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1.
Dent Mater ; 34(3): 519-530, 2018 03.
Article in English | MEDLINE | ID: mdl-29373133

ABSTRACT

OBJECTIVES: Camphorquinone (CQ) is the most important photoinitiator used in dental composite resins. Sparse data indicate a mutagenic potential of CQ. Therefore, it was aim of this study to evaluate the cytotoxicity, genotoxicity, and mutagenicity of CQ in L5178Y TK+/- mouse lymphoma cells. METHODS: L5178Y/TK+/- cells were exposed to different concentrations of non-irradiated CQ (0.25-2.5mM). Cytotoxicity was evaluated by propidium iodide assay, determination of suspension growth rate, relative total growth and the mitotic index. Intracellular levels of reactive oxygen/nitrogen species (ROS/RNS) were quantified by 2',7'-dichlorofluoresceine diacetate (DCFH-DA). Early induction of DNA strand breaks and oxidative DNA base lesions was assessed using the 8-hydroxyguanine DNA-glycosylase 1 (hOGG1)-modified alkaline comet assay, whereas mutagenicity of CQ was determined in the mouse lymphoma TK assay (MLA), according to OECD Guideline No. 490. RESULTS: CQ (0.5-2.5mM) induced concentration- and time-dependent inhibition of cell growth associated with increased ROS/RNS production, amounting to 2342%±1108% of controls after 90min at 2.5mM. Additionally, CQ concentration-dependently caused direct DNA-damage, i.e. formation of DNA strand breaks and 8-hydroxy-2'-deoxyguanosine. Whereas the MLA indicated lack of mutagenicity of CQ after a 4h of treatment, CQ concentration-dependently increased total mutant frequency (MF) after 24h (about 2-fold at 2.5mM). But, based on the global evaluation factor concept, increase in MF did not reach biologically relevance. SIGNIFICANCE: CQ induced concentration-dependent, cytotoxic and genotoxic effects in L5178Y/TK+/- cells, most likely due to oxidative stress, but without mediating obvious biological relevant mutagenicity.


Subject(s)
Camphor/analogs & derivatives , Tumor Cells, Cultured/drug effects , Animals , Camphor/toxicity , Cell Survival/drug effects , Comet Assay , DNA Damage/drug effects , In Vitro Techniques , Lymphoma , Mice , Mitotic Index , Mutagenicity Tests , Oxidative Stress , Reactive Oxygen Species/metabolism
2.
Clin Oral Investig ; 18(3): 847-56, 2014 Apr.
Article in English | MEDLINE | ID: mdl-23900792

ABSTRACT

OBJECTIVES: Cells with stem/progenitor properties have been detected in major salivary glands, but no data are available on their presence within minor salivary glands (MSGs). This study aimed to isolate and characterize potential stem/progenitor cells from human MSGs. MATERIALS AND METHODS: MSGs of the lower lip were surgically obtained during biopsy for Sjogren's syndrome investigation that finally proved to be histologically normal. The established MSG cultures were assessed for morphology, proliferation, colony-forming-unit efficiency, multipotentiality, and immunophenotypic characteristics. RESULTS: A mixed population of fibroblast-like and a few flat-shaped epithelial-like cells was obtained. These cells were capable for osteogenic, adipogenic, and neurogenic differentiation. Evidence for strong stem cell potency was observed by the detection of early stem cell markers, like Nanog, Oct-3/4, and SSEA-3. These cells also expressed characteristic mesenchymal stem cell markers, including CD90-Thy1, CD105, CD49f, CD81, nestin, CD146, and Stro-1, but were negative for CD117/C-KIT, CD45, and CD271/NFG. In addition, positivity for keratins 7/8 in part of the population was indicative of an epithelial phenotype, whereas these cells were negative for aquaporin-1 expressed in acinar/myoepithelial cells during development. CONCLUSIONS: Based on these data, a cell population with stem/progenitor characteristics was primarily isolated from labial MSGs. The morphologic and immunophenotypic features indicated that this population is mixed with mesenchymal (mainly) and epithelial characteristics. CLINICAL RELEVANCE: Due to their large number and superficial distribution in labial mucosa, MSGs may be proposed as a potential easily accessible source of adult stem/progenitor cells for regenerative therapies of glandular organs with parenchymal pathology.


Subject(s)
Lip/cytology , Salivary Glands/cytology , Stem Cells/cytology , Female , Humans , Immunophenotyping , Lip/immunology , Middle Aged , Salivary Glands/immunology , Stem Cells/immunology
3.
Arch Oral Biol ; 58(10): 1556-68, 2013 Oct.
Article in English | MEDLINE | ID: mdl-23871383

