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.

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.

Dental Pulp Stem Cells Bioadhesivity: Evaluation on Mineral-Trioxide-Aggregate

Stem cells are undifferentiated cells that have the capacity to self-renew. They have been discovered in many adult tissues, including teeth. Dental Pulp Mesenchymal Stem Cells (DP-MSCs) are involved in dental repair by activation of growth factors, released after caries and have the ability to regenerate a dentin-pulp-like complex. The molecular/cellular research gives the possibility to grow new tissues and biological structures for clinical applications, providing cells for therapies including cell transplantation and tissue engineering. In this study DP-MSCs were derived from dental pulp of 10 donors. To evaluate material toxicity, after in vitro isolation, the cells were seeded on mineral trioxide aggregate (MTA). Initial light microscopy investigation of cells revealed no signs of cell death due to toxicity or infection, on the contrary the scaffolds supplied an excellent support for cell structures, the cells proliferated and adhered to substrate. Similar observation was seen in scanning electron microscopy, in particular the cells had proliferated and spread, covering a considerable part of the surface of the biomaterials investigated, with an elaborate form of attachment, in fact, the cells formed a continuous layer on the upper surface of the MTA. In conclusion, the aim of this study is to demonstrate that DP-MSCs combined with MTA could be a potential source for regenerative medicine, encouraging further study to evaluate the new dentin formation.

NOS Evaluations in Human Dental Pulp-Capping with MTA and Calcium-Hydroxide

The aim of this study is to compare mineral trioxide aggregate (MTA) with calcium hydroxide when used as pulp-capping material in human teeth. 40 teeth were divided into groups based on clinical diagnosis: healthy and hyperaemic. The teeth were pulp capped with MTA and calcium hydroxide. We localized the eNOS and iNOS by immunohistochemistry, tested their mRNA expression by RT-PCR and protein levels by western blots. The evaluation of the samples was based on the cell inflammatory response and on the pulp tissue organization. In particular, evaluation of eNOS and iNOS differences between the various groups and the cellular evolution after the first 7 days from the treatment, and at a distance of 28 days. Our results suggest that there are differences in localization and expression between eNOS and iNOS in dental pulp. Our study has helped us to better understand the effects that calcium hydroxide and MTA have on pulp tissue.

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.

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.

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.

Pulp-Dissolving Ability of Several Endodontic Irrigants: A Spectro-Photometry Evaluation

The aim of this study is to test the dissolving action of different concentrations of NaOCl (0.5%, 2.5% and 5%) and EDTA 17% on bovine pulp tissue, testing solutions at three different times (1, 5, 10 minutes). 100 mg. of dental pulp placed into a becher with 20 ml of solution was evaluated using a spectrophotometer. A solution of NaOCl 5% showed the highest solubility value. Samples treated with 2.5% NaOCl showed solubility values of 0.98 in one minute, 29.1 in five minutes and 57 in ten minutes. Groups treated with NaOCl 0.5% showed small dissolving modifications. 17% EDTA showed the lowest values of solubility. 5% NaOCl solution showed highest pulp dissolving ability, even a 2.5% solution showed high dissolving ability but in longer times.

Adult Mesenchymal Stem Cells in Dental Research: A New Approach for Tissue Engineering

Many adult tissues contain a population of stem cells that have the ability to regenerate after trauma, disease or aging. Recently, there has been great interest in mesenchymal stem cells and their roles in maintaining the physiological structure of tissues. The studies on stem cells are thought to be very important and, in fact, it has been shown that this cell population can be expanded ex vivo to regenerate tissues not only of the mesenchymal lineage, such as intervertebral disc cartilage, bone and tooth-associated tissues, but also other types of tissues. Several studies have focused on the identification of odontogenic progenitors from oral tissues, and it has been shown that the mesenchymal stem cells obtained from periodontal ligament and dental pulp could have similar morphological and phenotypical features of the bone marrow mesenchymal cells. In fact a population of homogeneous human mesenchymal stem cells derived from periodontal ligament and dental pulp, and proliferating in culture with a well-spread morphology, can be recovered and characterized. Since these cells are considered as candidates for regenerative medicine, the knowledge of the cell differentiation mechanisms is imperative for the development of predictable techniques in implant dentistry, oral surgery and maxillo-facial reconstruction. Thus, future research efforts might be focused on the potential use of this cell population in tissue engineering. Further studies will be carried out to elucidate the molecular mechanisms involved in their maintenance and differentiation in vitro and in vivo.

