Composite-induced toxicity in human gingival and pulp fibroblast cells

Objective. The most important requirement for a material to be used in medical applications is its biocompatibility. Dental composite materials come into direct contact with oral tissues, especially gingival and pulpal cells. This study was performed to evaluate possible DNA damage in cells of human origin exposed to dental composites in vitro using a cytogenetic assay. Materials and methods. Two composite resins (Vertise Flow, Kalore) were tested on human gingival and pulp fibroblasts using the acridine orange/ethidium bromide viability staining and alkaline comet assay. Cultures were treated with polymerized composites in two different concentrations (20 mg/ml, 40 mg/ml) for 14 days. Chi-square and Kruskall-Wallis non-parametric test were used for the statistical analysis (p < 0.05). Results. Significant cytotoxicity was observed for 40 mg/ml of Vertise Flow in both cultures, while Kalore (40 mg/ml) showed cytotoxic effect only on human pulp fibroblasts. A significant level of DNA damage was detected for both materials and concentrations, in both cell cultures. Conclusion. If the two cell cultures are compared, the pulp cells were more sensitive to the cyto/genotoxic effects of dental composites. Based on the results, one can conclude that the use of tested materials may cause cellular damage in gingival and pulp fibroblasts in vitro.     

Cytotoxicity of coated and uncoated fibre-reinforced composites

Objective. Currently, there are many fibre-reinforced composites (FRCs) available which differ in the type and volume fraction of fibres, pre-treatment of fibres and matrix composition. The aims of this in vitro investigation were to determine whether there is a difference in biocompatibility of FRCs and if coating FRCs with resin composites influences their cytotoxic potential. Materials and methods. Five different FRC materials were tested which were either uncoated or coated with flowable or viscous resin composite. Artificial saliva extracts were prepared according to USP-XXIII and ISO-10993 to determine cytotoxicity by testing cell viability and growth of primary human gingival fibroblasts (HGF) using MTT assay, LIVE/DEAD® assay and cell proliferation assay. The influence of eluates on fibres of the cytoskeleton was investigated by vimentin, tubulin and actinin immunostainings. A two-way ANOVA followed by Scheffe's post-hoc test, which included the factors FRC material and coating procedure, was performed to assess cytotoxicity. Results. All extracts of FRC materials displayed minor cytotoxic potential on HGF cell viability, cell proliferation and integrity of the cytoskeleton. The type of FRC material significantly influenced cell viability (MTT assay) (p < 0.0001), whereas neither the presence of a coating nor the type of coating material resulted in altered cell viability. Distribution and organization of cytosolic fibres was not affected after HGF exposure to eluates. Conclusions. There is a lack of knowledge about the leaching behaviour of commonly available fully pre-impregnated FRCs and their interactions with coating materials. The coating of FRCs with resin composite materials did not impact biocompatibility.     

Influence of alloying elements on cellular response and in-vitro corrosion behavior of titanium-molybdenum-chromium alloys for implant materials

PurposeNot all elements with β-stabilizing properties in titanium alloys are suitable for biomaterial applications, because corrosion and wear processes release the alloying elements to the surrounding tissue. Chromium and molybdenum were selected as the alloying element in this work as to find balance between the strength and modulus of elasticity of β-titanium alloys. This study aimed to investigate the effect of Titanium-10Molybdenum-10Chromium (Ti-10Mo-10Cr), Titanium-10Chromium (Ti-10Cr) and Titanium-10Molybdenum (Ti-10Mo) on the elemental leachability in tissue culture environment and their effect on the viability of human gingival fibroblasts (HGFs).MethodsEach alloy was immersed in growth medium for 0–21 days, and the elution was analyzed to detect the released metals. The elution was further used as the treatment medium and exposed to seeded HGFs overnight. The HGFs were also cultured directly to the titanium alloy for 1, 3 and 7 days. Cell viability was then determined.ResultsSix metal elements were detected in the immersion of titanium alloys. Among these elements, molybdenum released from Ti-10Mo-10Cr had the highest concentration throughout the immersion period. Significant difference in the viability of fibroblast cells treated with growth medium containing metals and with direct exposure technique was not observed. The duration of immersion did not significantly affect cell viability. Nevertheless, cell viability was significantly affected after 1 and 7 days of exposure, when the cells were grown directly onto the alloy surfaces.ConclusionsWithin the limitation of this study, the newly developed β-titanium alloys are non-cytotoxic to human gingival fibroblasts.     