ABSTRACT

OBJECTIVE: Stem Cells residing in the Apical Papilla (SCAP) of human permanent teeth represent a promising cell source for dental tissue regeneration. Therefore, the functional and molecular properties of specific subpopulations existing within heterogeneous cultures should be further investigated to give insight whether their selection could be beneficial for targeted therapeutic applications. DESIGN: In this study we extensively characterized SCAP cultures established from 10 healthy subjects, as well as their STRO-1(pos/)CD146(pos) and STRO-1(neg/)CD146(pos) subpopulations isolated with fluorescence-activated cell sorting. SCAP were analyzed for embryonic (Nanog, Oct3/4, SSEA-3, TRA-1-60), mesenchymal (STRO-1, CD146/MUC18, CD105/endoglin, CD24, CD90/Thy-1, CD81-TAPA, CD34, CD49f/a6-integrin), neural (CD271/NGFR, nestin) and hematopoietic (CD117/c-kit, CD45) stem cell (SC) markers using flow cytometry. Multipotentiality was evaluated with culture specific staining (Alizarin-Red-S, Oil- Red-O) and RT-PCR analysis for osteo/odontogenic (DSPP, BSP, ALP, osteocalcin, osteonectin, BMP-2, Runx2), adipogenic (lipoprotein-lipase-LPL) and neurogenic (Neurofilament/NFL-L, nestin, ß-tubulin-III, NCAM) markers. RESULTS: Our results showed that the STRO-1(pos)/CD146(pos) subpopulation demonstrated higher CFU efficiency and much higher expression of several embryonic and mesenchymal SC markers compared to the non-sorted SCAP. They also showed enhanced odontogenic differentiation potential, as evidenced by higher mineralization capacity and expression of osteo/odontogenic markers. By contrast, absence of STRO-1 in the STRO-1(neg)/CD146(pos) subpopulation yielded the opposite results and was associated with significant downgrading of the above-mentioned properties. CONCLUSIONS: These results suggest that STRO-1(pos)/CD146(pos) SCAP cells represent a very promising adult MSCs source with enhanced multipotent SC properties that could be easily isolated with simple flow cytometric methods to be used for tissue engineering applications.


Subject(s)
Antigens, Surface/analysis , CD146 Antigen/analysis , Dental Papilla/cytology , Multipotent Stem Cells/physiology , Biomarkers/analysis , Cell Differentiation/physiology , Cell Proliferation , Cells, Cultured , Culture Media , Flow Cytometry , Humans , Odontogenesis/physiology , Osteogenesis/physiology , Reverse Transcriptase Polymerase Chain Reaction , Staining and Labeling
4.
Arch Oral Biol ; 56(7): 709-21, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21227403

ABSTRACT

OBJECTIVE: The aim of this study was to compare the in vitro osteo/odontogenic differentiation potential of mesenchymal stem cells (MSCs) derived from the dental pulp (dental pulp stem cells - DPSCs) or the apical papilla (stem cells from the apical papilla - SCAP) of permanent developing teeth. DESIGN: DPSCs and SCAP cultures were established from impacted third molars of young healthy donors at the stage of root development. Cultures were analysed for stem cell markers, including STRO-1, CD146, CD34 and CD45 using flow cytometry. Cells were then induced for osteo/odontogenic differentiation by media containing dexamethasone, KH(2)PO(4) and ß-glycerophosphate. Cultures were analysed for morphology, growth characteristics, mineralization potential (Alizarin Red method) and differentiation markers (dentine sialophosphoprotein-DSPP, bone sialoprotein-BSP, osteocalcin-OCN, alkaline phosphatase-ALP), using immunocytochemistry and reverse transcriptase-polymerase chain reaction. RESULTS: All DPSCs and SCAP cultures were positive for STRO-1, CD146 and CD34, in percentages varying according to cell type and donor, but negative for CD45. Both types of MSCs displayed an active potential for cellular migration, organization and mineralization, producing 3D mineralized structures. These structures progressively expressed differentiation markers, including DSPP, BSP, OCN, ALP, having the characteristics of osteodentin. SCAP, however, showed a significantly higher proliferation rate and mineralization potential, which might be of significance for their use in bone/dental tissue engineering. CONCLUSIONS: This study provides evidence that different types of dental MSCs can be used in tissue engineering/regeneration protocols as an approachable stem cell source for osteo/odontogenic differentiation and biomineralization that could be further applied for stem cell-based clinical therapies.


Subject(s)
Dental Pulp/cytology , Gingiva/cytology , Mesenchymal Stem Cells/physiology , Odontogenesis/physiology , Osteogenesis/physiology , Adolescent , Alkaline Phosphatase/analysis , Antigens, CD34/analysis , Antigens, Surface/analysis , Buffers , CD146 Antigen/analysis , Calcification, Physiologic/physiology , Cell Culture Techniques , Cell Differentiation/physiology , Cell Movement/physiology , Cell Proliferation , Cells, Cultured , Dexamethasone/pharmacology , Extracellular Matrix Proteins/analysis , Glucocorticoids/pharmacology , Glycerophosphates/pharmacology , Humans , Integrin-Binding Sialoprotein/analysis , Leukocyte Common Antigens/analysis , Osteocalcin/analysis , Phosphates/pharmacology , Phosphoproteins/analysis , Potassium Compounds/pharmacology , Sialoglycoproteins/analysis , Time Factors
5.
Dent Mater ; 22(6): 499-505, 2006 Jun.
Article in English | MEDLINE | ID: mdl-16198408