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.

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.

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.

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.

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.

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.

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.

Toll-like Receptor 4 Expression, Interleukin-6, -8 and Ccl-20 Release, and NF-KB Translocation in Human Periodontal Ligament Mesenchymal Stem Cells Stimulated with LPS-P. Gingivalis

Periodontal diseases, the major public health problem of the oral cavity, are clinically characterized by inflammation of the periodontal connective tissue that ultimately induces the destruction of periodontal tissue and the loss of alveolar bone. In chronic periodontitis, as well as aggressive periodontitis, the anaerobic gram-negative bacterium Porphyromonas gingivalis (P. gingivalis) is implicated. The pathogenicity of P. gingivalis is exerted by a wide variety of factors, including lipopolysaccharides (LPSs). LPSs activate the innate immune response during Gram-negative bacterial infections through the Toll-like receptor 4 (TLR-4)/myeloid differentiation protein 2 (MD-2) complex. In this study, the expression of TLR-4, the cell growth, the cytokine release, and the nuclear factor-KB (NF-kB) transcription factor expression in response to LPS- P.Gingivalis (LPS-G) were examined in Human Periodontal Ligament Mesenchymal Stem Cells (PDL-MSCs). The results obtained demonstrate that, in basal conditions, human PDL-MSCs express high levels of TLR-4. In inflammatory conditions mimicked by LPS-G challenge, the MTT assay carried out at different treatment times demonstrated the decrease of the cell growth. Moreover, the recognition of P. gingivalis components by TLR-4 culminated with the activation of secretion of inflammatory mediators such as: IL-6, IL-8 and CCL-20, and with the up-regulation of NF-kB, which was translocated into the nucleus. Our data intended to specify that TLR-4 expressed by PDL-MSCs is functional and plays a key role in inflammation.

Soft-Tissue Healing and Impression Technique in Implant Dentistry: A Case Report

The present clinical report describes a technique for aesthetic restoration of single dental implants in the anterior area. One objective of implant therapy in anterior areas is the achievement of an aesthetic result, which is highly dependent on the condition of the peri-implant soft tissue. A 22-year-old woman presented with right maxillary lateral incisor agenesis. An implant was placed, and a transfer impression technique carried out. The model was used to construct the custom abutment, provisional crown, and metal substructure. The metal substructure was covered with a waxed collar with the same emergence profile as the provisional restoration. The abutment and the provisional crown were placed, and after soft-tissue healing, an impression was taken using the waxed metal framework as coping. This final impression also registered and transferred the architecture of the soft peri-implant tissues. This clinical report describes an impression technique that accurately duplicates the peri-implant tissue profile. The final prosthesis is therefore shaped according to the interim prosthesis, for ideal contour and soft-tissue position. This technical procedure requires minimal chair time and is cost effective, as fewer components are used during the treatment.

Vascular endothelial growth factor enhances in vitro proliferation and osteogenic differentiation of human dental pulp stem cells

Mesenchymal stem cells (MSC), isolated from dental tissues, are largely studied for future application in regenerative dentistry. In this study, we used MSC obtained from human dental pulp (DPSC) of normal impacted third molars that, when cultured in lineage-specific inducing media, differentiate into osteoblasts and adipocytes (evaluated by Alizarin Red S and Red Oil O stainings, respectively), thus showing a multipotency. We confirmed that DPSC, grown under undifferentiating conditions, are negative for hematopoietic (CD45, CD31, CD34, CD144) and positive for mesenchymal (CD29, CD90, CD105, CD166, CD146, STRO-1) markers, that underwent down-regulation when cells were grown in osteogenic medium for 3 weeks. In this condition, they also exhibit an increase in the expression of osteogenic markers (RUNX-2, alkaline phosphatase) and extracellular calcium deposition, whereas the expression of receptors (VEGFR-1 and -2) for vascular endothelial growth factors (VEGF) and related VEGF binding proteins was similar to that found in undifferentiated DPSC. Exposure of DPSC growing under undifferentiating or osteogenic conditions to VEGF-A165 peptide (10-40 ng/ml) for 8 days dose- and time-dependently increased the number of proliferating cells without inducing differentiation towards endothelial lineage, as evaluated by the lack of expression of specific markers (CD31, CD34, CD144). Additionally, exposure of DPSC cultured in osteogenic medium to VEGF-A165 for a similar period enhanced cell differentiation towards osteoblasts as evaluated after 14 and 21 days by Alizarin Red S staining and alkaline phosphatase activity quantification. These findings may have clinical implications possibly facilitating tissue repair and remodeling.