Fabrication of enamel-like structure on polymer-infiltrated zirconia ceramics

ObjectivesThe aim of this study is to improve the biological and mechanical properties of zirconia-based PICN (polymer-infiltrated-ceramic-network) materials by fabrication an enamel-like structure on its surface.MethodsFluorapatite (FA) arrays were fabricated on zirconia discs by hydrothermal treatment. After polymer infiltration, an enamel-like structure was obtained on zirconia-based PICN materials. Effects of hydrothermal treatment conditions on the FA arrays were investigated by XRD, FTIR and SEM. Human gingival fibroblast cells (HGFs) and Escherichia coli (E. coli) were used to evaluate the cytocompatibility and antibacterial properties. Nanoindentation method was employed to determine elastic modulus and hardness.ResultsA facile and pervasive method was developed in this study to fabricate an enamel-like structure constituted of controlled FA arrays and interstitial resin on zirconia-based PICN materials. The obtained FA arrays can significantly promote the adhesion and proliferation of human gingival fibroblasts (HGFs), and further effectively inhibit the growth of Escherichia coli. Owing to the hierarchical structure, the enamel-like structure has achieved a hardness of 1.79 GPa and a lower Young’s modulus of 37.4 GPa.SignificancesThe enamel-like structure, with excellent biological and mechanical properties, is promising for various applications in dentistry.     

水蛭素对牙龈成纤维细胞碱性成纤维细胞生长因子和转化生长因子-β1表达的影响

目的 观察水蛭素对人牙龈成纤维细胞（HGFs）碱性成纤维细胞生长因子（bFGF）及转化生长因子-β1（TGF-β1）表达变化的规律,探讨水蛭素影响牙龈改建的可能作用机制。方法 体外培养并鉴定HGFs,利用不同浓度的水蛭素分别作用于正常（对照组）和受长期机械外力作用后增生的HGFs（实验组）,通过实时定量聚合酶链反应法和免疫细胞化学法检测TGF-β1及bFGF的表达。结果 未加入水蛭素时,受长期机械外力作用后,实验组促进HGFs增殖胶原合成的TGF-β1表达升高,而抑制胶原合成的bFGF表达降低（P<0.05）。加入水蛭素干预增生的HGFs后,可正向调节bFGF表达,而负向调节TGF-β1的表达（P<0.05）。结论 外力作用干扰了HGFs胶原合成与降解之间的平衡,水蛭素可能通过调节这一平衡而促进牙龈改建过程。     

纤维连接蛋白修饰的微沟槽钛片对人牙龈成纤维细胞活性影响的研究

目的:研究微沟槽钛片表面经三氟代乙烷磺酰氯激活并修饰纤维粘结蛋白(fibronectin,FN)后对人牙龈成纤维细胞(HGF)活性的影响。方法:将FN修饰于经过激活的微沟槽钛表面,XPS分析材料表面元素组成;使用cck8法检测HGF接种材料表面6 h、12 h、1 d、3 d、5 d、7 d后的细胞增值率;荧光染色观察接种3 d时的细胞数量及形态。I型胶原纤维ELISA实验及Real-time PCR检测接种5 d时材料表面对HGF分泌功能的差异。结果:在实验观察的6个时间段实验组材料细胞增值率高于对照组(P<0.05)。3 d时HGF在实验组材料表面的伸展率高于空白组(P<0.05)。5 d时FN修饰的两组材料上的细胞外I性胶原纤维的数量及mRNA的表达水平较空白组高(P<0.05)。结论:经三氟代乙烷磺酰氯处理修饰FN的微沟槽钛片可促进HGF的增殖、伸展及分泌功能。     

Focal adhesion linker proteins expression of fibroblast related to adhesion in response to different transmucosal abutment surfaces

PURPOSE

To evaluate adherence of human gingival fibroblasts (HGFs) to transmucosal abutment of dental implant with different surface conditions with time and to investigate the roles of focal adhesion linker proteins (FALPs) involved in HGFs adhesion to abutment surfaces.

