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Luca Breschi - One of the best experts on this subject based on the ideXlab platform.
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development of an antibacterial and anti metalloproteinase dental Adhesive for long lasting resin composite restorations
Journal of Materials Chemistry B, 2020Co-Authors: Eliseu Aldrighi Münchow, Luca Breschi, Adriana Fernandes Da Silva, Evandro Piva, Carlos Enrique Cuevassuarez, Maria T P Albuquerque, Rodolfo Pinal, Richard L Gregory, Marco C BottinoAbstract:Despite all the advances in Adhesive Dentistry, dental bonds are still fragile due to degradation events that start during application of Adhesive agents and the inherent hydrolysis of resin-dentin bonds. Here, we combined two outstanding processing methods (electrospinning and cryomilling) to obtain bioactive (antimicrobial and anti-metalloproteinase) fiber-based fillers containing a potent matrix metalloproteinase (MMP) inhibitor (doxycycline, DOX). Poly(e)caprolactone solutions containing different DOX amounts (0, 5, 25, and 50 wt%) were processed via electrospinning, resulting in non-toxic submicron fibers with antimicrobial activity against Streptococcus mutans and Lactobacillus. The fibers were embedded in a resin blend, light-cured, and cryomilled for the preparation of fiber-containing fillers, which were investigated with antibacterial and in situ gelatin zymography analyzes. The fillers containing 0, 25, and 50 wt% DOX-releasing fibers were added to aliquots of a two-step, etch-and-rinse dental Adhesive system. Mechanical strength, hardness, degree of conversion (DC), water sorption and solubility, bond strength to dentin, and nanoleakage analyses were performed to characterize the physico-mechanical, biological, and bonding properties of the modified Adhesives. Statistical analyses (ANOVA; Kruskal-Wallis) were used when appropriate to analyze the data (α = 0.05). DOX-releasing fibers were successfully obtained, showing proper morphological architecture, cytocompatibility, drug release ability, slow degradation profile, and antibacterial activity. Reduced metalloproteinases (MMP-2 and MMP-9) activity was observed only for the DOX-containing fillers, which have also demonstrated antibacterial properties against tested bacteria. Adhesive resins modified with DOX-containing fillers demonstrated greater DC and similar mechanical properties as compared to the fiber-free Adhesive (unfilled control). Concerning bonding performance to dentin, the experimental Adhesives showed similar immediate bond strengths to the control. After 12 months of water storage, the fiber-modified Adhesives (except the group consisting of 50 wt% DOX-loaded fillers) demonstrated stable bonds to dentin. Nanoleakage was similar among all groups investigated. DOX-releasing fibers showed promising application in developing novel dentin Adhesives with potential therapeutic properties and MMP inhibition ability; antibacterial activity against relevant oral pathogens, without jeopardizing the physico-mechanical characteristics; and bonding performance of the Adhesive.
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chitosan based extrafibrillar demineralization for dentin bonding
Journal of Dental Research, 2019Co-Authors: X Cai, Luca Breschi, Franklin Chi Meng Tay, J M Guo, D H Pashley, Xiaoyan Wang, Li Na NiuAbstract:Instability of resin-dentin bonds is the Achilles' heel of Adhesive Dentistry. To address this problem, a chelate-and-rinse extrafibrillar dentin demineralization strategy has been developed that keeps intrafibrillar minerals within collagen fibrils intact to prevent activation of endogenous proteases that are responsible for collagen degradation within hybrid layers. The objective of the present study was to evaluate the potential of using chitosan >40 kDa as an antimicrobial extrafibrillar dentin-chelating agent to enhance bond durability. Transmission electron microscopy provided evidence for retention of intrafibrillar minerals and smear plugs in dentin conditioned with 1 wt% chitosan. Analyzed by Kruskal-Wallis analysis of variance, Dunn's statistic, and separate Mann-Whitney tests, tensile bond strengths to wet- and dry-bonded dentin indicated that chelating dentin with chitosan for 60 s prior to bonding did not result in a significant decline in resin-dentin bond strength when compared with that of phosphoric acid etching ( P > 0.05). Gelatinolytic activity within the hybrid layers was examined via in situ zymography after 24-h storage or after thermomechanical cycling and analyzed with 3-factor analysis of variance. After 24 h, enzymatic activity was detected only within completely demineralized phosphoric acid-etched dentin, with values derived from dry bonding significantly higher than those derived from wet bonding ( P < 0.05). Negligible fluorescence was detected within hybrid layers when dentin was conditioned with chitosan, even after thermomechanical cycling, as compared with the controls. Reduction in water permeability in chitosan-conditioned dentin, attributed to smear plug retention, also fostered long-term bond stability. Antibacterial testing performed with live/dead staining indicated that the acetic acid-solubilized chitosan possessed antibacterial activities against 3 single-species biofilms: Streptococcus mutans, Actinomyces naeslundii, and Enterococcus faecalis. Taken together, the new chitosan-based extrafibrillar demineralization strategy retains intrafibrillar minerals, reduces endogenous protease-initiated collagen degradation, prevents water permeation within hybrid layers, and kills bacteria on dentin surfaces, which are crucial factors for enhancing resin-dentin bond durability.
