous MMP-2 and MMP-9 with the dentin matrix, which may cause collagen degradation over time.
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role of dentin mmps in caries progression and bond stability
Journal of Dental Research, 2015Co-Authors: Annalisa Mazzoni, Roberto Di Lenarda, Leo Tjaderhane, David H Pashley, Vittorio Checchi, Tuula Salo, Luca BreschiAbstract: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.
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ethanol wet bonding and chlorhexidine improve resin dentin bond durability quantitative analysis using raman spectroscopy
Journal of Adhesive Dentistry, 2014Co-Authors: S Talungchit, Saulo Geraldeli, Julie L P Jessop, D S Cobb, Fang Qian, David H PashleyAbstract:PURPOSE: To directly test the effectiveness of ethanol-wet bonding (EW) in improving monomer infiltration into demineralized dentin through quantitative measurement of bis-GMA and TEG-DMA molar concentrations within Hybrid Layers, and to comprehensively evaluate the effect of EW and chlorhexidine on durability of resin-dentin bonds compared to conventional water-wet bonding (WW). MATERIALS AND METHODS: A three-step etch-and-rinse adhesive (70% bis-GMA/28.75%TEG-DMA) was applied to coronal dentin using a clinically relevant ethanol-wet bonding protocol (EW) or the conventional water-wet bonding (WW) technique. Bis-GMA and TEG-DMA molar concentrations at various positions across the resin/dentin interfaces formed by EW and WW were measured using micro-Raman spectroscopy. The experiment was repeated at the same positions after 7-month storage in phosphate buffer solution containing 0.1% sodium azide. The μTBS and Hybrid Layer morphology (TEM) of bonding groups with and without chlorhexidine application were compared immediately and after 1-year storage in terms of nanoleakage, collagen fibril diameter, collagen interfibrillar width, and Hybrid Layer thickness. RESULTS: Specimens bonded with EW showed significantly higher monomer molar concentrations and μTBS throughout the Hybrid Layer immediately and after storage, providing direct evidence of superior infiltration of hydrophobic monomers in EW compared to WW. Microscopically, EW maintained interfibrillar width and Hybrid Layer thickness for resin infiltration and retention. The application of chlorhexidine further preserved collagen integrity and limited the degree of nanoleakage in EW after 1-year storage. CONCLUSION: EW enhances infiltration of hydrophobic monomers into demineralized dentin. The results suggest that a more durable resin-dentin bond may be achieved with combined usage of a clinically relevant EW and chlorhexidine.
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electrical properties of resin monomers used in restorative dentistry
Dental Materials, 2012Co-Authors: Marco Breschi, Annalisa Mazzoni, David H Pashley, D Fabiani, Leonardo Sandrolini, Martino Colonna, Laura Sisti, Micaela Vannini, Alessandra Ruggeri, Luca BreschiAbstract:Objectives The application of an electric field has been shown to positively influence the impregnation of the resin monomers currently used in dentin bonding systems during Hybrid Layer formation. This study presents an experimental characterization of the electrical properties of these monomers with the aim of both correlating them to their chemical structures and seeking an insight into the mechanisms of the monomer migration under an applied electric field.
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inhibition of endogenous dentin matrix metalloproteinases by ethylenediaminetetraacetic acid
Journal of Endodontics, 2012Co-Authors: Jeremy M Thompso, Frankli R Tay, Stephanie J Sidow, Kathlee Mcnally, Kimberly Lindsey, James L Orke, Mohammed Elsalanty, Kelli A Agee, David H PashleyAbstract:Abstract Introduction Endogenous dentin matrix metalloproteinases (MMPs) contribute to extracellular collagen matrix degradation in Hybrid Layers after adhesive dentin bonding procedures. Endodontic irrigants, including chlorhexidine and ethylenediaminetetraacetic acid (EDTA), might help protect the Hybrid Layer from this process. The objective of the present study was to determine the exposure time necessary for EDTA to inactivate endogenous MMP activity in human dentin. Methods Dentin beams (2 × 1 × 3 mm) were prepared from mid-coronal dentin of extracted third molars. The beams were demineralized in 10 wt% phosphoric acid, which also activated endogenous MMPs, and were divided into 4 experimental groups on the basis of exposure time to 17% EDTA (0, 1, 2, or 5 minutes). A generic colorimetric MMP assay measured MMP activity via absorbance at 412 nm. Data were evaluated by Kruskal-Wallis analysis of variance, followed by Dunn pair-wise comparisons at α = 0.05. Results All exposure times resulted in significant inhibition ( P Conclusions Seventeen percent EDTA significantly inhibits endogenous MMP activity of human dentin within 1–2 minutes. This might minimize Hybrid Layer degradation after resin bonding procedures in the root canal space.
