Comparative surface detail reproduction for elastomeric impression materials: Study on reproducibility performance.

For dental impression of a prepared tooth, the goal is a void-free negative representation from which an accurate cast of a tooth and its surrounding tissue can be reproduced. This in-vitro study assessed and compared the reproduction accuracies of surface detail obtained with three different dental elastomeric impression materials: vinyl polysiloxane (VPS), vinyl polyether silicone (VPES), and polyether (PE). A stainless-steel model with two abutments was used, with impressions taken 10 times for each material, for 20 abutment impressions per group, using a two-phase, one-step technique (heavy body/light body). The impressions were removed and assessed for numbers of enclosed voids and open voids visible on the surface. The defect frequency was 95% for impressions with the VPS and VPES materials, and 30% for the PE material. No significant differences were seen for number of impressions with defects for VPS versus VPES. Significant differences were seen for VPS and VPES versus the PE material (P <.05). No significant differences were seen for the defect type distributions across these three impression materials. The PE impression material showed better accuracy for reproduction of surface detail of these dental impressions compared to the VPS and VPES impression materials.

Isotopic biomonitoring of N pollution in rivers embedded in complex human landscapes.

The dynamic and hierarchical structure of rivers, together with disruption of the natural river continuum by human activities, makes it difficult to identify and locate sources of nutrient pollution affecting receiving waters and observe its dispersion, thus impairing monitoring efforts. The identification of reliable indicators of anthropogenic nitrogen inputs in catchments is therefore key to achieving effective management of polluted rivers. We tested the capacity of N isotopic signatures (δ15N) of epilithon and snails to provide useful indications of organic and inorganic anthropogenic N inputs in three Mediterranean rivers differing in terms of surrounding land use and physicochemical conditions. We used a combined approach based on (i) analysis of nutrient concentrations in water, (ii) CORINE land cover classification and drainage patterns in catchments and (iii) isotopic analysis of river biota to verify whether isotopic variations were indicative of anthropic activities in the watershed, the associated alteration of water quality, and the consequent impact on snail abundance and diversity. Variation in the δ15N of epilithon within and between rivers reflected localised and diffuse N inputs from inorganic and organic sources. Negative epilithon δ15N values (<0‰) indicated inorganic pollution from agriculture. Values between 4‰ and 8‰ and those above 8‰ respectively indicated moderate organic pollution from urban areas, and high organic pollution, mostly from waste waters. The diversity and abundance of snails decreased with increasing water pollution. While their isotopic variations reflected between-river differences, they failed to indicate within-river variations in anthropogenic N inputs, since the proportion of epilithon in their diet varied along the rivers. Concluding, epilithon was a reliable indicator of anthropogenic N sources across a wide range of nutrient concentrations and anthropogenic inputs, and the proposed approach allowed us to determine the nature of nitrogen pollutants, their sources, location and dispersion along rivers embedded in complex human landscapes.

A 10-year retrospective comparative human study on screw-retained versus cemented dental implant abutments.

The aim of this 10-year retrospective study was to evaluate the long-term reliability, survival rate and mechanical and biological complications of single-crown implant rehabilitations with two different types of fixture-abutment connections: screw-retained abutments (SRAs) with internal hexagonal connection, and cemented retained abutments (CRAs). A total of 300 single implant-supported crowns were analysed, which had been inserted between 2004 and 2007. Patients were classified according to two groups: the SRA group (n = 150) and the CRA group (n = 150). The primary outcome was marginal bone loss (MBL) on peri-apical radiographs. Bleeding on probing (BOP) and probing depth (PD) were also evaluated. Moreover, prosthetic complications were recorded. Analysis of variance (ANOVA) was used to evaluate the differences between the groups. The overall implant failure rate was 4.2%. The overall positive BOP index was 81.9% of the sites under investigation, as 83.4% for SRA and 80.4% for CRA. Moreover, >5 mm PD demonstrated a rate of 21.0% for CRA, and 13.8% for SRA. The primary outcome of mean MBL was 2.09±1.07 mm for SRA and 1.54±1.20 mm for CRA. Analysis of variance of MBL showed statistical significance for the difference between these two groups (P less than 0.001). For the mechanical aspects, an overall 12.5% of complications occurred. No implant or abutment fractures were recorded. Although complications occurred, the results from this 10-year retrospective study show that these two methods have positive long-term follow-up. With MBL significantly greater for the SRA group than the CRA group, the clinical use of CRA is encouraged in terms of the lower bone resorption rate.

