183 research outputs found

    Characteristics of Particles and Debris Released after Implantoplasty: A Comparative Study

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    The work was supported by Graduate Periodontic, College of Dentistry, OUHSC and Department of Occupational and Environmental Health, Hudson College of Public Health, OUHSC. The work was also supported by the Spanish Government and the Ministry of Science and Innovation of Spain by research projects RTI2018-098075-B-C21 and RTI2018-098075-B-C22 (co-funded by the European Regional Development Fund (ERDF), a way to build Europe).Titanium particles embedded on peri-implant tissues are associated with a variety of detrimental effects. Given that the characteristics of these detached fragments (size, concentration, etc.) dictate the potential cytotoxicity and biological repercussions exerted, it is of paramount importance to investigate the properties of these debris. This study compares the characteristics of particles released among different implant systems (Group A: Straumann, Group B: BioHorizons and Group C: Zimmer) during implantoplasty. A novel experimental system was utilized for measuring and collecting particles generated from implantoplasty. A scanning mobility particle sizer, aerodynamic particle sizer, nano micro-orifice uniform deposit impactor, and scanning electron microscope were used to collect and analyze the particles by size. The chemical composition of the particles was analyzed by highly sensitive microanalysis, microstructures by scanning electron microscope and the mechanical properties by nanoindentation equipment. Particles released by implantoplasty showed bimodal size distributions, with the majority of particles in the ultrafine size range (<100 nm) for all groups. Statistical analysis indicated a significant difference among all implant systems in terms of the particle number size distribution (p < 0.0001), with the highest concentration in Group B and lowest in Group C, in both fine and ultrafine modes. Significant differences among all groups (p < 0.0001) were also observed for the other two metrics, with the highest concentration of particle mass and surface area in Group B and lowest in Group C, in both fine and ultrafine modes. For coarse particles (>1 m), no significant difference was detected among groups in terms of particle number or mass, but a significantly smaller surface area was found in Group A as compared to Group B (p = 0.02) and Group C (p = 0.005). The 1 first minute of procedures had a higher number concentration compared to the second and third minutes. SEM-EDS analysis showed different morphologies for various implant systems. These results can be explained by the differences in the chemical composition and microstructures of the different dental implants. Group B is softer than Groups A and C due to the laser treatment in the neck producing an increase of the grain size. The hardest implants were those of Group C due to the cold-strained titanium alloy, and consequently they displayed lower release than Groups A and B. Implantoplasty was associated with debris particle release, with the majority of particles at nanometric dimensions. BioHorizons implants released more particles compared to Straumann and Zimmer. Due to the widespread use of implantoplasty, it is of key importance to understand the characteristics of the generated debris. This is the first study to detect, quantify and analyze the debris/particles released from dental implants during implantoplasty including the full range of particle sizes, including both micro- and nano-scales.Graduate Periodontic, College of Dentistry, OUHSC and Department of Occupational and Environmental Health, Hudson College of Public Health, OUHSCSpanish Government RTI2018-098075-B-C21 and RTI2018-098075-B-C22 ( European Regional Development Fund (ERDF)

    Gingival crevicular fluid periostin levels in chronic periodontitis patients following nonsurgical periodontal treatment with low-level laser therapy

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    Objective: Periostin is a matricellular protein highly expressed in periosteum, periodontal ligament and is essential for tissue integrity and maturation. It plays a role in collagen fibrillogenesis and is downregulated in periodontal disease. Biostimulation utilizing low-level laser therapy (LLLT) influences periodontal ligament fibroblast proliferation. This study was conducted with the objective of estimating periostin levels in chronic periodontitis (CP) patients following LLLT as an adjunct to root surface debridement (RSD). Materials and Methods: Thirty periodontally healthy participants (Group I) and sixty CP participants were recruited. Based on the therapeutic intervention, CP patients were allocated to either RSD (Group II) or to RSD with LLLT (Group III) group. Clinical parameters and gingival crevicular fluid (GCF) periostin levels were assessed at the baseline and at the 3rd month. Results: Periostin levels were significantly lower in CP patients when compared to healthy individuals at the baseline (P < 0.01). Following nonsurgical periodontal treatment (NSPT), periostin levels significantly increased in both Group II and III, when compared to baseline values (P < 0.001). Comparison of mean periostin levels between both the treatment groups showed a significant increase in LLLT group than RSD at the 3rd month (P < 0.05). Conclusion: Within the limitations of the present study, LLLT application was found to have additional benefits over RSD with respect to clinical periodontal parameters and GCF periostin levels. Moreover, periostin may be used as a possible biomarker to evaluate the outcome following NSPT

    On the free-boundary for an elliptic inverse nonlocal problem arising in the nuclear fusion. A numerical approach

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    We consider a mathematical model related to the stationary regime of a plasma magnetically confined in a Stellarator device in the nuclear fusion. The mathematical problem may be reduced to an nonlinear elliptic inverse nonlocal two dimensional free{boundary problem. The nonlinear terms involving the unknown functions of the problem and its rearrangement. Our main goal is to determinate the existence and the estimate on the location and size of region where the solution is nonnegative almost everywhere (corresponding to the plasma region in the physical model

    An Antimaximum Principle for a Degenerate Parabolic Problem.