Salvatore Sauro - One of the best experts on this subject based on the ideXlab platform.
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a zn doped etch and rinse adhesive may improve the mechanical properties and the integrity at the bonded dentin interface
Dental Materials, 2013Co-Authors: Manuel Toledano, Salvatore Sauro, Inmaculada Cabello, T F Watson, Raquel OsorioAbstract:Abstract Objective The objective of the study was to determine if zinc-doped etch-and-rinse dentin adhesive may induce therapeutic effects within the resin–dentin interface. Methods Human acid-etched dentin was infiltrated with Adper™ Single Bond Plus (SB, 3M ESPE, St. Paul, MN, USA), SB doped with 10 wt.% ZnO nanoparticles (ZnO-SB) or SB doped with 2 wt.% ZnCl 2 (ZnCl 2 -SB). AFM/nanoindentation analysis was performed on fully hydrated specimens to evaluate the nanomechanical properties ( H i : hardness; E i : modulus of elasticity) across the resin–dentin interface after different SBF storage periods (24 h, 1 m, 3 m). Confocal laser microscopy (CLSM) was used to evaluate the ultramorphology and micropermeability at 24 h and 3 m of SBF storage. Results SB control specimens exhibited a decrease in H i in the Hybrid Layer (HL) and bottom of the Hybrid Layer (BHL) and a decrease in E i in the HL after 3 m of SBF storage, indicating that severe degradation occurred in the control interface. ZnO-SB bonded specimens preserved the initial H i and E i at the HL and BHL subsequent SBF storage; ZnCl 2 -SB bonded specimens showed a decrease in E i , in the HL over time. CLSM analysis confirmed that both Zn-doped adhesives were able to preserve the integrity of the HL. Significance Specific formulation of Zn-doped etch-and-rinse adhesives may offer the possibility to maintain the nano-mechanical properties along the dentin-bonded interface by inhibiting dentin MMPs and by protective mineral crystals formation within the resin–dentin interface. Clinical advantages may be expected by preserving and improving the integrity of the Hybrid Layer when Zn-doped adhesives are employed.
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two photon laser confocal microscopy of micropermeability of resin dentin bonds made with water or ethanol wet bonding
Journal of Biomedical Materials Research Part B, 2008Co-Authors: Salvatore Sauro, Francesco Mannocci, T F Watson, Katsuya Miyake, Bradford P Huffman, David H PashleyAbstract:This study evaluated the micropermeability of six etch-and-rinse adhesives bonded to dentin. There were two principal groups: wet bonding with water or wet bonding with absolute ethyl alcohol. After bonding and the creation of composite build-ups, the pulp chambers were filled with 0.1% Lucifer Yellow. The contents of the pulp chamber were kept under 20 cm H2O pressure to simulate pulpal pressure for 3 h. The specimens were vertically sectioned into multiple 0.5 mm thick slabs that were polished and then examined in a two-photon confocal laser scanning microscope (TPCLSM). The results showed that specimens bonded with adhesives using the water wet-bonding condition all showed tracer taken up uniformly by the Hybrid Layer. This uptake of fluorescent tracer into the Hybrid Layer was quantified by computer software. The most hydrophobic experimental resins showed the highest fluorescent tracer uptake (ca. 1800 ± 160 arbitrary fluorescent units/std. surface area). The most hydrophilic experimental resins showed the lowest tracer uptake into water-saturated Hybrid Layers (ca. 1000 ± 100 units). When ethanol wet-bonding was used, significantly less tracer was seen in Hybrid Layers. The most hydrophilic experimental resins and Single Bond Plus only took up about 100 ± 20 units. Clearly, ethanol wet-bonding seals dentin significantly better than water-wet dentin regardless of the adhesive in etch-and-rinse systems.