Immunohistochemical study of osteopontin in oral squamous cell carcinoma allied to fractal dimension.

The aim of the study was to consider a possible correlation between the intensity of expression of osteopontin and grading established by the pathologist. Furthermore, a correlation was investigated between the increase of fractal dimension and osteopontin in order to use this marker as an early and reliable diagnostic tool for the degree of cell transformation in oral squamous carcinoma. Ten histologically healthy oral samples and sixty-four primary oral squamous cell carcinomas specimens were analysed by a single pathologist. Immunohistochemical analysis and Fulgen stain were performed in order to evaluate intensity of expression of osteopontin and fractal dimension. Data obtained were presented as mean and standard deviation and processed for the statistical analysis. Ostepontin expression revealed a statistical significance between groups (P less than 0.001). Fractal dimension in oral squamous cell carcinoma groups vs controls revealed statistically significant differences (P less than 0.001). The fractal dimension value and the osteopontin expression were compared, using two-dimensional scatter. The correlation was relevant in the G3 group. The results demonstrated a correlation between the growths of osteopontin expression and nuclear abnormality measured by fractal dimension. These results support the hypothesis that the level of osteopontin expression might be used as a marker for the evaluation of oral squamous cell carcinoma differentiation. Osteopontin and fractal dimension could support the histological grading to increase the predictability of the diagnosis, choices of treatment procedure and long-term prognosis.

Multimodal-3D imaging based on µMRI and µCT techniques bridges the gap with histology in visualization of the bone regeneration process.

Bone repair/regeneration is usually investigated through X-ray computed microtomography (µCT) supported by histology of extracted samples, to analyse biomaterial structure and new bone formation processes. Magnetic resonance imaging (µMRI) shows a richer tissue contrast than µCT, despite at lower resolution, and could be combined with µCT in the perspective of conducting non-destructive 3D investigations of bone. A pipeline designed to combine µMRI and µCT images of bone samples is here described and applied on samples of extracted human jawbone core following bone graft. We optimized the coregistration procedure between µCT and µMRI images to avoid bias due to the different resolutions and contrasts. Furthermore, we used an Adaptive Multivariate Clustering, grouping homologous voxels in the coregistered images, to visualize different tissue types within a fused 3D metastructure. The tissue grouping matched the 2D histology applied only on 1 slice, thus extending the histology labelling in 3D. Specifically, in all samples, we could separate and map 2 types of regenerated bone, calcified tissue, soft tissues, and/or fat and marrow space. Remarkably, µMRI and µCT alone were not able to separate the 2 types of regenerated bone. Finally, we computed volumes of each tissue in the 3D metastructures, which might be exploited by quantitative simulation. The 3D metastructure obtained through our pipeline represents a first step to bridge the gap between the quality of information obtained from 2D optical microscopy and the 3D mapping of the bone tissue heterogeneity and could allow researchers and clinicians to non-destructively characterize and follow-up bone regeneration.

Cytokine expression profile and blood parameter evaluation of patients undergoing cardiac surgery.

