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Jack L. Ferracane - One of the best experts on this subject based on the ideXlab platform.
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interaction between the oral microbiome and Dental Composite biomaterials where we are and where we should go
Journal of Dental Research, 2020Co-Authors: Jens Kreth, Sharukh S Khajotia, Justin Merritt, Carmem S Pfeifer, Jack L. FerracaneAbstract:Dental Composites are routinely placed as part of tooth restoration procedures. The integrity of the restoration is constantly challenged by the metabolic activities of the oral microbiome. This activity directly contributes to a less-than-desirable half-life for the Dental Composite formulations currently in use. Therefore, many new antimicrobial Dental Composites are being developed to counteract the microbial challenge. To ensure that these materials will resist microbiome-derived degradation, the model systems used for testing antimicrobial activities should be relevant to the in vivo environment. Here, we summarize the key steps in oral microbial colonization that should be considered in clinically relevant model systems. Oral microbial colonization is a clearly defined developmental process that starts with the formation of the acquired salivary pellicle on the tooth surface, a conditioned film that provides the critical attachment sites for the initial colonizers. Further development includes the integration of additional species and the formation of a diverse, polymicrobial mature biofilm. Biofilm development is discussed in the context of Dental Composites, and recent research is highlighted regarding the effect of antimicrobial Composites on the composition of the oral microbiome. Future challenges are addressed, including the potential of antimicrobial resistance development and how this could be counteracted by detailed studies of microbiome composition and gene expression on Dental Composites. Ultimately, progress in this area will require interdisciplinary approaches to effectively mitigate the inevitable challenges that arise as new experimental bioactive Composites are evaluated for potential clinical efficacy. Success in this area could have the added benefit of inspiring other fields in medically relevant materials research, since microbial colonization of medical implants and devices is a ubiquitous problem in the field.
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models of caries formation around Dental Composite restorations
Journal of Dental Research, 2017Co-Authors: Jack L. FerracaneAbstract:The main reason cited for the replacement of Dental Composite restorations is the recurrence of caries. Numerous models—both in vitro, with acid gels or bacterial biofilms, and in situ, with Dental appliances—have been used to study caries formation around Dental Composites. The literature shows that many factors may affect caries formation, including marginal gap formation, gap size, the local chemical environment, the durability of the bonded interface, the extent of bacterial penetration, and the presence of mechanical loading. Studies have also shown that what have been called wall lesions may form independent of surface lesions, though not likely due to microleakage through very small gap spaces in the clinical situation. Gap size and mechanical loading have been shown to be related to lesion severity within in vitro models, but these results do not correspond exactly with those obtained from in situ studies using restorations in Dental appliances. Though not conclusive, some in vitro models have sho...
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a pilot study of a simple photon migration model for predicting depth of cure in Dental Composite
Dental Materials, 2005Co-Authors: Yin Chu Chen, Jack L. Ferracane, Scott A PrahlAbstract:Objectives. The purpose of this study was to build a photo migration model to calculate the radiant exposure (irradiance!time) in Dental Composite and to relate the radiant exposure with extent of cure using polymer kinetics models. Methods. A Composite (Z100, Shade A2) cylinder (21 mm diameter by 15 mm deep) was cured with a tungsten-halogen lamp emitting 600 mW/cm 2 , 1 mm above the Composite for 60 s. For each of the 2!1 mm grids along the longitudinal cross section (diameter versus depth), the degree of conversion (DC) and hardness (KHN) were measured to construct the curing extent distribution. The inverse adding-doubling method was used to characterize the optical properties of the Composite for the Monte Carlo model simulating the photon propagation within the Composite cylinder. The calculated radiant exposure (H) distribution along the cross section was related to the curing extent DC/DCmax distribution and fitted with two polymer curing
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assessing the effect of Composite formulation on polymerization stress
Journal of the American Dental Association, 2000Co-Authors: J.r. Condon, Jack L. FerracaneAbstract:ABSTRACT Background In this study, the authors measured the magnitude of the polymerization stress of a variety of Dental Composite materials and explored the effect of a novel monomer, a methacrylated derivative of styrene-allyl alcohol, or MSAA, in reducing polymerization stress. Methods Eleven commercially available Composites and a series of experimental Composites were evaluated in a mechanical testing machine to measure the maximum stress generated during placement in a confined setting. Results A significant relationship between higher filler volume and increased polymerization stress was found among the commercial materials. Introduction of MSAA produced a 30 percent reduction in polymerization stress in an experimental Composite material. Conclusions Composites that contain lower levels of inorganic filler particles are less likely to produce high levels of polymerization stress during placement. Modifications to traditional Composite chemistry can result in materials that produce lower polymerization stress levels. Clinical Implications The polymerization stress produced by Dental Composite materials during light-curing is a leading reason for bond failures in adhesive restorations, resulting in postoperative sensitivity, marginal staining and recurrent caries.