ABSTRACT

OBJECTIVES: Oral and systemic cells are permanently exposed to various types of xenobiotics, such as dental restorative materials, which may subsequently cause adverse effects. Objective of the present investigation was to analyze the effects of three important resin monomers on the glutathione metabolism of human gingival fibroblasts after an incubation period of 4h. METHODS: Cells were exposed to various concentrations of 2-hydroxyethyl methacrylate (HEMA; 0.1-10 mM), triethylene-glycol dimethacrylate (TEGDMA; 0.05-2.5 mM), and urethane dimethacrylate (UDMA; 0.005-0.25 mM). Subsequently, cellular glutathione (GSH) concentrations were determined after a treatment period of 4h using the monobromobimane assay. Data were statistically evaluated using Tukey ANOVA with p<0.05. RESULTS: GSH depletion was dependent on the type of the resin monomer: UDMA>TEGDMA>HEMA. The concentrations for a 50%-reduction of cellular GSH varied between 0.1 mM (0.05 mM) (UDMA), 0.33 mM (0.09 mM) (TEGDMA), and 1.6 mM (0.8 mM) (HEMA). Simultaneously, no decrease of cell numbers was found at any tested concentration. SIGNIFICANCE: These data indicate that the investigated resins may cause cell damage due to depletion of intracellular GSH level even at low concentrations within a short period of time. The decrease of GSH is an early reaction, which is triggered prior to other cytotoxic alterations.


Subject(s)
Composite Resins/pharmacology , Dental Materials/pharmacology , Fibroblasts/drug effects , Gingiva/drug effects , Glutathione/drug effects , Methacrylates/pharmacology , Polyethylene Glycols/pharmacology , Polymethacrylic Acids/pharmacology , Polyurethanes/pharmacology , Resin Cements/pharmacology , Bridged Bicyclo Compounds , Cell Count , Cells, Cultured , Dose-Response Relationship, Drug , Fibroblasts/metabolism , Fluorescent Dyes , Gingiva/metabolism , Glutathione/analysis , Humans , Materials Testing , Sulfhydryl Reagents
6.
J Biomed Mater Res B Appl Biomater ; 75(2): 272-6, 2005 Nov.
Article in English | MEDLINE | ID: mdl-16080163

ABSTRACT

Glutathione (GSH) is important for the self-protection of cells against oxidative stress and toxic xenobiotics, whereas reactive oxygen species (ROS) at elevated concentrations may cause detrimental alterations of cell membranes, DNA, and other cellular structures. The present investigation addressed the effects of triethylene-glycoldimethacrylate (TEGDMA) and camphorquinone (CQ) on glutathione metabolism and the formation of ROS in oral cells. Primary human pulp fibroblasts were exposed to various concentrations of TEGDMA and CQ (0.1-5 mM). Subsequently, GSH concentration and ROS formation were analyzed with the use of the monobromobimane assay (GSH) and 2',7'-dichlorofluorescein diacetate (DCFH-DA) (ROS). The endogenous ROS hydrogen peroxide (H2O2) was used as a positive control (0.02-2 mM). TEGDMA significantly decreased GSH at concentrations between 0.5 and 5 mM (p<0.05), but did not elevate ROS levels. Contrary, CQ increased ROS formation at concentrations>or=1 mM, but had only a moderate effect on GSH at the highest test concentration. Hydrogen peroxide increased ROS and simultaneously decreased GSH at concentrations of >or=0.2 mM. These data show that the investigated substances may cause cell damage due to various mechanisms, GSH decrease and/or ROS increase. As a consequence, TEGDMA and CQ released into an aqueous environment from resinous materials might interact, thus generating significant cytotoxic effects even at low concentrations.


Subject(s)
Dental Pulp/cytology , Dental Pulp/drug effects , Fibroblasts/drug effects , Fibroblasts/metabolism , Glutathione/metabolism , Polyethylene Glycols/pharmacology , Polymethacrylic Acids/pharmacology , Reactive Oxygen Species/metabolism , Terpenes/pharmacology , Cells, Cultured , Humans
7.
J Dent Res ; 82(10): 814-8, 2003 Oct.
Article in English | MEDLINE | ID: mdl-14514762

ABSTRACT

Previous in vivo studies have revealed that resins may generate a persistent inflammation of oral tissues and cell death as well. Apoptosis is an important regulated process that results in rapid cell death. This study tested the hypothesis that the comonomer triethyleneglycol-dimethacrylate (TEGDMA) causes apoptosis. The effects of TEGDMA on proliferation and apoptosis in primary oral fibroblasts were analyzed by light microscopy and flow cytometry (FACS; Annexin V-assay). TEGDMA at 5 and 7.5 mM inhibited proliferation after 24 hrs. No increased frequency of apoptosis or necrosis was observed with 1 mM or 2.5 mM TEGDMA after 24 hrs. Apoptosis and Annexin V-positive cells were observed with 5 mM and 7.5 mM TEGDMA by light microscopy after 24 hrs. A dramatic increase in apoptotic cells was detected by FACS after 24 hrs with 7.5 mM TEGDMA. Thus, TEGDMA was cytotoxic and "apoptotic" in a dose- and time-dependent manner.