Cardiac surgery is accompanied by an important immune response that is poorly understood. This inflammatory response is caused by several stimuli: surgical trauma, cardiopulmonary bypass apparatus, aortic-cross clamping, reperfusion injury and hypothermia. The aim of the present study is to investigate the cytokine level profile involved in the inflammatory pathway of patients undergoing cardiac surgery. One hundred and two patients undergoing elective cardiac surgery utilizing cardiopulmonary bypass (CPB) apparatus were enrolled in the study. In the hematological and biochemical profiles investigated, we observed a significant increase of WBC and blood glucose concentration and a strong decrease of RBC, HB, HCT and PLT 24 h post-surgery compared to baseline and immediately after surgery groups. Furthermore, we found a modulation of cytokine levels mostly for IL-10 and an increase of IL-6, detected at 6 h post-surgery, IL-8 at 6 and 24 h, and TNFα only at 24 h post-surgery. In conclusion, these findings evidence a time course profile on cytokine levels and a balance between pro- and anti-inflammatory cytokine activation during and after cardiac surgery. In fact, IL-6 and IL-10, a pro- and an anti-inflammatory cytokine, respectively, increased immediately after surgery. The plasma level of TNF-α could be inhibited by the high concentration of IL-10 up to 6 h post-surgery. An IL-10 reduction at baseline level, after 24 h post-surgery, could explain a rise of TNF-α plasma concentration. On the other hand, considering the dual role of IL-6 on inflammation acting both as an activator of inflammatory cascade or an anti-inflammatory agent, the increased IL-6 levels 24 h after surgery could be related to the negative feedback action on TNFα activity.

Cytokine modulation in patients with idiopathic pulmonary fibrosis undergoing treatment with steroids, immunosuppressants, and IFN-γ 1b.

Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease of unknown etiology and pathogenic mechanisms. From an etiopathogenic point of view, alveolar macrophages play a key role in accumulation of fibroblasts and deposition of collagen and extracellular matrix by releasing specific cytokines and inflammatory mediators. IPF seems to be also associated with circulating fibrocytes, which might be involved with an abnormal pulmonary vascular repair and remodeling. Based on its hypothesized pathologic mechanisms, anti-inflammatory, anti-fibrotic and immunosuppressive therapies are often used. For these reasons, Interferon-g (IFN-g) has been used to exploit its activity on macrophages and fibroblasts. The aim of this study was to investigate the response to corticosteroids and/or IFN-g 1b treatments based on pulmonary function tests and on inflammatory cytokine patterns of expression on bronchoalveolar lavage (BAL), at baseline and during and after the therapies. Unlike previous studies, we analyzed a period of therapy longer than 1 year. Our results demonstrated the effectiveness of IFN-γ in a group of IPF patients in whom the treatment was prolonged for over a year. These data suggest a positive role of IFN-γ; treatment in patients in the initial stage of the disease.

Human periodontal ligament stem cells cultured onto cortico-cancellous scaffold drive bone regenerative process.

The purpose of this work was to test, in vitro and in vivo, a new tissue-engineered construct constituted by porcine cortico-cancellous scaffold (Osteobiol Dual Block) (DB) and xeno-free ex vivo culture of human Periodontal Ligament Stem Cells (hPDLSCs). hPDLSCs cultured in xeno-free media formulation preserved the stem cells' morphological features, the expression of stemness and pluripotency markers, and their ability to differentiate into mesenchymal lineage. Transmission electron microscopy analysis suggested that after one week of culture, both noninduced and osteogenic differentiation induced cells joined and grew on DB secreting extracellular matrix (ECM) that in osteogenic induced samples was hierarchically assembled in fibrils. Quantitative RT-PCR (qRT-PCR) showed the upregulation of key genes involved in the bone differentiation pathway in both differentiated and undifferentiated hPDLSCs cultured with DB (hPDLSCs/DB). Functional studies revealed a significant increased response of calcium transients in the presence of DB, both in undifferentiated and differentiated cells stimulated with calcitonin and parathormone, suggesting that the biomaterial could drive the osteogenic differentiation process of hPDLSCs. These data were confirmed by the increase of gene expression of L-type voltage-dependent Ca2+ (VDCCL), subunits α1C and α2D1 in undifferentiated cells in the presence of DB. In vivo implantation of the hPDLSCs/DB living construct in the mouse calvaria evidenced a precocious osteointegration and vascularisation process. Our results suggest consideration of DB as a biocompatible, osteoinductive and osteoconductive biomaterial, making it a promising tool to regulate cell activities in biological environments and for a potential use in the development of new custom-made tissue engineering.