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Factors effecting Dental Composite wear in vitro.
Journal of biomedical materials research, 1997Co-Authors: J.r. Condon, Jack L. FerracaneAbstract:The wear of posterior Dental Composite restorations takes place through a complex combination of wear mechanisms. To isolate and measure the contribution of the different tribological phenomena in a controlled manner, an oral wear simulator was employed. Results previously reported demonstrated the simulator's ability to form strong correlations with clinical results for both abrasion and attrition wear. These results were generated with the device configured to mimic masticatory dynamics, specifically employing a human enamel stylus, physiologic load levels, and a foodlike slurry for a third body. In this study the slurry was replaced with water to examine the role of the third body in producing abrasion. The third body was found to reduce wear for most materials. In a separate test the enamel stylus tip was replaced with steatite, a semiporous ceramic with wear characteristics similar to enamel when opposing Dental Composite. The use of a steatite antagonist increased abrasion for the larger particle filled materials. The adhesive wear mechanism was found to be a contributing factor in Dental Composite wear.
Reinhard Hickel - One of the best experts on this subject based on the ideXlab platform.
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NAC ameliorates Dental Composite-induced DNA double-strand breaks and chromatin condensation.
Dental materials journal, 2017Co-Authors: Panorea Styllou, Reinhard Hickel, Marianthi Styllou, Christof Högg, Franz X. Reichl, Harry ScherthanAbstract:Released (co)monomers from Dental Composite components can induce DNA damage of which DNA double-strand breaks (DSBs) threaten genome integrity. Here, we tested whether the administration of the antioxidant N-acetylcysteine (NAC) is able to reduce the Dental Composite-induced DSBs in primary human gingiva fibroblasts. The Dental Composites Bis-GMA (bisphenol-Aglycerolate dimethacrylate), GlVIA (glycidyl methacrylate), HEMA (2-hydroxyethyl methacrylate) and TEGDMA (triethyleneglycol dimethacrylate) were found to induce co-localizing microscopic nuclear foci numbers of the DSB markers gamma-H2AX and 53BP1 per cell in the order: GMA>Bis-GMA>TEGDMA>HEMA. Supplementation of (co)monomer-containing culture medium with NAC led to a significant reduction of resin-induced DSBs as well as to an amelioration of Dental monomer-induced nuclear chromatin condensation in gingival fibroblasts. Thus, antioxidant treatment can reduce radical-induced chromatin and DNA damage and open avenues to mitigate genotoxic effects of Dental Composite compounds.
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Dental Composite components induce dna damage and altered nuclear morphology in gingiva fibroblasts
Dental Materials, 2015Co-Authors: Marianthi Styllou, Reinhard Hickel, Panorea Styllou, Christof Högg, Franzxaver Reichl, Ebru Urcan, Lena Rothmund, Harry ScherthanAbstract:Abstract Objective Released Dental Composite components can damage human gingival fibroblasts (HGFs) and their DNA. The cytotoxicity, chromatin condensation and the induction of DNA double strand breaks (DSBs) by different compounds of Dental Composites was investigated using an improved γ-H2AX focus assay. Methods HGFs were incubated with the monomers: bisphenol-A-ethoxylate-dimethacrylate (Bis-DMA), bisphenol-A-glycerolate-dimethacrylate (BisGMA), ethyltriethylen glycol methacrylate (ETEGMA), glycidyl methacrylate (GMA), 1,6-hexandiol-dimethycrylate (HDDMA), trimethylolpropane ethoxylate triacrylate (TMPTA), and acrylamide (ACR). DSBs were determined by enumerating γ-H2AX and 53BP1 foci colocalized at DSBs. Results A concentration-dependent induction of DSBs was found in the order: GMA > BisGMA > ACR > Bis-DMA > HDDMA > TMPTA > ETEGMA. HGFs exposure to GMA (0.3 mM) and to BisGMA (0.09 mM) induced the highest rate of DSB foci, i.e. 12-fold and 8-fold, respectively, relative to control (0.33 DSB foci/cell). At the highest concentrations (EC 50 ) prominent changes in the chromatin morphology of HGF cell nuclei, i.e. compaction of nuclear chromatin and reduction of the area covered by the ovoid fibroblast nuclei, were observed. Nuclear condensation was significantly induced by GMA (1.7-fold at 0.3 mM) and BisGMA (1.6-fold at 0.09 mM), which correlated with the highest numbers of induced DSB foci (GMA, BisGMA, 3.9 and 2.6 foci/cell, respectively). Significance The improved γ-H2AX/53BP1 focus assay revealed a concentration-dependent increase in DSBs for all tested substances. Furthermore, concentration-dependent changes in HGF cell nucleus morphology was noted, demonstrating genotoxic effects of the substances tested.