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two photon laser confocal microscopy of micropermeability of resin dentin bonds made with water or ethanol wet bonding
Journal of Biomedical Materials Research Part B, 2008Co-Authors: Salvatore Sauro, Frankli R Tay, Francesco Mannocci, T F Watson, Katsuya Miyake, Bradford P Huffman, David H PashleyAbstract:This study evaluated the micropermeability of six etch-and-rinse adhesives bonded to dentin. There were two principal groups: wet bonding with water or wet bonding with absolute ethyl alcohol. After bonding and the creation of composite build-ups, the pulp chambers were filled with 0.1% lucifer yellow. The contents of the pulp chamber were kept under 20 cm H(2)O pressure to simulate pulpal pressure for 3 h. The specimens were vertically sectioned into multiple 0.5-mm thick slabs that were polished and then examined using a two-photon confocal laser scanning microscope (TPCLSM). The results showed that specimens bonded with adhesives using the water wet-bonding condition all showed tracer taken up uniformly by the Hybrid Layer. This uptake of fluorescent tracer into the Hybrid Layer was quantified by computer software. The most hydrophobic experimental resins showed the highest fluorescent tracer uptake (ca. 1800 +/- 160 arbitrary fluorescent units/std. surface area). The most hydrophilic experimental resins showed the lowest tracer uptake into water-saturated Hybrid Layers. When ethanol wet-bonding was used, significantly less fluorescent tracer was seen in Hybrid Layers. The most hydrophilic experimental resins and Single Bond Plus showed little micropermeability. Clearly, ethanol wet-bonding seals dentin significantly better than water-wet dentin regardless of the adhesive in etch-and-rinse systems.
Luca Breschi - One of the best experts on this subject based on the ideXlab platform.
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effect of a one step self etch adhesive on endogenous dentin matrix metalloproteinases
European Journal of Oral Sciences, 2017Co-Authors: Fabianni Magalhaes Apolonio, Frankli R Tay, Valeria Angeloni, Annalisa Mazzoni, Vicente De Paulo Aragao Saboia, Polliana Mendes Candia Scaffa, Spartaco Santi, David H Pashley, Luca BreschiAbstract:Degradation of the Hybrid Layer created in dentin by dentin adhesives is caused by enzyme activities present within the dentin matrix that destroy unprotected collagen fibrils. The aim of the present study was to evaluate the effect of a one-step self-etch adhesive system on dentinal matrix metalloproteinases 2 and 4 (MMP-2 and MMP-9, respectively) using in situ zymography and an enzymatic activity assay. The null hypothesis tested was that there are no differences in the activities of dentinal MMPs before and after treatment with a one-step adhesive system. The MMP-2 and MMP-9 activities in dentin treated with the one-step adhesive, Adper Easy Bond, were quantified using an enzymatic activity assay system. The MMP activities within the Hybrid Layer created by the one-step adhesive tested were also evaluated using in situ zymography. The enzymatic assay revealed an increase in MMP-2 and MMP-9 activities after treatment with adhesive. In situ zymography indicated that gelatinolytic activity is present within the Hybrid Layer created with the one-step self-etch adhesive. The host-derived gelatinases were localized within the Hybrid Layer and remained active after the bonding procedure. It is concluded that the one-step self-etch adhesive investigated activates endogenous MMP-2 and MMP-9 with the dentin matrix, which may cause collagen degradation over time.