MATERIALS AND METHODS

Morphologies of cultured HGFs on titanium and ceramic discs with different surface were observed by scanning electron microscopy. Biocompatibility and focal adhesion were evaluated by ultrasonic wave application and cell viability assay. FALPs expression levels were assessed by RT-PCR and western blot.

RESULTS

There seemed to be little difference in biocompatibility and adhesion strength of HGFs depending on the surface conditions and materials. In all experimental groups, the number of cells remaining on the disc surface after ultrasonic wave application increased more than 2 times at 3 days after seeding compared to 1-day cultured cells and this continued until 7 days of culture. FALPs expression levels, especially of vinculin and paxillin, also increased in 5-day cultured cells compared to 1-day cultured fibroblasts on the disc surface.

CONCLUSION

These results might suggest that the strength of adhesion of fibroblasts to transmucosal abutment surfaces increases with time and it seemed to be related to expressions of FALPs.     

Evaluation of the biological behaviour of various dental implant abutment materials on attachment and viability of human gingival fibroblasts

ObjectiveThis study aimed to investigate the biological effects of yttria-stabilized zirconia (Y-TZP) compared to other dental implant abutment materials, i.e. lithium disilicate (LS2) and titanium alloy (Ti), as well as the effects of aging of Y-TZP on viability/proliferation and attachment properties of Human Gingival Fibroblasts (HGFs).MethodsCylindrical specimens of each material were prepared as per manufacturer’s instructions. Y-TZP specimens were divided into three groups: 1. no aging (Zr0), 2. aging for 5 h, 134 °C, 2 bars, 100% humidity (Zr5), 3. aging for 10 h under the same conditions (Zr10). Surface roughness was evaluated by optical profilometry; cell metabolic activity/viability by MTT assay, morphological changes by Scanning Electron Microscopy (SEM) and ratio of live/dead cells by confocal microscopy.ResultsResults showed statistically significant reduction of HGF metabolic activity/viability in contact with Y-TZP after aging. Nevertheless, non-aged zirconia showed no significant differences compared with LS2, Ti and control cultures. In contrast, significant stimulation of cell metabolic activity/viability was observed in HGFs exposed to LS2 eluates. Differential morphological patterns were observed for HGF in contact with different materials/treatments, with obviously increased number of dead cells and sparser distribution of HGFs cultured on Zr10 specimens. These effects were not correlated with surface topography, since Y-TZP aging did not alter surface micro-roughness.SignificanceThese findings indicate that Y-TZP shows comparable biological properties to Ti and LS2 as implant abutment material. Nevertheless, Y-TZP aging might influence gingival cell attachment and proliferation properties, providing an alert to a potentially negative effect on the long-term maintenance of gingival architecture.     

Effects of HEMA on Nrf2-related gene expression using a newly developed 3D co-culture model of the oral mucosa

Objective2-Hydroxyethyl methacrylate (HEMA) is a component of many resin-modified materials and elutes from dental restorations into the oral cavity. Objective of our investigation was to determine the impact of HEMA on oral keratinocytes (OKF6/TERT2) and gingival fibroblasts (HGFs) in a newly established 3D co-culture model (3D-CCM) and to analyze the permeability of OKF6/TERT2 cells for HEMA.MethodsWell-characterized 3D-CCMs, consisting of confluent OKF6/TERT2 cells on cell culture inserts above HGF-containing collagen gels, were treated supra-epithelial with HEMA. Mass spectrometry was used to measure the supra- and sub-epithelial distribution of HEMA after 24 h. The impact of HEMA on nuclear factor erythroid 2-related factor 2 (Nrf2) target genes was measured by qRT-PCR and western blot analysis.ResultsMass spectrometry showed that HEMA was evenly distributed above and below the keratinocyte layer after 24 h. Analyzed target genes of Nrf2 were induced in both cell types on the mRNA-level but less pronounced in HGFs. On the protein-level, both cell types showed similar effects: At 5 mM HEMA, heme oxygenase-1 was induced 5.1-fold in OKF6/TERT2 cells and 4.1-fold in HGFs. NAD(P)H quinone dehydrogenase-1 was approximately induced 1.85-fold in both cell types.SignificanceOur 3D-CCM is suitable to analyze the biocompatibility of dental materials due to an improved simulation of the oral mucosa compared to monolayer cultures. Our results indicate that HEMA is able to penetrate a dense layer of keratinocytes and to activate the cellular oxidative defense response. This may be due to the activation of the Nrf2-pathway in both cell types.     