Mandibular third molar displaced in the sublingual space: clinical management and medicolegal considerations.

This paper describes the management of a failed mandibular third molar extraction, resulting in tooth displacement in the sublingual space, the discussion of the diagnosis, surgery and medico-legal considerations. A 28-year-old male patient underwent an unsuccessful attempt of the 4.8 tooth extraction. The clinician lost visual contact after luxation and the patient was not recalled for post-operative follow-up. After 24 hours, a severe trismus started. Ortopantomography and cone beam computer tomography revealed the displacement in the sublingual space. The tooth was removed under general anaesthesia with intraoral approach. The follow-up was uneventful and the paraesthetic area on the tongue did not enlarge after the retrieval. The displaced mandibular third molar is a rare but potentially serious complication of extraction. This event should be avoided with correct diagnosis and surgical technique. Cone beam computed tomography was useful to determine the three-dimensional position of the displaced tooth.

miR-2861 is involved in osteogenic commitment of human periodontal ligament stem cells grown onto 3D scaffold.

miR-2861 endorsing osteoblast differentiation through the overexpression of Runt-related transcription factor 2 (RUNX2) protein has been recently described. In this study we evaluated: the performance of living construct, composed by human Periodontal Ligament Stem Cells (hPDLSCs) and 3D scaffold (EXg), and the behaviour of miR-2861/RUNX2 expression pathway on the osteogenic commitment. Human PDLSCs were seeded with and without EXg scaffold and cultured under basal and osteogenic conditions. Morphological features, adhesiveness and differentiation abilities were analysed using scanning electron and confocal laser scanning microscopy. Time-course of RUNX2, ALP, OPN and miR-2861 were evaluated through RT-PCR analysis. Our results highlighted that the osteogenic differentiation was mostly obvious in the hPDLSCs, grown onto 3D scaffold in presence of osteoinductive medium. Moreover, the overexpression of miR-2861 and RUNX2 in hPDLSCs cultured in presence of EXg under osteogenic and standard conditions was demonstrated. In synthesis, the increased expression of miR-2861/RUNX2 provides new insights regarding miRNA signaling network in the presence of scaffold providing an additional method to evaluate the performance of biomaterial in bone regeneration.

Comparative molecular analysis of bacterial species associated with periodontal disease.

Periodontal disease is an inflammatory disorder affecting the supporting teeth structures, including gingiva, periodontal ligament and alveolar bone, causing loss of connective tissue, reabsorption of alveolar bone and formation of periodontal pockets. The aim of this study is to find a correlation between bacterial growth and periodontal disease. Fifty-seven patients aged between 21 and 65 years, median age 46 years, were enrolled. According to gingival pocket depth, ranging from 3 to 7 mm, patients were divided into two groups: the first (30 patients, 53%) with deep pockets ³ 5 mm and the second (27 patients, 47%) less than 5 mm. The samples taken were processed for microbiological analysis by absolute quantitative real-time Taq-Man technique. Patients affected by periodontal disease were 32 (56%) and patients with gingival bleeding were 35 (61%). This data showed that the presence, the type and the bacterial load in gingival pockets were strongly correlated with gingival depth, periodontal disease and gingival bleeding. Quantitative microbiological analysis is a key point to improve patient compliance, allowing to choose the specific antibiotic treatment. avoiding antibiotic resistance and ensuring the successful outcome of therapy for periodontal disease.

A cytotoxic analysis of a sardinian plant extract cream on human oral primary cell cultures: an in vitro study.