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mechanisms of degradation of the Hybrid Layer in adhesive dentistry and therapeutic agents to improve bond durability a literature review
Dental Materials, 2016Co-Authors: Andrea Frassetto, Luca Breschi, Gabriele Marchesi, David Henry Pashley, Roberto Di Lenarda, Gianluca Turco, Milena CadenaroAbstract:Abstract Objective Success in adhesive dentistry means long lasting restorations. However, there is substantial evidence that this ideal objective is not always achieved. Current research in this field aims at increasing the durability of resin–dentin bonds. The objective of this paper is to examine the fundamental processes responsible for the aging mechanisms involved in the degradation of resin-bonded interfaces and the potential approaches to prevent and counteract this degradation. Methods PubMed searches on the Hybrid Layer degradation were carried out. Keywords were chosen to assess Hybrid Layer degradation for providing up-dated information on the basis of scientific coherence with the research objective. Approaches to prevent and counteract this degradation were also reviewed. Results 148 peer-review articles in the English language between 1982 and 2015 were reviewed. Literature shows that resin–dentin bond degradation is a complex process, involving the hydrolysis of both the resin and the collagen fibril phases contained within the Hybrid Layer. Collagen fibers become vulnerable to mechanical and hydraulic fatigue, as well as degradation by host-derived proteases with collagenolytic activity (matrix metalloproteinases and cysteine cathepsins). Inhibition of the collagenolytic activity and the use of cross-linking agents are the two main strategies to increase the resistance of the Hybrid Layer to enzymatic degradation. Significance This review analyzes the issues regarding the durability of the adhesive interface, and the techniques to create stable resin–dentin bonds able to resist the collagenolytic hydrolysis that are currently studied.
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role of dentin mmps in caries progression and bond stability
Journal of Dental Research, 2015Co-Authors: Annalisa Mazzoni, Roberto Di Lenarda, Leo Tjaderhane, David H Pashley, Vittorio Checchi, Tuula Salo, Luca BreschiAbstract: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.
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electrical properties of resin monomers used in restorative dentistry
Dental Materials, 2012Co-Authors: Marco Breschi, Annalisa Mazzoni, David H Pashley, D Fabiani, Leonardo Sandrolini, Martino Colonna, Laura Sisti, Micaela Vannini, Alessandra Ruggeri, Luca BreschiAbstract:Objectives The application of an electric field has been shown to positively influence the impregnation of the resin monomers currently used in dentin bonding systems during Hybrid Layer formation. This study presents an experimental characterization of the electrical properties of these monomers with the aim of both correlating them to their chemical structures and seeking an insight into the mechanisms of the monomer migration under an applied electric field.
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implication of ethanol wet bonding in Hybrid Layer remineralization
Journal of Dental Research, 2010Co-Authors: Lisha Gu, Luca Breschi, Leo Tjaderhane, Kyoung Kyu Choi, David Henry PashleyAbstract:During mineralization, unbound water within the collagen matrix is replaced by apatite. This study tested the null hypothesis that there is no difference in the status of in vitro biomimetic remineralization of Hybrid Layers, regardless of their moisture contents. Acid-etched dentin was bonded with One-Step with ethanol-wet-bonding, water-wet-bonding, and water-overwet-bonding protocols. Composite-dentin slabs were subjected to remineralization for 1-4 months in a medium containing dual biomimetic analogs, with set Portland cement as the calcium source and characterized by transmission electron microscopy. Remineralization was either non-existent or restricted to the intrafibrillar mode in ethanol-wet-bonded specimens. Extensive intrafibrillar and interfibrillar remineralization was observed in water-wet-bonded specimens. Water-overwet specimens demonstrated partial remineralization of Hybrid Layers and precipitation of mineralized plates within water channels. The use of ethanol-wet-bonding substantiates that biomimetic remineralization is a progressive dehydration process that replaces residual water in Hybrid Layers with apatite crystallites.
T F Watson - One of the best experts on this subject based on the ideXlab platform.
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a zn doped etch and rinse adhesive may improve the mechanical properties and the integrity at the bonded dentin interface
Dental Materials, 2013Co-Authors: Manuel Toledano, Salvatore Sauro, Inmaculada Cabello, T F Watson, Raquel OsorioAbstract:Abstract Objective The objective of the study was to determine if zinc-doped etch-and-rinse dentin adhesive may induce therapeutic effects within the resin–dentin interface. Methods Human acid-etched dentin was infiltrated with Adper™ Single Bond Plus (SB, 3M ESPE, St. Paul, MN, USA), SB doped with 10 wt.% ZnO nanoparticles (ZnO-SB) or SB doped with 2 wt.% ZnCl 2 (ZnCl 2 -SB). AFM/nanoindentation analysis was performed on fully hydrated specimens to evaluate the nanomechanical properties ( H i : hardness; E i : modulus of elasticity) across the resin–dentin interface after different SBF storage periods (24 h, 1 m, 3 m). Confocal laser microscopy (CLSM) was used to evaluate the ultramorphology and micropermeability at 24 h and 3 m of SBF storage. Results SB control specimens exhibited a decrease in H i in the Hybrid Layer (HL) and bottom of the Hybrid Layer (BHL) and a decrease in E i in the HL after 3 m of SBF storage, indicating that severe degradation occurred in the control interface. ZnO-SB bonded specimens preserved the initial H i and E i at the HL and BHL subsequent SBF storage; ZnCl 2 -SB bonded specimens showed a decrease in E i , in the HL over time. CLSM analysis confirmed that both Zn-doped adhesives were able to preserve the integrity of the HL. Significance Specific formulation of Zn-doped etch-and-rinse adhesives may offer the possibility to maintain the nano-mechanical properties along the dentin-bonded interface by inhibiting dentin MMPs and by protective mineral crystals formation within the resin–dentin interface. Clinical advantages may be expected by preserving and improving the integrity of the Hybrid Layer when Zn-doped adhesives are employed.