Subject(s)
Apoptosis/drug effects , Composite Resins/toxicity , Dental Materials/toxicity , Fibroblasts/drug effects , Gingiva/drug effects , Polyethylene Glycols/toxicity , Polymethacrylic Acids/toxicity , Analysis of Variance , Annexin A5 , Cell Culture Techniques , Cell Division/drug effects , Enzyme Inhibitors , Flow Cytometry , Gingiva/cytology , Humans , Necrosis , Time Factors
8.
Clin Oral Investig ; 7(4): 212-6, 2003 Dec.
Article in English | MEDLINE | ID: mdl-12938021

ABSTRACT

The aim of this study was to investigate the in vitro effects of low concentrations of chlorhexidine (CHX) on the proliferation of Streptococcus sobrinus (ATCC 33478) and primary human gingival fibroblasts (HGF). Liquid cultures of bacteria or human gingival fibroblasts were exposed to CHX concentrations ranging from 0.07 to 40 microM in microtiter plates at 37 degrees C for 24 h. Bacteria or cells grown without CHX served as controls. The effects of CHX were determined either by measurements of the optical density (OD) of bacterial cultures or by evaluation of cell growth with the DNA-intercalating fluorescent stain H33342 in comparison to untreated controls. Results were evaluated calculating means and standard deviations. Data were statistically analyzed by an ANOVA using Post Hoc tests ( p<0.005). No growth inhibition of S. sobrinus was found at concentrations between 0.07 and 0.15 microM CHX, whereas 0.3 microM CHX led to an elongated (2 h more) lag phase and 0.6 microM CHX induced a lag phase of 4 h more and a minor inclination of the curve in the log phase. Concentrations of CHX>/=1.25 microM completely inhibited growth of S. sobrinus. On the contrary, CHX showed no significant effect on growth of HGF at concentrations

Subject(s)
Anti-Infective Agents, Local/administration & dosage , Anti-Infective Agents, Local/toxicity , Chlorhexidine/administration & dosage , Chlorhexidine/toxicity , Gingiva/drug effects , Streptococcus sobrinus/drug effects , Analysis of Variance , Cell Division/drug effects , Cells, Cultured , Fibroblasts/drug effects , Gingiva/cytology , Humans
9.
J Endod ; 28(11): 749-53, 2002 Nov.
Article in English | MEDLINE | ID: mdl-12470017

ABSTRACT

It was the purpose of our study to determine the cytotoxicity of several types of root canal sealers in vitro over the period of 1 yr by using a new test model. Roots of extracted human teeth were filled with N2, Apexit, Roekoseal, AH Plus, Ketac Endo, Endomethasone, and one gutta-percha point. In addition, roots filled with laterally condensed gutta-percha/N2. Teeth filled with one gutta-percha point only were controls. All specimens were consecutively extracted with distilled water for a total period of 1 yr. Extracts were investigated for cytotoxicity by using immortalized 3T3 fibroblasts and primary human periodontal ligament fibroblasts. Results were statistically analyzed with Dunnett's t tests (p < 0.05). Pronounced cytotoxic effects were only caused by N2-extracts in both cell cultures (p < 0.05). Furthermore, statistically significant cytotoxic alterations were also induced by 10-week eluates of Endomethasone (p < 0.05). All other investigated materials did not significantly alter cell metabolism.


Subject(s)
Administration, Topical , Biocompatible Materials/toxicity , Hydrocortisone , Root Canal Filling Materials/toxicity , Thymol/analogs & derivatives , 3T3 Cells , Animals , Anti-Inflammatory Agents/toxicity , Biocompatible Materials/chemistry , Calcium Hydroxide/toxicity , Cell Culture Techniques , Dental Cements/toxicity , Dexamethasone/toxicity , Drug Combinations , Epoxy Resins/toxicity , Eugenol/toxicity , Fibroblasts/drug effects , Formaldehyde/toxicity , Glass Ionomer Cements/toxicity , Gutta-Percha/toxicity , Humans , Hydrogen-Ion Concentration , Mice , Periodontal Ligament/cytology , Periodontal Ligament/drug effects , Root Canal Filling Materials/chemistry , Statistics as Topic , Thymol/toxicity , Time Factors , Zinc Oxide/toxicity
10.
J Endod ; 28(11): 784-6, 2002 Nov.
Article in English | MEDLINE | ID: mdl-12470025

ABSTRACT

The purpose of this study was to evaluate the cellular compatibility of five endodontic sealers in the first 24 h after mixing. Specimens of N2, Endomethasone, Apexit, AH Plus, and Ketac Endo were extracted with cell culture medium 0, 1, 5, and 24 h after mixing. Eluates were tested for cytotoxicity with immortal 3T3 cells and primary human periodontal ligament fibroblasts using XTT-assays. Data were analyzed for statistically significant differences by means of Dunnett's t tests (p < 0.05). All extracts of N2 completely inhibited cell metabolism (p < 0.05). Similar effects were provoked by the first three eluates of Endomethasone, but the 24-h extract irritated cells significantly less (p < 0.05). Severe cytotoxicity was also observed with all Ketac Endo extracts (p < 0.05). A significant inhibition of mitochondrial activity was induced by the first (3T3) or the first and second eluate (periodontal ligament fibroblasts) of AH Plus (p < 0.05). The subsequent eluates of this sealer and all extracts of Apexit did not reveal any cytotoxic potency.