Glycated Collagen Stimulates Differentiation of Gingival Myofibroblasts

Background: Glucose‐derived metabolites may alter the structure and biologic properties of important proteins in periodontium, such as collagens. As a consequence, it is possible that collagen‐binding cells may change their phenotypic traits. Although the glucose‐derived product methylglyoxal (MGO) has been detected in periodontal lesions, the precise effect of collagen glycation on gingival connective tissue biology is not fully understood. The present study evaluates whether collagen glycation by MGO may affect phenotypic properties and remodeling capacity of human gingival fibroblasts (HGFs). Methods: Primary cultures of HGFs were grown on Type I collagen matrices previously treated with MGO. Cell cultures were tested for cell viability, apoptosis, α‐smooth muscle actin (SMA), fibronectin (FN) production, and collagen remodeling. Mechanical properties and morphology of MGO‐treated collagen gels were evaluated using rheometry and atomic force microscopy. Statistical analysis was performed by Kruskal‐Wallis and Mann‐Whitney U tests. Results: MGO‐treated collagen did not affect cell viability or apoptosis. In addition, MGO did not induce significant changes in morphology or mechanical properties of the collagen matrix. However, MGO‐treated collagen stimulated an increase in the myofibroblast marker α‐SMA, production and assembly of FN, and contraction of collagen matrices. Moreover, use of a triple‐helical peptide that reconstitutes the collagen‐binding domain for integrins GFOGER reverted the assembly of FN induced by MGO‐treated collagen. Conclusions: The present study shows that collagen glycation by MGO stimulates differentiation of myofibroblasts and production and assembly of FN. These responses may alter the homeostatic balance and wound‐healing response of gingival connective tissues affected by diabetes mellitus or aging.     

Identification of Quercitrin as a Potential Therapeutic Agent for Periodontal Applications

Background: Flavonoids are natural phenolic compounds with antioxidant, anti‐inflammatory, and antimicrobial capacity. This study aims to investigate the effects of different flavonoids for potential use in periodontal applications. Methods: Cultures of Staphylococcus epidermidis or primary human gingival fibroblasts (HGFs) were treated with different doses of chrysin, diosmetin, galangin, quercitrin, and taxifolin. The effect of these molecules was evaluated on S. epidermidis growth rate and HGF viability, gene expression, collagen production, reactive oxygen species (ROS) levels, wound healing, and production of matrix metalloproteinase (MMP)‐1 and tissue inhibitor of MMP‐1 (TIMP1). Results: Among all the screened flavonoids, quercitrin showed the most promising biologic effects, in both HGFs and S. epidermidis. Thus, quercitrin was not toxic for HGFs; increased collagen IIIα1 and decorin levels; downregulated interleukin‐6 messenger RNA levels; decreased the expression of profibrotic markers during wound healing; decreased ROS levels in basal and stimulated conditions; and decreased the MMP1/TIMP1 ratio. Quercitrin also decreased the bacterial growth rate. Conclusions: Results suggest that quercitrin could contribute to protect and recover the integrity of gingival tissues, thus displaying a potential use for periodontal disease treatment or to functionalize dental implant abutments to improve soft tissue integration. Further studies are required to confirm the role of quercitrin in gingival tissues.     