Wound healing agents support the natural healing process, reduce trauma and likelihood of secondary infections and hasten wound closure. The aim of this work was to evaluate the effect of different concentration of a new Sardinian plant cream (RD7) on two human primary cultures: Periodontal Ligament Stem Cells (hPDLSCs) and Gingival Fibroblasts (hGFs) derived from oral tissues in terms of morphological changes, cell proliferation and wound healing properties. RD7, is an interactive dressing containing phytocomplex derived from Sardinian endemic or not, medicinal plant extracts, with an important anti-radical, anti-inflammatory and antiseptic activity finalized to rapidly promote tissue regeneration and the formation of granulation tissue. hPDLSCs and hGFs were seeded at different concentrations (0.5, 1, 2.5 and 5 mg/ml) of RD7. The cell proliferation and viability was evaluated using colorimetric assays (MTT assay) and trypan blue exclusion test. Meanwhile, the morphological cell changes were evaluated by means of optic (OM) and scanning electronic microscopes (SEM). The induction of the migratory properties was evaluated by means of wound healing assay. In vitro results, using hPDLSCs and hGFs, showed a decrease of cell growth starting at 24 h of incubation, at high concentrations (2.5 mg/ml and 5 mg/ml). This cell growth reduction was associated to evident morphological changes, whilst, at low concentrations (0.5 and 1 mg/ml) a typical unchanged morphology of both hPDLSCs and hGFs was shown. Wound healing assay showed a complete wound full closure occurring after 24 h of treatment in samples treated with low concentration of RD7. The results of the present work indicate that low concentrations of RD7 have no cytotoxicity effect, stimulate cell proliferation and contribute to induce the migratory properties in hPDLSCs and hGFs, therefore it could be considered a new product for use in clinical practice.

Pro-inflammatory cytokine release and cell growth inhibition in primary human oral cells after exposure to endodontic sealer.

AIM: To assay the toxicity of the single-methacrylate-based sealer urethane dimethacrylate (UDMA) (EndoRez) in terms of cell growth and pro-inflammatory cytokines release, in expanded ex vivo human dental pulp stem cells (hDPSCs), human periodontal ligament stem cells (hPDLSCs), human gingival fibroblasts (hGFs) and human osteoblasts (hOSTs). METHODOLOGY: Dental pulp and periodontal ligament stem cells, osteoblasts and fibroblasts were derived from five young donors. After in vitro isolation, hDPSCs, hPDLSCs, hGFs and hOSTs were seeded to resin-based sealers for 24, 48, 72 h up to 1 week. The morphological features and the cell growth and the release of pro-inflammatory interleukin (IL)6, IL8, IL12 and tumour necrosis factor (TNF) α were analysed. Differences in cell growth and in interleukin secretion were analysed for statistical significance with two-way anova tests for multiple comparisons. RESULTS: Exposure to endodontic sealer based on UDMA resulted in a 50% decrease in survival oral cells at 24 h of incubation. No evident morphological changes were present in cell cultures examined. After 48 h, 72 h and 1-week culture time, a progressive cell growth was evident. A significant up-regulation of IL6, IL8, IL12 and TNFα cytokines in cells in contact with the dental sealer compared to the control was observed. CONCLUSION: In vitro, EndoRez interacted with primary human hDPSCs, hPDLSCs, hGFs and hOSTs causing damage to biological system evidenced through cell growth inhibition and up-regulation of IL6, IL8, IL12 and TNFα proinflammatory mediators.

Use of Oral Chroma™ in the assessment of volatile sulfur compounds in patients with fixed protheses.

Prosthetic rehabilitation improves the patient's quality of life and oral health. The purpose of the present study was to assess the production of volatile sulfur compounds (VSCs) using Oral Chroma™ in patients wearing provisional and permanent fixed prosthesis, who were treated or not, with supportive non-surgical periodontal therapy. A total of 10 healthy patients not affected by periodontal disease and who needed the restoration of at least two edentulous single sites were included in the present study. Registrations of VSCs were carried out with a Gas Chromatograph OralChroma™ (Oral Chroma™, Abimedical, Abilit Corp., Osaka, Japan) one month after placement of the provisional restoration (group 1) and one month after placement of the final restoration (group 3). After each measurement, professional oral hygiene was carried out both on patients with provisional (group 2) and permanent prostheses (group 4) and VSC values were registered. The results showed that there were no statistical significant differences in the VSC quantity between groups with temporary or permanent prostheses. Meanwhile, statistically significant differences were found in VCS values between groups before and after the professional health care session (p less than 0.05). Also it was observed that dimethyl sulphide (CH3)2S was present in all the study groups. The present preliminary study suggests that OralChroma™ produce a comprehensive assessment of VSC in the clinical diagnosis of halitosis and that professional oral hygiene seems to influence VSC production. However, further clinical long-term studies with a larger sample size are necessary for a better understanding of halitosis manifestation in patients wearing provisional and permanent fixed prosthesis.