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    Beginning with the work of Clement and Peletier , various kinds of anti- maximum principles have been established for linear and nonlinear elliptic operators; for linear elliptic operators, see e.g. Alziary, Fleckinger, and Takac, Sweers, Takac, and the references therei

    Preliminary insight into the periostin leverage during periodontal tissue healing

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    BackgroundTissue repair and regeneration is assisted by the efficient coordination of cell and extracellular matrix interactions mediated by matricellular molecules such as periostin. Given its high expression around the teeth, the periodontal organ represents an ideal system to capture the protein dynamics during wound healing.MethodsAn observational prospective case–control study was designed to characterize periostin changes over time after periodontal surgery in tissue, oral fluids and serum by histological, protein and mRNA analyses.ResultsHistological analysis showed lower periostin with a diffuse local distribution pattern in disease patients. Levels of periostin in gingival crevicular fluid (GCF) increased over time for both groups, more noticeably in the periodontitis subjects. A transient and subtle change in circulating periostin levels was also noticed. The mRNA periostin levels contrasted with the protein levels and may indicate the underlying post‐transcriptional regulatory process during chronic inflammation. Levels of known periodontal disease biomarkers such as IL‐β, IL1‐α, TNF‐α, MIP‐1α and CRP served as tissue stability markers and complemented the clinical parameters recorded.ConclusionThe transient local increase in GCF periostin after eliminating the local etiology in periodontally affected sites suggests its importance in the maturation and stability of the connective tissue. The decreasing levels observed as the tissue healed highlight its spatial/temporal significance.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/113755/1/jcpe12432.pd

    Expression of Musashi-1 During Osteogenic Differentiation of Oral MSC: An In Vitro Study

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    Supplementary materials can be found at https://www.mdpi.com/1422-0067/20/9/2171/s1Background: Musashi-1 (MSI1) is a negative regulator of mesenchymal stromal cell (MSC) differentiation which in turn favors cell proliferation. However, little is known about its expression by MSC from the oral cavity and in the context of osteogenic differentiation. Aim: The aim of this study was to analyze the expression of MSI1 in the context of osteogenic differentiation of MSC derived from the oral cavity. Material/methods: For this in vitro study, MSC were isolated from six different origins of the oral cavity. They were extensively characterized in terms of proliferative and clonogenicity potential, expression of stemness genes (MYC, NANOG, POU5F1, and SOX2), expression of surface markers (CD73, CD90, CD105, CD14, CD31, CD34, and CD45) and adipo-, chondro- and osteogenic differentiation potential. Then, osteogenic differentiation was induced and the expression of MSI1 mRNA and other relevant markers of osteogenic differentiation, including RUNX2 and Periostin, were also evaluated. Results: Cell populations from the alveolar bone (pristine or previously grafted with xenograft), dental follicle, dental germ, dental pulp, and periodontal ligament were obtained. The analysis of proliferative and clonogenicity potential, expression of the stemness genes, expression of surface markers, and differentiation potential showed similar characteristics to those of previously published MSC from the umbilical cord. Under osteogenic differentiation conditions, all MSC populations formed calcium deposits and expressed higher SPARC. Over time, the expression of MSI1 followed different patterns for the different MSC populations. It was not significantly different than the expression of RUNX2. In contrast, the expression of MSI1 and POSTN and RUNX2 were statistically different in most MSC populations. Conclusion: In the current study, a similar expression pattern of MSI1 and RUNX2 during in vitro osteogenic differentiation was identified.The authors of this investigation were partially supported by Research Groups #CTS-138 (F.O.) and #CTS-1028 (M.P.-M., P.G.-M.) (Junta de Andalucía, Spain), a grant from MIS Implant Technologies Ltd. (M.P.-M., D.A.-G., P.G.-M.), the Youth Employment Initiative (YEI) from the European Commission (R.S.-U.), and the Instituto de Salud Carlos III, Spain (www.isciii.es) and Fondo Europeo de Desarrollo Regional (FEDER, from the European Union), through the research grants PI15/00794 and CPII15/00032 (P.A)

    Modelization of an experimental solar test box equipped with a water-flow based window

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    A study on a water- ow window installed in a test box is presented. This window is composed of two glass panes separated by a chamber through water ows. The ow of water comes from an isolated tank which contains heat water. In order to fully evaluate the water- ow window performance for different room and window sizes, locations and weather conditions, a mathematical model of the whole box is needed. The proposed model, in which conduction heat transfer mechanism is the only considered, is one dimensional and unsteady based upon test box energy balance. The effect of the heat water tank, which feeds the water- ow window, is included in the model by means of a time delay in the source term. Although some previous work about moving uid chamber has been developed, air was used as heat transfer uid and no uid storage was considered. Finally a comparison between the numerical solution and the obtained experimental data is done

    Price Formation and Real Estate Characteristics Residential Real Estate, Lisbon - Portugal

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    Análisis del proceso de formación de precios en el mercado residencial de Lisboa desde el punto de vista de la eliminación de los aspectos subjetivos de la apreciación por el tasador de las características de los inmueble
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