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dentin bonding systems from dentin collagen structure to bond preservation and clinical applications
Dental Materials, 2018Co-Authors: Luca Breschi, Milena Cadenaro, David H Pashley, Leo Tjaderhane, Tatjana Maravic, Sandra Ribeiro Cunha, Allegra Comba, Franklin R Tay, Annalisa MazzoniAbstract:Abstract Objectives Efforts towards achieving durable resin–dentin bonds have been made for decades, including the understanding of the mechanisms underlying hybrid layer (HL) degradation, manufacturing of improved Adhesive systems, as well as developing strategies for the preservation of the HL. Methods This study critically discusses the available peer-reviewed research concerning the formation and preservation of the HL, the mechanisms that lead to the degradation of the HL as well as the strategies to prevent it. Results The degradation of the HL occurs through two main mechanisms: the enzymatic degradation of its collagen fibrils, and the leaching of the resin from the HL. They are enabled by residual unbound water between the denuded collagen fibrils, trapped at the bottom of the HL. Consequently, endogenous dentinal enzymes, such as the matrix metalloproteinases (MMPs) and cysteine cathepsins are activated and can degrade the denuded collagen matrix. Strategies for the preservation of the HL over time have been developed, and they entail the removal of the unbound water from the gaps between the collagen fibrils as well as different modes of silencing endogenous enzymatic activity. Significance Although there are many more hurdles to be crossed in the field of Adhesive Dentistry, impressive progress has been achieved so far, and the vast amount of available research on the topic is an indicator of the importance of this matter and of the great efforts of researchers and dental material companies to reach a new level in the quality and longevity of resin–dentin bonds.
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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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In vivo and in vitro permeability of one-step self-etch Adhesives
Journal of Dental Research, 2004Co-Authors: Stefano Chersoni, Paolo Suppa, Candy Yiu, Luca Breschi, Cecilia Goracci, Francesca Monticelli, Simone Grandini, Carlo Prati, C. Huang, M. FerrariAbstract:Adhesive Dentistry should effectively restore the peripheral seal of dentin after enamel removal. We hypothesize that non-rinsing, simplified, one-step self-etch Adhesives are effective for minimizing dentin permeability after tooth preparation procedures. Crown preparations in vital human teeth were sealed with Adper Prompt, Xeno III, iBond, or One-Up Bond F. Epoxy resin replicas were produced from polyvinyl siloxane impressions for SEM examination. Dentin surfaces from extracted human teeth were bonded with these Adhesives and connected to a fluid-transport model for permeability measurements and TEM examination. Dentinal fluid droplets were observed from Adhesive surfaces in resin replicas of in vivo specimens. In vitro fluid conductance of dentin bonded with one-step self-etch Adhesives was either similar to or greater than that of smear-layer-covered dentin. TEM revealed water trees within the Adhesives that facilitate water movement across the polymerized, highly permeable Adhesives. Both in vitro and in vivo results did not support the proposed hypothesis.
Leo Tjaderhane - One of the best experts on this subject based on the ideXlab platform.