Copper-zinc superoxide dismutase activity in dental pulp after dental preparation.

The superoxide dismutases (SODs) are the major enzymatic defence mechanism against toxic reactive oxygen species generated during normal oxidative metabolism and during the respiratory burst associated with inflammation. To further clarify the potential role of copper-zinc (Cu/Zn)-SOD during inflammation of pulp tissue in humans, the aim was to determine whether significant changes in Cu/Zn-SOD activity occur in healthy dental pulp after dental preparation. The condition of the pulp was assessed using clinical and radiographic evaluation. Thirty systemically healthy patients were the source of the pulp tissue, which was collected by longitudinally grooving and splitting teeth that were matched between the control dental pulp and the prepared tooth (test) dental pulp. Cu/Zn-SOD activity was determined through spectrophotometric methods, with Mann-Whitney tests used to assess the significance of the differences between the groups. The Cu/Zn-SOD activity was 168.2+/-46.4 mU.mg−1 total protein (range: 96-212 mU.mg−1) in the control group, and 328.2+/-84.2 mU.mg−1 total protein (range: 280-420 mU.mg−1) in the test group. The difference between the groups was statistically significant, at P <0.001. These results demonstrate a potential role for Cu/Zn-SOD during dental pulp inflammation in humans after dental preparation.

Two-step impression/ injection, an alternative putty/ wash impression technique: case report.

We here describe a new technique for making a definitive impression that we refer to as the two-step impression/injection technique. This technique initially follows the classical one-step putty/ light-body impression technique with the polymerization of the putty and the light-body compound. This is then followed by the second step: injection of extra-light-body compound into the preparation through a hole in the metal stock tray. The aim of this additional step is to control the wash bulk and minimize the changes that can produce unfavorable impression results. This new two-step impression/injection technique allows displacement of soft tissues, such as the tongue, during the first seating of the putty and wash materials, while in the second step, the extra-light-body compound records all of the finer details without being compressed.

Influence of titanium laser surface geometry on proliferation and on morphological features of human mandibular primary osteoblasts.

The aim of this study is to assess in vitro the proliferation and the morphological changes of primary osteoblast-like cells (HOst) seeded on titanium dish grade 4 and 5 with different roughness and different titanium grade: machined (M), sandblasted (SBT), laser-treated with pitches of 20-microm diameter and 30-microm interpore distance. The titanium disks were divided into two groups: group A (titanium grade 4) and Group B (titanium Grade 5), respectively. Proliferation rate of attached cells was evaluated at different time (24, 48, 72 h and 1 week) by the quantitative colorimetric MTT assay. Our results showed a cell growth decrease evident in M titanium surfaces in both Groups A and B, while the cells seeded on the STB and laser disks displayed an increase of cells growth, more evident in laser titanium surfaces in groups A and B. Morphological changes of the biocomplex cells/titanium was assessed by light, scanning and confocal microscopy. In fact, the microscopic analysis helped to clarify the behavior of the cells in contact with the titanium surfaces, in particular the M surface induced significant morphological changes, which were less evident in the SBT surfaces. Laser-engineered porous titanium surfaces promoted viability and proliferation of the osteoblasts. In particular, hemispherical porosity of 20 microm could be responsible for the higher HOst activation, in terms of cells proliferation, adhesion and morphological features.

Morphological analysis and interleukin release in human gingival fibroblasts seeded on different denture base acrylic resins.