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two photon laser confocal microscopy of micropermeability of resin dentin bonds made with water or ethanol wet bonding
Journal of Biomedical Materials Research Part B, 2008Co-Authors: Salvatore Sauro, Francesco Mannocci, T F Watson, Katsuya Miyake, Bradford P Huffman, David H PashleyAbstract:This study evaluated the micropermeability of six etch-and-rinse adhesives bonded to dentin. There were two principal groups: wet bonding with water or wet bonding with absolute ethyl alcohol. After bonding and the creation of composite build-ups, the pulp chambers were filled with 0.1% Lucifer Yellow. The contents of the pulp chamber were kept under 20 cm H2O pressure to simulate pulpal pressure for 3 h. The specimens were vertically sectioned into multiple 0.5 mm thick slabs that were polished and then examined in a two-photon confocal laser scanning microscope (TPCLSM). The results showed that specimens bonded with adhesives using the water wet-bonding condition all showed tracer taken up uniformly by the Hybrid Layer. This uptake of fluorescent tracer into the Hybrid Layer was quantified by computer software. The most hydrophobic experimental resins showed the highest fluorescent tracer uptake (ca. 1800 ± 160 arbitrary fluorescent units/std. surface area). The most hydrophilic experimental resins showed the lowest tracer uptake into water-saturated Hybrid Layers (ca. 1000 ± 100 units). When ethanol wet-bonding was used, significantly less tracer was seen in Hybrid Layers. The most hydrophilic experimental resins and Single Bond Plus only took up about 100 ± 20 units. Clearly, ethanol wet-bonding seals dentin significantly better than water-wet dentin regardless of the adhesive in etch-and-rinse systems.
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two photon laser confocal microscopy of micropermeability of resin dentin bonds made with water or ethanol wet bonding
Journal of Biomedical Materials Research Part B, 2008Co-Authors: Salvatore Sauro, Frankli R Tay, Francesco Mannocci, T F Watson, Katsuya Miyake, Bradford P Huffman, David H PashleyAbstract:This study evaluated the micropermeability of six etch-and-rinse adhesives bonded to dentin. There were two principal groups: wet bonding with water or wet bonding with absolute ethyl alcohol. After bonding and the creation of composite build-ups, the pulp chambers were filled with 0.1% lucifer yellow. The contents of the pulp chamber were kept under 20 cm H(2)O pressure to simulate pulpal pressure for 3 h. The specimens were vertically sectioned into multiple 0.5-mm thick slabs that were polished and then examined using a two-photon confocal laser scanning microscope (TPCLSM). The results showed that specimens bonded with adhesives using the water wet-bonding condition all showed tracer taken up uniformly by the Hybrid Layer. This uptake of fluorescent tracer into the Hybrid Layer was quantified by computer software. The most hydrophobic experimental resins showed the highest fluorescent tracer uptake (ca. 1800 +/- 160 arbitrary fluorescent units/std. surface area). The most hydrophilic experimental resins showed the lowest tracer uptake into water-saturated Hybrid Layers. When ethanol wet-bonding was used, significantly less fluorescent tracer was seen in Hybrid Layers. The most hydrophilic experimental resins and Single Bond Plus showed little micropermeability. Clearly, ethanol wet-bonding seals dentin significantly better than water-wet dentin regardless of the adhesive in etch-and-rinse systems.