Effect of phenytoin on collagen accumulation by human gingival fibroblasts exposed to TNF-alpha in vitro

OBJECTIVE: Tumor necrosis factor (TNF)-alpha is associated with chronic gingival inflammation and reported to induce gingival overgrowth (GO), while phenytoin (PHT) is also known to be a causative agent of GO. We examined the synergistic effect of PHT and TNF-alpha on collagen metabolism in human gingival fibroblasts (HGFs). MATERIALS AND METHODS: HGFs were cultured with TNF-alpha and PHT. Quantitative real-time RT-PCR was employed to determine the mRNA levels for collagen, matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs) and integrin subunits. Cellular collagen endocytosis was determined using a flow-cytometry. RESULTS: The proliferation of HGFs was not affected by TNF-alpha or PHT individually, whereas both synergistically increased collagen accumulation in HGFs. Further, collagen mRNA expression was not increased by TNF-alpha or PHT, although together they markedly prevented cellular collagen endocytosis, associated with the suppression of alpha2beta1-integrin mRNA expression. The mRNA expression of MMP-1 and-2 was suppressed by PHT, while TIMP-1 mRNA expression was enhanced by both TNF-alpha and PHT. CONCLUSION: Our results suggest that TNF-alpha and PHT together cause impaired collagen metabolism by suppression of enzymatic degradation with MMPs/TIMP-1 and integrin-mediated endocytosis. These synergistic effects may also be involved in TNF-alpha- and PHT-induced collagen accumulation, leading to GO.     

TiO2-PEEK-CRGDS材料制备及抗牙龈卟啉单胞菌活性和细胞活性分析

目的:将聚醚醚酮(polyetheretherketone,PEEK)复合材料用纳米二氧化钛(TiO2)和CRGDS肽改性,制备得到TiO2-PEEK-CRGDS,评价其抗牙龈卟啉单胞菌活性和细胞活性.方法:使用等离子体浸没离子注入法(plasma-im-mersion ion implantation,PⅢ)制备Ti...     

CD99 ligation induces intercellular cell adhesion molecule-1 expression and secretion in human gingival fibroblasts

ObjectiveTo examine CD99 expression and its functional role in ICAM-1 induction in human gingival fibroblasts (HGFs) and human gingival epithelial cells (HGECs) by activating cells with anti-CD99 monoclonal antibody, MT99/3.BackgroundEngagement of CD99 with agonistic antibodies has been shown to regulate immune responses, cell adhesion and migration, and cell death in several studies. Particularly, this engagement results in transendothelial migration of leukocytes mediated by intercellular adhesion molecule-1 (ICAM-1) induction in endothelial cells.MethodsTotal mRNA and protein were isolated from HGFs and HGECs for analyses of CD99 and ICAM-1 expression. Surface expression of CD99 and ICAM-1 was analysed by flow cytometry, and the detection of soluble ICAM-1 was assayed by immunoprecipitation and ELISA.ResultsCD99 surface expression was constitutive on HGFs to a greater extent than that on HGECs. CD99 ligation with MT99/3 induced ICAM-1 mRNA expression in HGFs, but not in HGECs. Interestingly, CD99 ligation led to an increased level of soluble ICAM-1 detected in culture supernatant, whereas interleukin-1β (IL-1β) treatment induced expression of membrane-bound ICAM-1. Furthermore, ICAM-1 induction by CD99 engagement was demonstrated to involve the activation of the p50 subunit of nuclear factor-kappaB (NF-κB), extracellular signal-regulated kinase, and p46 c-Jun N-terminal kinase that differed from that by IL-1β treatment.ConclusionOur study has shown the involvement of CD99 ligation in the up-regulation of ICAM-1 expression and its secretion in gingival fibroblasts, which may be essential for better understanding of the pathogenesis of periodontal disease.     