The development of different types of materials with application in practice dentistry is an area of intense growth and research due to its importance in oral health. Among the diverse materials currently used in restoration or in dentures, the acrylic based resins have been widely employed. The release of toxic components and the changes on their physical and mechanical properties actually represent a goal of intensive research. In vivo analysis showed that the surface roughness of the acrylic resin represents a factor that could stimulate bacteria colonization and soft tissue inflammation. For this purpose, in this work, we have analyzed the cell response to acrylic based resins Ivoclar, Tokuso and Coldpack in basal conditions, unpolished, and after the polished procedure performed to reduce the surface roughness. Our in vitro results using human gingival fibroblasts (HGFs) showed a decrease of cell growth, evaluated by MTT assay starting at 24 h of incubation, in samples seeded on resins in basal conditions and after the polished procedure. This cell growth reduction was associated to evident morphological changes in unpolished materials. After 24 h of culture in presence of polished and unpolished resins a spontaneous release was present of pro-inflammatory cytokines such as interleukin-6 (IL-6) and -8 (IL-8), which was higher in unpolished resins, indicating that the polished procedure, minimizing the cytotoxicity process, could contribute to reduce the gingival inflammation processes.

Bone regeneration in sinus augmentation procedures with calcium sulphate. Microstructure and microanalytical investigations.

BACKGROUND: The aim of this study was a histological and ultrastructural evaluation of the bone formed in human sinus augmentation procedures with calcium sulphate (CaS). METHODS: Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were used to evaluate the relationship between CaS and newly-formed bone, while birefringence was used to evaluate the bone structure around the CaS particles by polarized light microscopy. Unstained sections were studied with an Axiovert 200 M using the fluorescence in reflected UV light to evaluate the interface between CaS and newly-formed bone. Twenty specimens retrieved from the sinus after a healing period of six months were studied. RESULTS: EDS analysis of six specimens showed that little sulphur remained and residual particles appeared to have transformed to calcium phosphate. Under polarized light a few biomaterial remnants were present in some areas and covered by mature bone. The relationship between residual particles and bone due to the different photon emission under UV light stimulation was observed under fluorescence microscopy. CONCLUSIONS: The present results confirm the high biocompatibility and rapid resorption rate of CaS. The mechanism of transformation of CaS to calcium phosphate, already demonstrated in animal studies, has been confirmed in the present human study.

Overexpression of interleukin-6 and -8, cell growth inhibition and morphological changes in 2-hydroxyethyl methacrylate-treated human dental pulp mesenchymal stem cells.

AIM: To evaluate morphological features, cell growth and interleukin-6 (IL-6) and interleukin-8 (IL-8) secretion in expanded ex vivo human dental pulp mesenchymal stem cells (DP-MSCs) after exposure to 2-hydroxyethyl methacrylate (HEMA). METHODOLOGY: Dental pulp mesenchymal stem cells were derived from the dental pulps of 10 young donors. After in vitro isolation, DP-MSCs were treated with 3 and 5 mmol L(-1) HEMA, and after 24, 48 and 72 h of incubation, their morphological features, cell growth, IL-6 and IL-8 secretion were analysed. Differences in the cell growth and in the interleukin secretion were analysed for statistical significance with two-way anova tests and the Holm-Sidak method for multiple comparisons. RESULTS: Dental pulp mesenchymal stem cells revealed a decrease in cell growth with both treatments (P < 0.05), more evident at 5 mmol L(-1) . Microscopic analysis displayed extensive cytotoxic effects in treated cells, which lost their fibroblastoid features and became retracted, even roundish, with a large number of granules. An up-regulation of IL-6 and IL-8 in treated cells cytokines was evident (P < 0.05). CONCLUSIONS: 2-Hydroxyethyl methacrylate exhibited cytotoxicity, inhibited cell growth and induced morphological changes in cultured DP-MSCs. Moreover, in treated samples, an up-regulation of soluble mediators of inflammation such as IL-6 and IL-8 cytokines was found. The direct application of HEMA potentially induces an inflammation process that could be the starting point for toxic response and cell damage in DP-MSCs.