David Henry Pashley - One of the best experts on this subject based on the ideXlab platform.
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mechanisms of degradation of the Hybrid Layer in adhesive dentistry and therapeutic agents to improve bond durability a literature review
Dental Materials, 2016Co-Authors: Andrea Frassetto, Luca Breschi, Gabriele Marchesi, David Henry Pashley, Roberto Di Lenarda, Gianluca Turco, Milena CadenaroAbstract:Abstract Objective Success in adhesive dentistry means long lasting restorations. However, there is substantial evidence that this ideal objective is not always achieved. Current research in this field aims at increasing the durability of resin–dentin bonds. The objective of this paper is to examine the fundamental processes responsible for the aging mechanisms involved in the degradation of resin-bonded interfaces and the potential approaches to prevent and counteract this degradation. Methods PubMed searches on the Hybrid Layer degradation were carried out. Keywords were chosen to assess Hybrid Layer degradation for providing up-dated information on the basis of scientific coherence with the research objective. Approaches to prevent and counteract this degradation were also reviewed. Results 148 peer-review articles in the English language between 1982 and 2015 were reviewed. Literature shows that resin–dentin bond degradation is a complex process, involving the hydrolysis of both the resin and the collagen fibril phases contained within the Hybrid Layer. Collagen fibers become vulnerable to mechanical and hydraulic fatigue, as well as degradation by host-derived proteases with collagenolytic activity (matrix metalloproteinases and cysteine cathepsins). Inhibition of the collagenolytic activity and the use of cross-linking agents are the two main strategies to increase the resistance of the Hybrid Layer to enzymatic degradation. Significance This review analyzes the issues regarding the durability of the adhesive interface, and the techniques to create stable resin–dentin bonds able to resist the collagenolytic hydrolysis that are currently studied.
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ethanol wet bonding challenges current anti degradation strategy
Journal of Dental Research, 2010Co-Authors: Fernanda Tranchesi Sadek, Roberto Ruggiero Braga, Antonio Muench, David Henry PashleyAbstract:The long-term effectiveness of chlorhexidine as a matrix metalloproteinase (MMP) inhibitor may be compromised when water is incompletely removed during dentin bonding. This study challenged this anti-bond degradation strategy by testing the null hypothesis that wet-bonding with water or ethanol has no effect on the effectiveness of chlorhexidine in preventing Hybrid Layer degradation over an 18-month period. Acid-etched dentin was bonded under pulpal pressure simulation with Scotchbond MP and Single Bond 2, with water wet-bonding or with a hydrophobic adhesive with ethanol wet-bonding, with or without pre-treatment with chlorhexidine diacetate (CHD). Resin-dentin beams were prepared for bond strength and TEM evaluation after 24 hrs and after aging in artificial saliva for 9 and 18 mos. Bonds made to ethanol-saturated dentin did not change over time with preservation of Hybrid Layer integrity. Bonds made to CHD pre-treated acid-etched dentin with commercial adhesives with water wet-bonding were preserved a...
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implication of ethanol wet bonding in Hybrid Layer remineralization
Journal of Dental Research, 2010Co-Authors: Lisha Gu, Luca Breschi, Leo Tjaderhane, Kyoung Kyu Choi, David Henry PashleyAbstract:During mineralization, unbound water within the collagen matrix is replaced by apatite. This study tested the null hypothesis that there is no difference in the status of in vitro biomimetic remineralization of Hybrid Layers, regardless of their moisture contents. Acid-etched dentin was bonded with One-Step with ethanol-wet-bonding, water-wet-bonding, and water-overwet-bonding protocols. Composite-dentin slabs were subjected to remineralization for 1-4 months in a medium containing dual biomimetic analogs, with set Portland cement as the calcium source and characterized by transmission electron microscopy. Remineralization was either non-existent or restricted to the intrafibrillar mode in ethanol-wet-bonded specimens. Extensive intrafibrillar and interfibrillar remineralization was observed in water-wet-bonded specimens. Water-overwet specimens demonstrated partial remineralization of Hybrid Layers and precipitation of mineralized plates within water channels. The use of ethanol-wet-bonding substantiates that biomimetic remineralization is a progressive dehydration process that replaces residual water in Hybrid Layers with apatite crystallites.