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Cytotoxicity of Dental Composite (co)monomers and the amalgam component Hg^2+ in human gingival fibroblasts
Archives of Toxicology, 2006Co-Authors: Franzxaver Reichl, Sabine Simon, Magalie Esters, Mario Seiss, Kai Kehe, Norbert Kleinsasser, Reinhard HickelAbstract:Unpolymerized resin (co)monomers or mercury (Hg) can be released from restorative Dental materials (e.g. Composites and amalgam). They can diffuse into the tooth pulp or the gingiva. They can also reach the gingiva and organs by the circulating blood after the uptake from swallowed saliva. The cytotoxicity of Dental Composite components hydroxyethylmethacrylate (HEMA), triethyleneglycoldimethacrylate (TEGDMA), urethanedimethacrylate (UDMA), and bisglycidylmethacrylate (Bis-GMA) as well as the amalgam component Hg^2+ (as HgCl_2) and methyl mercury chloride (MeHgCl) was investigated on human gingival fibroblasts (HGFs) at two time intervals. To test the cytotoxicity of substances, the bromodeoxyuridine (BrdU) assay and the lactate dehydrogenase (LDH) assay were used. The test substances were added in various concentrations and cells were incubated for 24 or 48 h. The EC_50 values were obtained as half-maximum-effect concentrations from fitted curves. Following EC_50 values were found [BrdU: mean (mmol/l); SEM in parentheses; n =12]: (24 h/48 h) HEMA 8.860 (0.440)/6.600(0.630), TEGDMA 1.810(0.130)/1.220(0.130), UDMA 0.120(0.010)/0.140(0.010), BisGMA 0.060(0.004)/0.040(0.002), HgCl_2 0.015(0.001)/0.050(0.006), and MeHgCl 0.004(0.001)/0.005(0.001). Following EC_50 values were found [LDH: mean (mmol/l); SEM in parentheses; n =12]: (24 h/48 h) HEMA 9.490(0.300)/7.890(1.230), TEGDMA 2.300(0.470)/1.950(0.310), UDMA 0.200(0.007)/0.100(0.007), BisGMA 0.070(0.005)/0.100(0.002), and MeHgCl 0.014(0.006)/0.010(0.003). In both assays, the following range of increased toxicity was found for Composite components (24 and 48 h): HEMA
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Silorane-based Dental Composite: Behavior and Abilities
Dental Materials Journal, 2006Co-Authors: Nicoleta Ilie, Reinhard HickelAbstract:The purpose of this study was to examine the characteristics of an innovative Composite material for Dental restorations based on silorane - a monomer with a new chemical composition, and thereby compare the examined characteristics against those of well-known methacrylate-based Composites. Degree of conversion at 2-nim and 6-mm depths as well as hardness, modulus of elasticity, and creep resistance through the middle of 6-mm high samples were measured. It was observed that up to 20 minutes after curing, curing time - and not irradiance - played the determinant role for a high degree of cure. No differences were registered between the two categories of material in terms of hardness. However, modulus of elasticity of the silorane-based material was slightly lower and the creep resistance higher than a methacrylate Composite (Tetric EvoCeram). In conclusion, siloranes exhibited good mechanical properties comparable to those of clinically successful methacrylate-based Composite materials.