Subject(s)
Administration, Topical , Biocompatible Materials/toxicity , Hydrocortisone , Root Canal Filling Materials/toxicity , Thymol/analogs & derivatives , 3T3 Cells , Animals , Anti-Inflammatory Agents/toxicity , Biocompatible Materials/chemistry , Calcium Hydroxide/toxicity , Dexamethasone/toxicity , Drug Combinations , Epoxy Resins/toxicity , Eugenol/toxicity , Fibroblasts/drug effects , Formaldehyde/toxicity , Glass Ionomer Cements/toxicity , Humans , Indicators and Reagents , Irritants/toxicity , Mice , Periodontal Ligament/cytology , Periodontal Ligament/drug effects , Root Canal Filling Materials/chemistry , Statistics as Topic , Tetrazolium Salts , Thymol/toxicity , Time Factors , Zinc Oxide/toxicity
11.
J Biomed Mater Res ; 63(6): 746-51, 2002.
Article in English | MEDLINE | ID: mdl-12418019

ABSTRACT

Previous studies revealed that primarily small and relatively hydrophilic comonomers, such as TEGDMA, leach out of resin-based restorative materials into aqueous media. Subsequently, these compounds may cause detrimental reactions with intracellular metabolic systems. The present experiments attempted to elucidate the interactions of TEGDMA with the important intracellular reducing agent glutathione (GSH). The influence of various concentrations of TEGDMA (0.5-7.5 mM) on viability and intracellular GSH concentration of primary human gingival fibroblasts was determined by means of a fluorescence assay (monobromobimane) performed in microtiter plates. Cells were treated with TEDGMA between 2 and 24 h. The incubation of fibroblasts with TEGDMA even at subtoxic concentrations quickly decreased the intracellular glutathione level to 30-50% of controls within the first 2-6 hours. However, no simultaneous adverse effect on cell viability was found. Longer incubation periods up to 24 h caused a regulatory reincrease at TEGDMA concentrations

Subject(s)
Composite Resins/toxicity , Gingiva/drug effects , Gingiva/metabolism , Glutathione/metabolism , Polyethylene Glycols/toxicity , Polymethacrylic Acids/toxicity , Cell Survival/drug effects , Cells, Cultured , Fibroblasts/cytology , Fibroblasts/drug effects , Fibroblasts/metabolism , Fluorescent Dyes , Gingiva/cytology , Humans , Materials Testing , Oxidation-Reduction
12.
Clin Oral Investig ; 6(2): 92-7, 2002 Jun.
Article in English | MEDLINE | ID: mdl-12166720

ABSTRACT

Fluoride is used in dentistry as a prophylactic agent to reduce caries rates due to the demineralization/remineralization effect and its influence on the metabolism of cariogenic bacteria. The purpose of this study was to evaluate the cytotoxic effects of sodium fluoride (NaF) on three different cell lines and the antibacterial potency on Streptococcus sobrinus. Cell lines were treated with various concentrations of NaF ranging from 0.039 mM to 10 mM for 24 h. For microbial assays, concentrations of NaF between 0.03 mM and 10 mM were added to liquid cultures of bacteria. Our results showed that immortalized human keratinocytes (HaCaT) and human osteogenic sarcoma cells (SAOS-2) were similarly affected by concentrations up to 2.5 mM. However, cell growth of HaCaT was slightly more inhibited at 2.5 mM of NaF than SAOS-2. At concentrations between 0.62 mM and 10 mM, 3T3 mouse fibroblast cells reacted more sensitively than HaCaT and SAOS-2 to NaF. The 3T3 cells did not survive in the presence of 10 mM NaF. NaF caused no significant effect on all tested cells at concentrations of < or = 0.31 mM. NaF at 0.039 mM and 0.06 mM did not affect growth of S. sobrinus. At concentrations of 0.125 mM and 0.5 mM, growth was slightly reduced. The proliferation of S. sobrinus significantly decreased at 1 mM and 2 mM NaF. S. sobrinus survived at 4 mM, revealing a delayed log phase with a decreased proliferation. No viable S. sobrinus cells were detected at concentrations of > or = 8 mM NaF. Data analysis revealed that overall treatment effects were highly significant (P<0.05, analysis of variance, Tukey's difference test). This study indicates that cytotoxic effects due to NaF significantly vary in dependence upon the applied cell line. The toxicity of NaF approached 50% (TC50) at concentrations of 6 mM for HaCaT, 2.3 mM for 3T3 cells, and 7.5 mM for SAOS-2. Additionally, NaF revealed antimicrobial effects only at concentrations that are significantly higher than oral fluoride concentrations.


Subject(s)
Cariostatic Agents/toxicity , Sodium Fluoride/toxicity , Streptococcus sobrinus/drug effects , 3T3 Cells/drug effects , Analysis of Variance , Animals , Cariostatic Agents/administration & dosage , Cell Division/drug effects , Cell Line , Cell Survival , Colony Count, Microbial , Dental Caries/microbiology , Dose-Response Relationship, Drug , Humans , Keratinocytes/drug effects , Mice , Osteosarcoma/pathology , Osteosarcoma/physiopathology , Sodium Fluoride/administration & dosage , Statistics as Topic , Tumor Cells, Cultured
13.
J Dent Res ; 80(8): 1777-80, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11669493

ABSTRACT

Previous experiments have shown that mechanical stress may alter the interactions between cells and extracellular matrix (ECM). The purpose of our study was to investigate the effects of mechanical load on metabolism and ECM expression of primary human periodontal cells. The influence of gravitational force on proliferation, lactate dehydrogenase (LDH) release, and tenascin expression of gingival (HGF) and periodontal ligament fibroblasts (HPDL), as well as their adhesion to various extracellular matrix (ECM) components, was determined. Cells were centrifuged in microplates or flat tubes for 16 hrs at 217 g. Neither an enhanced release of LDH nor an alteration of cell proliferation could be detected after centrifugation. However, the attachment of loaded gingival and periodontal ligament fibroblasts to all tested ECM components significantly decreased in comparison with controls (Wilcoxon-Mann-Whitney test; HGF, p < 0.05; HPDL, p < 0.01). Tenascin expression of mechanically stressed fibroblasts significantly increased in comparison with controls (p < 0.01).