In vitro cytotoxicity of different thermoplastic materials for clear aligners

Objectives:To investigate the in vitro cytotoxicity of different thermoplastic materials for clear aligners on human primary gingival fibroblasts (HGFs).Materials and Methods:Four materials for clear aligners were considered in this study: Duran (Scheu-Dental GmbH, Iserlohn, Germany), Biolon (Dreve Dentamid GmbH, Unna, Germany), Zendura (Bay Materials LLC, Fremont, CA, USA), and SmartTrack (Align Technology, San Jose, CA, USA). Three out of four materials (Duran, Biolon, Zendura) were assessed as thermoformed and nonthermoformed, whereas the SmartTrack was assessed only as thermoformed. The samples were placed at 37°C in airtight test tubes containing Dulbecco''s Modified Eagle''s Medium (DMEM; 0.1 mg/mL) for 14 days. The cell viability of HGFs cultured with this medium was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Data were analyzed by means of one-way and two-way analysis of variance and post hoc tests (α = 0.05).Results:Each material exhibited a slight cytotoxic effect after 14 days. The highest cytotoxicity level on HGFs was achieved by Biolon (64.6% ± 3.3 of cell viability), followed by Zendura (74.4% ± 2.3 of cell viability), SmartTrack (78.8% ± 6.3 of cell viability), and finally Duran (84.6% ± 4 of cell viability), which was the least cytotoxic. In the comparison between nonthermoformed and thermoformed materials for Duran, Biolon, and Zendura, the thermoformed materials showed the highest level of cytotoxicity (P < .001).Conclusions:Under the experimental conditions of this study, all the materials for clear aligners presented a slight cytotoxicity. Biolon was the most cytotoxic and the thermoforming process increased the cytotoxicity of the materials.     

Celecoxib对细菌脂多糖促牙龈成纤维细胞生长抑制作用的研究

目的观察celecoxib对细菌脂多糖(Lipopolysaccharides,LPS)促人牙龈成纤维细胞(humangingivalfibroblasts,HGFs)生长作用的影响。方法采用细胞活性和增殖水平测定(WST)实验检测LPS及celecoxib对体外培养的HGFs生长的影响。结果LPS可促进HGFs的生长,其作用效果随LPS剂量的增加而增强,1.0,12.5、100.0LPS处理后HGFs的细胞生长率与阴性对照组相比分别为126.1%,164.5%和215.5%;celecoxib对LPS促HGFs生长的现象有明显的抑制作用,其抑制作用呈剂量依赖性关系,12.5μmol/L到100μmol/L的celecoxib处理可使LPS刺激的HGFs生长率降低至对照组的76.3%~30.3%。结论LPS可促进HGFs的生长;celecoxib能抑制LPS对HGFs的生长刺激作用。     

Development of novel dental restorative composites with dibasic calcium phosphate loaded chitosan fillers

The incorporation of antimicrobial agents in restorative dental composites has the potential to slow the development of carious lesions.ObjectiveThe objectives of the present study were to develop experimental composite resins with chitosan or chitosan loaded with dibasic calcium phosphate anhydrous (DCPA) particles and to demonstrate their antimicrobial potential without loss of mechanical properties or biocompatibility.MethodsChitosan and chitosan/DCPA particles were synthetized by the electrospray method. Experimental composites were formulated by adding 0, 0.5, or 1.0 wt% particles into a resin matrix along with 60 wt% barium glass. The degree of conversion and mechanical properties were measured after 1 and 90 days of aging in water after photoactivation. Cytotoxicity and genotoxicity were evaluated using fibroblasts from dental pulp in conditioned medium. The antimicrobial activity against Streptococcus mutans was assessed by crystal violet biofilm assay.ResultsThe experimental restorative composites were not found to be cytotoxic or genotoxic, with cell viability of 93.1 ± 8.0% (p = 0.328) and 3.0 ± 0.8% micronucleus per group (p = 0.1078), respectively. The antimicrobial results showed that all composites with approximately 20% less biofilm (p < 0.001) relative to the control. No chitosan release was detected from the composites, suggesting direct contact of the bacteria with exposed chitosan particles on the surface was responsible for the observed antimicrobial effect. The addition of the chitosan and chitosan/DCPA submicrometer (<250 nm average diameter) particles to restorative composites did not change the degree of conversion, flexural strength, elastic modulus and fracture toughness compared to the control group after 90 days aging in water.SignificanceIt can be concluded that the addition of chitosan or chitosan/DCPA particles in the restorative composites induced antimicrobial activity without compromising the mechanical properties or biocompatibility of the composites.     