Nancy N Maserejian - One of the best experts on this subject based on the ideXlab platform.
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Dental Composite materials and renal function in children
British Dental Journal, 2014Co-Authors: Felicia L Trachtenberg, P. Shrader, Lars Barregard, Nancy N MaserejianAbstract:Investigates concerns that resin-based Composite Dental materials may intra-orally release bisphenol A (BPA), which has been associated with impaired renal function in children and adults. Reports findings that greater exposure to Dental Composite materials was not associated with worse renal function outcomes in children. Objective To examine whether greater exposure to resin-based Composite materials, which may intra-orally release bisphenol A (BPA), is associated with worse renal function outcomes in children. Design Prospective multi-centre study. Setting Community health Dental clinics in Boston and Maine from 1997-2005. Subjects and methods Five hundred and thirty-four New England Children's Amalgam Trial participants aged six to ten years were randomised to treatment with amalgam or resin-based Composite restorations over five years of follow-up. Interventions Restorations were placed according to treatment arm, and sealants placed per standard of care. Cumulative Composite exposure was calculated using surface-years (each treated surface weighted by number years present). Main outcome measures Urinary excretion of albumin, gamma-glutamyl transpeptidase (gamma-GT), and N-acetyl-β-D-glucosaminidase (NAG) were available for 417 children. Results Analysis of covariance showed no association between exposure to Dental Composites, polyacid-modified compomer, or flowable Composite Dental sealants and preventative resin restorations with levels of renal function. There was no association between Composite materials and thresholds indicating renal damage in logistic regression models. Conclusions This study found no harmful associations between Dental Composite materials and renal function in children. Therefore, concerns about renal function need not be a consideration in the choice of Dental restoration material or placement of preventative Dental sealants.
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Dental Composite materials and renal function in children
British Dental Journal, 2014Co-Authors: Felicia L Trachtenberg, P. Shrader, Lars Barregard, Nancy N MaserejianAbstract:Objective To examine whether greater exposure to resin-based Composite materials, which may intra-orally release bisphenol A (BPA), is associated with worse renal function outcomes in children. Design Prospective multi-centre study. Setting Community health Dental clinics in Boston and Maine from 1997-2005. Subjects and methods Five hundred and thirty-four New England Children's Amalgam Trial participants aged six to ten years were randomised to treatment with amalgam or resin-based Composite restorations over five years of follow-up. Interventions Restorations were placed according to treatment arm, and sealants placed per standard of care. Cumulative Composite exposure was calculated using surface-years (each treated surface weighted by number years present). Main outcome measures Urinary excretion of albumin, gamma-glutamyl transpeptidase (gamma-GT), and N-acetyl-β-D-glucosaminidase (NAG) were available for 417 children. Results Analysis of covariance showed no association between exposure to Dental Composites, polyacid-modified compomer, or flowable Composite Dental sealants and preventative resin restorations with levels of renal function. There was no association between Composite materials and thresholds indicating renal damage in logistic regression models. Conclusions This study found no harmful associations between Dental Composite materials and renal function in children. Therefore, concerns about renal function need not be a consideration in the choice of Dental restoration material or placement of preventative Dental sealants.