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dentin bonding systems from dentin collagen structure to bond preservation and clinical applications
Dental Materials, 2018Co-Authors: Luca Breschi, Milena Cadenaro, David H Pashley, Leo Tjaderhane, Tatjana Maravic, Sandra Ribeiro Cunha, Allegra Comba, Franklin R Tay, Annalisa MazzoniAbstract:Abstract Objectives Efforts towards achieving durable resin–dentin bonds have been made for decades, including the understanding of the mechanisms underlying hybrid layer (HL) degradation, manufacturing of improved Adhesive systems, as well as developing strategies for the preservation of the HL. Methods This study critically discusses the available peer-reviewed research concerning the formation and preservation of the HL, the mechanisms that lead to the degradation of the HL as well as the strategies to prevent it. Results The degradation of the HL occurs through two main mechanisms: the enzymatic degradation of its collagen fibrils, and the leaching of the resin from the HL. They are enabled by residual unbound water between the denuded collagen fibrils, trapped at the bottom of the HL. Consequently, endogenous dentinal enzymes, such as the matrix metalloproteinases (MMPs) and cysteine cathepsins are activated and can degrade the denuded collagen matrix. Strategies for the preservation of the HL over time have been developed, and they entail the removal of the unbound water from the gaps between the collagen fibrils as well as different modes of silencing endogenous enzymatic activity. Significance Although there are many more hurdles to be crossed in the field of Adhesive Dentistry, impressive progress has been achieved so far, and the vast amount of available research on the topic is an indicator of the importance of this matter and of the great efforts of researchers and dental material companies to reach a new level in the quality and longevity of resin–dentin bonds.
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influence of dimethyl sulfoxide used as a solvent on the physical properties and long term dentin bonding of hydrophilic resins
Journal of The Mechanical Behavior of Biomedical Materials, 2016Co-Authors: Leo Tjaderhane, Thiago Henrique Scarabello Stape, Arzu Tezvergilmutluay, Mustafa Murat Mutluay, Luis Roberto Marcondes Martins, Rosana Leal Do Prado, Eliane Cristina Gava PiziAbstract:Abstract Objective To examine the feasibility of dimethyl sulfoxide (DMSO) incorporation into relatively hydrophilic resins as a new potential method to improve the durability of resin–dentin bonds. Methods Six experimental light-curing BisGMA/HEMA resins solvated in ethanol and DMSO with increasing concentrations of DMSO (0, 0.5, 1, 2, 4 and 10 wt%) were prepared. The degree of conversion (DC) was evaluated by Fourier Transform Infrared Spectroscopy (n=8); water sorption (Wsp) and water solubility (Wso) were gravimetrically assessed (n=10); and flexural strength (FS) and elastic modulus (E) were determined by a three-point bending flexural test (n=10). Flat dentin surfaces on sound third molars (n=10/group) were bonded with resins containing 0, 2, 4 and 10 wt% DMSO used as a two-step etch-and-rinse system. Dentin microtensile bond strength was determined at 24 h and after two-year aging in artificial saliva at 37 °C. Results DMSO significantly affected Wsp (p=0.0006), DC, Wso, FS, and E (p Significance The use of DMSO as a new solvent in Adhesive Dentistry improves dentin bonding of relatively hydrophilic resins over time. 2% DMSO incorporation in BisGMA/HEMA resins should be sufficient to reduce bond strength loss without compromising polymer mechanical strength and physical properties.
Thiago Henrique Scarabello Stape - One of the best experts on this subject based on the ideXlab platform.
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influence of dimethyl sulfoxide used as a solvent on the physical properties and long term dentin bonding of hydrophilic resins
Journal of The Mechanical Behavior of Biomedical Materials, 2016Co-Authors: Leo Tjaderhane, Thiago Henrique Scarabello Stape, Arzu Tezvergilmutluay, Mustafa Murat Mutluay, Luis Roberto Marcondes Martins, Rosana Leal Do Prado, Eliane Cristina Gava PiziAbstract:Abstract Objective To examine the feasibility of dimethyl sulfoxide (DMSO) incorporation into relatively hydrophilic resins as a new potential method to improve the durability of resin–dentin bonds. Methods Six experimental light-curing BisGMA/HEMA resins solvated in ethanol and DMSO with increasing concentrations of DMSO (0, 0.5, 1, 2, 4 and 10 wt%) were prepared. The degree of conversion (DC) was evaluated by Fourier Transform Infrared Spectroscopy (n=8); water sorption (Wsp) and water solubility (Wso) were gravimetrically assessed (n=10); and flexural strength (FS) and elastic modulus (E) were determined by a three-point bending flexural test (n=10). Flat dentin surfaces on sound third molars (n=10/group) were bonded with resins containing 0, 2, 4 and 10 wt% DMSO used as a two-step etch-and-rinse system. Dentin microtensile bond strength was determined at 24 h and after two-year aging in artificial saliva at 37 °C. Results DMSO significantly affected Wsp (p=0.0006), DC, Wso, FS, and E (p Significance The use of DMSO as a new solvent in Adhesive Dentistry improves dentin bonding of relatively hydrophilic resins over time. 2% DMSO incorporation in BisGMA/HEMA resins should be sufficient to reduce bond strength loss without compromising polymer mechanical strength and physical properties.