Subject(s)
Fibroblasts/physiology , Gingiva/physiology , Periodontal Ligament/physiology , Cell Adhesion/physiology , Cell Communication/physiology , Cell Division/physiology , Cells, Cultured , Extracellular Matrix/metabolism , Extracellular Matrix/physiology , Fibroblasts/metabolism , Gingiva/cytology , Gingiva/metabolism , Gravitation , Humans , L-Lactate Dehydrogenase/metabolism , Periodontal Ligament/cytology , Periodontal Ligament/metabolism , Statistics, Nonparametric , Stress, Mechanical , Tenascin/metabolism
14.
J Dent Res ; 80(3): 869-75, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11379887

ABSTRACT

Earlier studies have shown that the comonomer triethyleneglycol-dimethacrylate (TEGDMA) and the photostabilizer 2-hydroxy-4-methoxybenzophenone (HMBP) are cytotoxic and inhibit cell growth. It was the aim of this study to elucidate the underlying metabolic effects of TEGDMA and HMBP on immortal contact-inhibited Swiss albino mouse embryo cells (3T3 fibroblasts) by nuclear magnetic resonance (NMR) spectroscopy. Cell extracts and culture media were analyzed by NMR spectroscopy for metabolic changes after incubation for 24 hours with ED20-concentrations of TEGDMA and HMBP. TEGDMA could be detected in all fractions (cytosol, lipid fractions, and culture media) of 3T3 cells, while HMBP was found only in the lipid fraction accumulated at a maximum rate (51 nmol/mg DNA) compared with TEGDMA (27 nmol/mg DNA). TEGDMA increased the concentration of phosphomonoesters to 180+/-36% and decreased the phosphodiesters to 65+/-5% of controls (control = 100%). Thus, the turnover of phospholipids was enhanced, whereas content and composition of phospholipids of membranes did not alter markedly. Additionally, TEGDMA changed the metabolic state of cells, indicated by slight decreases of nucleoside triphosphates and an increase in the ratio of nucleoside diphosphates to nucleoside triphosphates, while HMBP had no effect. The most remarkable effect of TEGDMA was a nearly complete decline of the intracellular glutathione levels. Analysis of our data shows that NMR spectroscopy of cell-material interactions may reveal metabolic effects of organic test substances which are not detectable by standard in vitro assays. The comonomer TEGDMA affected the metabolism of the cells on different levels, while HMBP accumulated in the lipid fraction and induced significantly fewer effects on cell metabolism.


Subject(s)
3T3 Cells/drug effects , Composite Resins/toxicity , 3T3 Cells/chemistry , 3T3 Cells/metabolism , Animals , Benzophenones/toxicity , Cell Division/drug effects , Culture Media , Cytosol/chemistry , Cytosol/drug effects , DNA/analysis , Glutathione/analysis , Glycerylphosphorylcholine/analysis , Lipids/analysis , Magnetic Resonance Spectroscopy , Membrane Lipids/analysis , Mice , Nucleotides/analysis , Phosphocreatine/analysis , Phospholipids/analysis , Phosphorylcholine/analysis , Polyethylene Glycols/toxicity , Polymethacrylic Acids/toxicity
15.
J Dent Res ; 80(12): 2046-50, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11808759

ABSTRACT

Most dental resinous materials contain high quantities of the diluent monomer triethyleneglycol-dimethacrylate (TEGDMA). Due to its 'hydrophilic' nature, significant amounts of this substance leach into an aqueous environment, such as the oral cavity. Therefore, it is hypothesized that TEGDMA frequently interferes with oral and/or systemic tissues. In vitro studies revealed that TEGDMA is considerably cytotoxic in various cell cultures. It has also been observed that TEGDMA can easily penetrate membranes and subsequently may react with intracellular molecules. The formation of glutathione-TEGDMA adducts is of specific interest, since the nearly complete exhaustion of this molecule significantly reduces its cellular detoxifying potency. Large deletions of DNA sequences were caused by TEGDMA, resulting in high mutation frequency. In addition, TEGDMA has been identified as an important resinous sensitizer in patients and professionals. Taken together, available in vitro information, in vivo studies with animals, and clinical data as well indicate that TEGDMA may contribute considerably to local and systemic adverse effects caused by dental resins.