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Dental Composite Restorations and Psychosocial Function in Children
Pediatrics, 2012Co-Authors: Nancy N Maserejian, P. Shrader, Felicia L Trachtenberg, Russ Hauser, Sonja M. Mckinlay, Mary Tavares, David C. BellingerAbstract:BACKGROUND AND OBJECTIVE: Resin-based Dental materials may intraorally release their chemical components and bisphenol A. The New England Children’s Amalgam Trial found that children randomized to amalgam had better psychosocial outcomes than those assigned to Composites for posterior tooth restorations. The objective of this study was to examine whether greater exposure to Dental Composites is associated with psychosocial problems in children. METHODS: Analysis of treatment-level data from the New England Children’s Amalgam Trial, a 2-group randomized safety trial comparing amalgam with the treatment plan of bisphenol A-glycidyl methacrylate (bisGMA)-based Composite and urethane dimethacrylate–based polyacid-modified Composite (compomer), among 534 children aged 6 to 10 years at baseline. Psychosocial function at follow-up ( n = 434) was measured by using the self-reported Behavior Assessment System for Children (BASC-SR) and parent-reported Child Behavior Checklist (CBCL). RESULTS: Children with higher cumulative exposure to bisGMA-based Composite had poorer follow-up scores on 3 of 4 BASC-SR global scales: Emotional Symptoms (β = 0.8, SE = 0.3, P = .003), Clinical Maladjustment (β = 0.7, SE = 0.3, P = .02), and Personal Adjustment (β = –0.8, SE = 0.2, P = .002). Associations were stronger with posterior-occlusal (chewing) surfaces, where degradation of Composite was more likely. For CBCL change, associations were not statistically significant. At-risk or clinically significant scores were more common among children with greater exposure for CBCL Total Problem Behaviors (16.3% vs 11.2%, P -trend = .01) and numerous BASC-SR syndromes (eg, ≥13 vs 0 surface-years, Interpersonal Relations 13.7% vs 4.8%, P -trend = .01). No associations were found with compomer, nor with amalgam exposure levels among children randomized to amalgam. CONCLUSIONS: Greater exposure to bisGMA-based Dental Composite restorations was associated with impaired psychosocial function in children, whereas no adverse psychosocial outcomes were observed with greater urethane dimethacrylate–based compomer or amalgam treatment levels. * Abbreviations: BASC-SR — : Behavior Assessment for Children–Self-Report bisGMA — : bisphenol A-glycidyl methacrylate BPA — : bisphenol A CBCL — : Child Behavior Checklist NECAT — : New England Children’s Amalgam Trial UDMA — : urethane dimethacrylate
Anne M. Young - One of the best experts on this subject based on the ideXlab platform.
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Chlorhexidine-releasing methacrylate Dental Composite materials
Biomaterials, 2005Co-Authors: Danny Leung, Kishor Gulabivala, Nicola J. Mordan, Jonathan Pratten, Deborah A. Spratt, Anne M. YoungAbstract:Light curable antibacterial, Dental Composite restoration materials, consisting of 80 wt% of a strontium fluoroaluminosilicate glass dispersed in methacrylate monomers have been produced. The monomers contained 40-100 wt% of a 10 wt% chlorhexidine diacetate (CHXA) in hydroxyethylmethacrylate (HEMA) solution and 60-0 wt% of a 50/50 mix of urethane dimethacrylate (UDMA) and triethyleneglycol dimethacrylate (TEGDMA). On raising HEMA content, light cure polymerisation rates decreased. Conversely, water sorption induced swelling and rates of diffusion controlled CHXA release from the set materials increased. Experimental Composites with 50 and 90 wt% of the CHXA in HEMA solution in the monomer were shown, within a constant depth film fermentor (CDFF), to have slower rates of biofilm growth on their surfaces between 1 and 7 days than the commercial Dental Composite Z250 or fluoride-releasing Dental cements, Fuji II LC and Fuji IX. When an excavated bovine dentine cylinder re-filled with Z250 was placed for 10 weeks in the CDFF, both bacteria and polymers from the artificial saliva penetrated between the material and dentine. With the 50 wt% experimental HEMA/CHXA formulation, this bacterial microleakage was substantially reduced. Polymer leakage, however, still occurred. Both polymer and bacterial microleakage were prevented with a 90 wt% HEMA/CHXA restoration in the bovine dentine due to swelling compensation for polymerisation shrinkage in combination with antibacterial release. © 2005 Elsevier Ltd. All rights reserved.
Brigitte Grosgogeat - One of the best experts on this subject based on the ideXlab platform.