Milena Cadenaro - One of the best experts on this subject based on the ideXlab platform.
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dentin bonding systems from dentin collagen structure to bond preservation and clinical applications
Dental Materials, 2018Co-Authors: Luca Breschi, Milena Cadenaro, David H Pashley, Leo Tjaderhane, Tatjana Maravic, Sandra Ribeiro Cunha, Allegra Comba, Franklin R Tay, Annalisa MazzoniAbstract:Abstract Objectives Efforts towards achieving durable resin–dentin bonds have been made for decades, including the understanding of the mechanisms underlying hybrid layer (HL) degradation, manufacturing of improved Adhesive systems, as well as developing strategies for the preservation of the HL. Methods This study critically discusses the available peer-reviewed research concerning the formation and preservation of the HL, the mechanisms that lead to the degradation of the HL as well as the strategies to prevent it. Results The degradation of the HL occurs through two main mechanisms: the enzymatic degradation of its collagen fibrils, and the leaching of the resin from the HL. They are enabled by residual unbound water between the denuded collagen fibrils, trapped at the bottom of the HL. Consequently, endogenous dentinal enzymes, such as the matrix metalloproteinases (MMPs) and cysteine cathepsins are activated and can degrade the denuded collagen matrix. Strategies for the preservation of the HL over time have been developed, and they entail the removal of the unbound water from the gaps between the collagen fibrils as well as different modes of silencing endogenous enzymatic activity. Significance Although there are many more hurdles to be crossed in the field of Adhesive Dentistry, impressive progress has been achieved so far, and the vast amount of available research on the topic is an indicator of the importance of this matter and of the great efforts of researchers and dental material companies to reach a new level in the quality and longevity of resin–dentin bonds.
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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.
Marc Hayashi - One of the best experts on this subject based on the ideXlab platform.
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Adhesive Dentistry understanding the science and achieving clinical success
Dental Clinics of North America, 2020Co-Authors: Marc HayashiAbstract:Successful Adhesive Dentistry begins with correct placement and polymerization of the bonding agent. Although numerous agents exist, all abide by certain key principles, including the newest group, the universal Adhesives. Fundamental steps also exist in the application process that require the operator to understand the chemistry of the Adhesive being used. Modalities exist that can help preserve the durability of the bond achieved, thus slowing down the degradation process. However, no material or agent can overcome poor technique. Thus, it is of the utmost importance that the practitioner respects the technique sensitivity of Adhesives, and follows the manufacturer's instructions.
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enhancing dental student learning and skill with dental bonding utilizing a shear bond strength test
Journal of Dental Education, 2018Co-Authors: Marc Hayashi, Kyle Tupaz, Alison Ozaki, Richard G. StevensonAbstract:: Teaching dental students the proper protocol and application of bonding agents for improved composite restorations in the preclinical setting can be challenging due to difficulty in translating their bonding technique to clinical outcomes. The aim of this study was to examine the effectiveness of utilizing a shear bond strength test and to evaluate if it improved student performance and confidence in Adhesive Dentistry. All 106 third-year and 106 fourth-year dental students (total N=212) at the University of California, Los Angeles, School of Dentistry were invited to participate in a shear bond strength workshop in 2016. The hands-on workshop used a bond strength testing instrument to demonstrate the various principles and techniques of Adhesive Dentistry. A total of 54 third-year and 34 fourth-year students (total N=88) participated, for response rates of 51% and 32%, respectively. For the total students, there was a significant difference in the mean bond strength between the first and second attempts (p<0.001). For the third-year students, an increase in the mean shear bond strength was seen but was not significant (p=0.097). For the fourth-year students, there was a significant difference between the first and second attempts (p<0.001). A significant difference was also found in the aggregate self-ratings before and after the exercise (p<0.001). The students rated the exercise as an enjoyable way to learn about Adhesive Dentistry and agreed that it increased their confidence in performing bonding procedures. This exercise served as an innovative method of emphasizing proper technique with Adhesive Dentistry, while helping to build student confidence in the preclinical laboratory.