Stimulatory effect of Aggregatibacter actinomycetemcomitans DNA on proinflammatory cytokine expression by human gingival fibroblasts

ObjectiveWhile different virulence factors have been reported of Aggregatibacter actinomycetemcomitans (Aa), there is little information about the stimulatory effect of its DNA. The main purpose of this study was to assess the inflammatory response of human gingival fibroblasts (HGFs) stimulated with A. actinomycetemcomitans DNA.DesignCytokine levels of IL-6, IL-1α and TNF-α were measured on the supernatant of HGFs activated with 10, 25, 50 and 100 μg/ml DNA of Aa during 24 h. Primary cultures of HGFs were infected with Aa and its DNA at different times and concentrations to compare its cytotoxic effect. Cell damage and adhesion of Aa to HGFs were evaluated under light microscopy and Scanning electron microscopy respectively.ResultsThere was a statistical difference (p < 0.05) in cytokine expression in HGFs activated by bacterial DNA with a dose dependent on IL-6 expression and a significantly elevated expression of IL-1α and TNF-α compared to Human DNA negative control. Substantial morphological alterations were observed after infection of A. actinomycetemcomitans in HGFs but not with bDNA exposure. Aggregatibacter actinomycetemcomitans showed a high rate of adhesion and cell damage to HGFs after 30 min.ConclusionsGenomic DNA of A. actinomycetemcomitans could be a factor in the pathogenesis of periodontitis that might play a major role in the inflammatory response.     

Response of two gingival cell lines to CAD/CAM composite blocks

ObjectiveThis study aimed to investigate the influence of CAD/CAM composite materials on human gingival fibroblasts (HGF) and gingival keratinocytes (HGK).MethodsFour materials were investigated: two resin-composite blocks (RCB), Grandio Blocs (GR) and Block HC (HC); one polymer-infiltrated ceramic network (PICN) (Enamic, EN); and one conventional resin-composite, Grandioso (GND). HGF and HGK were cultured as per the supplier’s protocol (ATCC, UK). Cell proliferation and cytotoxicity were evaluated at 1, 3, 5 and 10 days using LDH and Alamar Blue assays. Indirect immunostaining was used to assess the Caspase-3 activity. Data were analysed via two-way ANOVA, one-way ANOVA and Tukey’s post hoc test (α = 0.05 for all tests).ResultsThere was significant difference in cell proliferation of the HGK and HGF cells in contact with different composite materials but no significant differences in their cytotoxicity. There was a significant effect on cell proliferation and cytotoxicity with different exposure times, for each type of resin-composite. HGF cell proliferation was higher than HGK with almost all investigated materials and at all time points. No Caspase-3 activity was detected in either cell lines.SignificanceHGK proliferation and cytotoxicity appeared to be more influenced by composite materials compared to HGF, demonstrating EN cytotoxic effects in HGK. Different manufacturing techniques of resin-composites (photo curing versus heat/pressure curing) had no significant effect on their biocompatibility.     

多孔磷酸三钙-羟基磷灰石对人牙龈成纤维细胞黏附行为的影响

目的　研究多孔磷酸三钙 羟基磷灰石 (tricalcium phosphate hydroxyapatite ,TCP HA)复合材料对人牙龈成纤维细胞黏附行为的影响。方法　应用离子束辅助沉积法在纯钛试件表面制备多孔TCP HA复合涂层材料和羟基磷灰石 (hydroxyapatite,HA)涂层材料 ,定量对比人牙龈成纤维细胞在涂层和未涂层材料表面初期黏附、增殖、细胞铺展面积、细胞外基质和黏着斑形成的情况。结果　TCP HA和HA涂层材料表面黏附的细胞数、细胞铺展面积高于纯钛未涂层组 ,差异有显著性(P <0 0 5 ) ,黏着斑的形成早于未涂层组 ;TCP HA表面黏附的细胞数和Ⅰ型胶原的形成都高于纯钛未涂层组和HA涂层组。在培养 2 4h后TCP HA组表面黏附细胞数为 198 1± 2 7 7,Ⅰ型胶原形成的荧光强度为 15 4 10± 31 5 6 ,同纯钛组表面的细胞数 ( 12 5 1± 2 9 9)和Ⅰ型胶原荧光强度( 132 6 3± 35 2 6 )相比 ,差异有显著性 (P <0 0 5 )。结论　与纯钛未涂层和HA涂层材料相比 ,多孔TCP HA复合涂层材料更有利于人牙龈成纤维细胞的初期黏附 ,具有更良好的生物相容性