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Structural stability of DHMAI antibacterial Dental Composite following in vitro biological aging
Dental Materials, 2020Co-Authors: Fatima Zohra Cherchali, Nina Attik, Mohamed Mouzali, Jean Bernard Tommasino, Hazem Abouelleil, Dominique Decoret, Dominique Seux, Brigitte GrosgogeatAbstract:Objective : To assess the impact of the quaternary ammonium antibacterial agent, Dimethyl-Hexadecyl-Methacryloxyethyl-Ammonium Iodide (DHMAI), on structural stability of an experimental resin Composite after biological aging. Methods : Experimental resin Composites containing 7.5% of DHMAI were incubated in a biological medium in the presence of a Streptococcus Mutans (SM) strain during 3 months. The physicochemical, mechanical, and thermal properties, before and after 3 months of aging, were evaluated using: Degree of Conversion (DC), Residual Functions (RF), Vitreous Transition (Tg), Thermal Expansion Coefficient (CTE) and thermal degradation using Fourier Transform Infrared Spectroscopy Analysis (FTIRATR), Differential Scanning Calorimetry (DSC), Thermo Mechanical analyses (TMA) and Thermo Gravimetric Analysis (TG). Results : Incorporation of DHAMI increased DC and decreased RF. After aging, DHMAI decreased and slowed RF release. Incorporation of 7.5% DHAMI provided significant modification of the thermal behavior (Tg and thermal degradation) but did not affect CTE. After aging, DHMAI enhanced the structural stability and improved resistance against biodegradation compared to the control Composite. Significance : The development of an antibacterial Dental Composite based on DHMAI improved its physical, mechanical, and thermal behaviors, possibly enhancing Dental Composite longevity. Results suggest that DHMAI could be used in the composition of other bioactive Dental materials.
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Effectiveness of the DHMAI monomer in the development of an antibacterial Dental Composite
Dental Materials, 2017Co-Authors: Fatima Zohra Cherchali, Nina Attik, Mohamed Mouzali, Jean Bernard Tommasino, Hazem Abouelleil, Dominique Decoret, Dominique Seux, Brigitte GrosgogeatAbstract:Objective Development of antibacterial Dental Composites is the ultimate goal to decrease carious disease occurrence and increase the restoration longevity. For this purpose, the quaternary ammonium dimethyl-hexadecyl-methacryloxyethyl-ammonium iodide (DHMAI) and the methacryloyloxyethylphosphorylcholine (MPC) have been incorporated in experimental methacrylate-based Composite resins. This aims to first investigate the effect of each alone and then their combined effect. Methods Synthesized DHMAI and commercial MPC were added either alone or combined at different concentrations to experimental Dental Composite. Flexural strength (FS) and modulus (FM) were tested to select the optimal concentrations. Only selected Composites were evaluated for Vickers hardness (HV) and the degree of conversion (DC) using fourier transform infrared spectroscopy analysis (FTIR-ATR). Antibacterial activity was assessed using tests on colony-forming unit (CFU), scanning electron microscopy (SEM) and Alamarblue assay to measure the metabolic activity. Streptococcus mutans biofilm was chosen to be grown on the Composite surfaces during 96 h at 37 °C. Results Incorporation of 7.5% DHMAI in Composite improved the degree of conversion and gave a strong antibacterial effect with a reduction of (∼98%) in CFU and (∼50%) of metabolic activity with acceptable mechanical properties. Addition of MPC to DHMAI affects mechanical properties of Composites without providing a better antibacterial activity. Significance Composites with DHMAI greatly reduced S. mutans biofilm and improved the degree of conversion without scarifying the Composites’ mechanical properties. DHMAI may have wide applicability to other Dental materials in order to inhibit caries and improve the longevity of restorations.
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Confocal time lapse imaging as an efficient method for the cytocompatibility evaluation of Dental Composites.
Journal of Visualized Experiments, 2014Co-Authors: Ghania Nina Attik, Kerstin Gritsch, Pierre Colon, Brigitte GrosgogeatAbstract:It is generally accepted that in vitro cell material interaction is a useful criterion in the evaluation of Dental material biocompatibility. The objective of this study was to use 3D CLSM time lapse confocal imaging to assess the in vitro biocompatibility of Dental Composites. This method provides an accurate and sensitive indication of viable cell rate in contact with Dental Composite extracts. The ELS extra low shrinkage, a Dental Composite used for direct restoration, has been taken as example. In vitro assessment was performed on cultured primary human gingival fibroblast cells using Live/Dead staining. Images were obtained with the FV10i confocal biological inverted system and analyzed with the FV10-ASW 3.1 Software. Image analysis showed a very slight cytotoxicity in the presence of the tested Composite after 5 hours of time lapse. A slight decrease of cell viability was shown in contact with the tested Composite extracts compared to control cells. The findings highlighted the use of 3D CLSM time lapse imaging as a sensitive method to qualitatively and quantitatively evaluate the biocompatibility behavior of Dental Composites.