Subject(s)
Composite Resins/toxicity , Mutagens , Polyethylene Glycols/toxicity , Polymethacrylic Acids/toxicity , Animals , Cell Membrane/drug effects , Cells, Cultured/drug effects , Composite Resins/metabolism , DNA Damage , Glutathione/metabolism , Humans , Membrane Lipids/metabolism , Mutagens/metabolism , Polyethylene Glycols/metabolism , Polymethacrylic Acids/metabolism
16.
J Biomed Mater Res ; 53(6): 632-9, 2000.
Article in English | MEDLINE | ID: mdl-11074420

ABSTRACT

Previous studies have documented a marked cytotoxic potency of BisGMA and TEGDMA. The purpose of this investigation was to determine if these substances also affect proliferation, migration, and tenascin expression of primary human gingival fibroblasts (HGF) and immortalized human keratinocytes (HaCaT). These parameters play an important role in healing wounds. HGF and HaCaT cultures were incubated with TEGDMA and BisGMA. Cell proliferation (BrdU-assay) and migration (Boyden method) were determined 24 h after incubation. Tenascin expression was investigated four and seven days after treatment. Results were statistically evaluated by ANOVA using the Wilcoxon-Mann-Whitney test (p < 0.05). Proliferation of both cell types was significantly inhibited at concentrations > or = 0.25 mM (TEGDMA) or > or = 0.01 mM (BisGMA). Migration of HaCaT was significantly increased after incubation with BisGMA for 24 h. TEGDMA did not alter migration of HGF and HaCaT. In addition, TEGDMA had no effect on tenascin expression of both cell cultures. After 4 days of incubation, BisGMA (at a concentration of 0.01 mM) significantly reduced tenascin production of HaCaT cultures related to cell number. However, 7 days after treatment, BisGMA significantly increased tenascin expression of HGF and HaCaT cultures. Altogether, our results indicate that BisGMA can affect migration of keratinocytes and alters the expression of the extracellular matrix component tenascin. Thus, BisGMA may significantly influence the healing of injured oral tissues.


Subject(s)
Bisphenol A-Glycidyl Methacrylate/pharmacology , Keratinocytes/drug effects , Polyethylene Glycols/pharmacology , Polymethacrylic Acids/pharmacology , Tenascin/biosynthesis , Antimetabolites , Bromodeoxyuridine , Cell Division/drug effects , Cell Movement/drug effects , Cells, Cultured , Fibroblasts/metabolism , Humans , Keratinocytes/metabolism , Wound Healing/drug effects
17.
Clin Oral Investig ; 4(4): 219-25, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11218492

ABSTRACT

The purpose of this study was (a) to evaluate the cytocompatibility of three resorbable and nonresorbable membranes in fibroblast and osteoblast-like cell cultures and (b) to observe the growth of those cells on the various barriers by scanning electron microscopy (SEM). Primary human periodontal ligament fibroblasts (HPLF) and human osteoblast-like cells (SAOS-2) were incubated with nonresorbable polytetrafluoroethylene (ePTFE) barriers and resorbable polylactic acid as well as collagen membranes. Cytotoxic effects were determined by XTT (mitochondrial metabolic activity) and sulforhodamine B assays (cellular protein content). In addition, HPLF and SAOS-2 grown for 21 days on the investigated barriers were evaluated by SEM. Data were analyzed statistically by ANOVA using the Wilcoxon-Mann-Whitney test (P < 0.05). No changes were established in the periodontal ligament fibroblasts and human osteoblast-like cells after incubation with the collagen membrane. Cytotoxic effects, however, were induced by the polylactic acid barrier which slightly inhibited cell metabolism of the periodontal fibroblasts (XTT: 90.1% +/- 3.6 of control value). Moderate cytotoxic reactions were caused by the nonresorbable ePTFE membrane in HPLF-cultures (XTT: 82.7% +/- 3.5) and osteoblast-like cell monolayers (XTT: 80.0% +/- 0.6%). Mitochondrial activity in both cell cultures was significantly reduced by ePTFE barriers in comparison to non-incubated control cells (P = 0.028). SEM analysis of cell behavior on barriers demonstrated the differences between these materials: collagen barriers were densely populated with HPLF and SAOS-2, whereas only few or no cells were seen to adhere to the ePTFE and polylactic acid membranes. Our findings indicate that the collagen barrier investigated is very cytocompatible and may be integrated into connective tissue well. On the contrary, the ePTFE and polylactic acid membranes induced slight to moderate cytotoxic reactions which may reduce cellular adhesion. Thus, gap formation between the barrier surface and the connective tissue may be promoted which may facilitate epithelial downgrowth and microbial accumulation. Consequently, these effects may reduce the potential gain in periodontal attachment.


Subject(s)
Biocompatible Materials/toxicity , Citrates/toxicity , Collagen/toxicity , Membranes, Artificial , Polyesters/toxicity , Polytetrafluoroethylene/toxicity , Absorbable Implants/adverse effects , Analysis of Variance , Biotransformation , Fibroblasts/drug effects , Guided Tissue Regeneration, Periodontal , Humans , Materials Testing , Microscopy, Electron, Scanning , Mitochondria/enzymology , Osteoblasts/drug effects , Periodontal Ligament/cytology , Periodontal Ligament/drug effects , Statistics, Nonparametric , Toxicity Tests
18.
J Biomed Mater Res ; 48(6): 772-7, 1999.
Article in English | MEDLINE | ID: mdl-10556839

ABSTRACT

It was the aim of our study to investigate the composition and cytotoxicity of aqueous elutes from five dentin adhesives currently used in clinical practice: Solobond Plustrade mark, Solisttrade mark, Scotchbond Multipurposetrade mark, Syntac SCtrade mark, and Prime & Bondtrade mark 2.1. Water extracts were analyzed by gas chromatography/mass spectrometry (GC/MS) and relative quantities of identified compounds were compared by means of an internal caffeine standard [%CF]. The in vitro cytotoxic effects of substances released into DMEM were determined using immortalized 3T3-fibroblast cultures. In addition, the cytotoxicity of ethylene glycol (EG), which was identified in the extracts of Syntac SC, was evaluated. All dentin adhesives tested released various chemical components, like comonomers (mainly ethylene glycol compounds), HEMA, and initiating substances (e.g., camphorquinone). Elutes of Solobond Plus, which contained very high amounts of TEGDMA, were extremely cytotoxic. Two bonding agents (Scotchbond Multi-purpose, Syntac SC), which released significant quantities of HEMA, induced severe cytotoxic effects. In contrast, extracts from Solist and Prime & Bond 2.1 had very small effects on cell proliferation; these elutes contained small amounts of released chemical compounds. EG, a product of HEMA hydrolysis, in concentrations ranging from 0.025-25 mM was not cytotoxic. In summary, these results provide evidence that all dentin adhesives tested in the present study release in aqueous media chemical compounds some of which (for example, TEGDMA and HEMA) are cytotoxic.


Subject(s)
Dentin-Bonding Agents/toxicity , 3T3 Cells , Animals , Cell Survival/drug effects , Dentin-Bonding Agents/chemistry , Gas Chromatography-Mass Spectrometry , Mice , Water
19.
Dent Mater ; 15(3): 196-201, 1999 May.
Article in English | MEDLINE | ID: mdl-10551084

ABSTRACT

OBJECTIVES: The aims of this investigation were to measure the surface microhardness (Vickers) as well as the release of fluoride from four polyacid-modified composite resins (PMC) ("compomers") (Compoglass F, F 2000, Dyract AP, experimental compomer) after storage in various artificial saliva (buffers) including one esterase-buffer. METHODS: Samples were stored for 6 days in de-ionized water, acidic buffer I (pH 4.2), neutral buffer II (pH 7.0), or neutral buffer III (pH 7.0) containing porcine esterase. The specimens were transferred into fresh media every 48 h. Fluoride release was measured every 48 h. Vickers hardness of each five samples of every group was determined before storing the samples in media (baseline) as well as after storage for 24, 48, and 144 h in the various solutions. Dry-stored specimens served as control. RESULTS: The surface microhardness of all PMCs significantly decreased after storage in the various media. No significant differences, however, were found between samples of the same material stored in the various media for 6 days. In general, the highest fluoride quantity was released into the acidic buffer I except for Dyract AP, which segregated similar quantities of fluoride into buffer I and into de-ionized water. More fluoride was released into de-ionized water than into neutral buffers. Further, esterase treatment increased fluoride release from three PMCs. SIGNIFICANCE: Our results suggest that the action of salivary esterases may weaken the surface of polyacid-modified composite resin restorations. As a clinical consequence, wear may be enhanced and load resistance may be reduced. In addition, fluoride release from PMCs may be increased by hydrolytic enzymes in saliva and under acidic conditions.


Subject(s)
Compomers/chemistry , Analysis of Variance , Buffers , Composite Resins/chemistry , Drug Storage , Fluorides/chemistry , Glass Ionomer Cements/chemistry , Hardness , Hydrogen-Ion Concentration , Methacrylates/chemistry , Saliva/enzymology , Silicates/chemistry , Surface Properties
20.
Clin Oral Investig ; 3(1): 41-8, 1999 Mar.
Article in English | MEDLINE | ID: mdl-10522192

ABSTRACT

Purpose of this investigation was to determine the cytocompatibility of various periodontal dressing materials by means of human primary gingival fibroblasts (HGF), human osteoblast-like cells (HObl) derived from the alveolar bone, and permanent 3T3 mouse fibroblasts (3T3). Cell culture medium extracts (time periods of extraction: day 1 and between day 2 and day 8 after setting) as well as solid specimens of the following materials were investigated: Coe-pak, Voco pac, Peripac, and Barricaid. Responses of cultures exposed for 24 h and 48 h to these materials were monitored by the fluorescent dyes H33342 and sulforhodamin 101 as well as by light microscopy. It was found that most extracts of Voco pac, Peripac, and Barricaid did not inhibit growth of HGF. Coe-Pak, however, clearly reduced the proliferation of HGF compared to untreated controls. Peripac decreased growth of HObl whereas Coe-Pak, Voco pac, and Barricaid caused no cytotoxic alterations in any of the test assays. Contrary to HGF and HObl, 3T3 cells were much more irritated by the test materials. But the light-curing resinous material Barricaid reduced proliferation of 3T3-fibroblasts only slightly. Our data indicate that Barricaid is exceedingly cytocompatible, whereas all other materials revealed moderate or severe cytotoxic effects according to the cell type.


Subject(s)
Fibroblasts/drug effects , Gingiva/drug effects , Periodontal Dressings/adverse effects , 3T3 Cells , Animals , Cell Division/drug effects , Cells, Cultured , Eugenol/toxicity , Gingiva/cytology , Humans , Magnesium Oxide/toxicity , Mice , Osteoblasts/drug effects , Resins, Synthetic/adverse effects , Zinc Oxide/toxicity
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