Functional assay, expression of growth factors and proteins modulating bone-arrangement in human osteoblasts seeded on an anorganic bovine bone biomaterial

The basic aspects of bone tissue engineering include chemical composition and geometry of the scaffold design, because it is very important to improve not only cell attachment and growth but especially osteodifferentiation, bone tissue formation, and vascularization. Geistlich Bio-Oss (GBO) is a xenograft consisting of deproteinized, sterilized bovine bone, chemically and physically identical to the mineral phase of human bone. In this study, we investigated the growth behaviour and the ability to form focal adhesions on the substrate, using vinculin, a cytoskeletal protein, as a marker. Moreover, the expression of bone specific proteins and growth factors such as type I collagen, osteopontin, bone sialoprotein, bone morphogenetic protein-2 (BMP-2), BMP-7 and de novo synthesis of osteocalcin in normal human osteoblasts (NHOst) seeded on xenogenic GBO were evaluated. Our observations suggest that after four weeks of culture in differentiation medium, the NHOst showed a high affinity for the three dimensional biomaterial; in fact, cellular proliferation, migration and colonization were clearly evident. The osteogenic differentiation process, as demonstrated by morphological, histochemical, energy dispersive X-ray microanalysis and biochemical analysis was mostly obvious in the NHOst grown on three-dimensional inorganic bovine bone biomaterial. Functional studies displayed a clear and significant response to calcitonin when the cells were differentiated. In addition, the presence of the biomaterial improved the response, suggesting that it could drive the differentiation of these cells towards a more differentiated osteogenic phenotype. These results encourage us to consider GBO an adequate biocompatible three-dimensional biomaterial, indicating its potential use for the development of tissue-engineering techniques.

The cytotoxic effects of resin-based sealers on dental pulp stem cells

AIM

To evaluate the effect of four current resin-based adhesives on expanded ex vivo human dental pulp mesenchymal stem cells (DP-MSCs).

METHODOLOGY

Dental pulp mesenchymal stem cells were derived from dental pulps of ten donors. After in vitro isolation, dental pulp stem cells were analysed using flow cytometry. The immunophenotype of DP-MSCs disclosed the homogeneous expression of the mesenchymal-related antigens CD29, CD44, CD73, CD90, CD105, CD166. DP-MSCs were exposed to four different commercially available bonding systems (CMF Bond, Prime&Bond NT, Clearfil S(3) Bond, XP Bond), and after 24, 48 and 72 h of incubation the morphological features and the cell growth were analysed. Moreover, the cell viability was evaluated at the same times by MTT assay. Data were statistically analysed using a two-way anova and Holm-Sidak method (alpha set at 0.05).

RESULTS

Significant differences were observed between the four groups when comparing DP-MSCs appearance. DP-MSCs survived and proliferated without inhibition in the presence of CMF Bond adhesive. On the contrary, microscopic evaluation of the other three groups revealed extensive cytotoxic effects from the dentine bonding agents. The MTT assay revealed no statistically significant differences in cell viability after 72 h between the control group and CMF Bond group. All the other experimental groups had statistically lower optical density values.

CONCLUSIONS

CMF Bond adhesive allowed human dental pulp stem cells to survive and proliferate. All of the other dentine bonding agents had extensive cytotoxic effects.

The Influence of Luting Systems on the Microtensile Bond Strength of Dentin to Indirect Resin-based Composite and Ceramic Restorations

Compared to self-etch and self-adhesive luting systems, the two etch-and-rinse luting agents evaluated in the current study provided more reliable bonding when used to bond indirect resin-based composite restorations to sound dentin. On the contrary, the self-adhesive luting system showed the highest mean bond strength for the cementation of glass ceramic restorations.

Prescriptions of NSAIDs to patients undergoing third molar surgery : an observational, prospective, multicentre survey

BACKGROUND AND OBJECTIVES

Surgical extraction of an impacted third molar is generally followed by acute post-operative pain that has been shown to be primarily inflammatory. Thus, use of NSAIDs in this context is appropriate and has been shown to be effective. Several drugs are employed for this purpose, but no information exists on the reasons why preference is given to one rather than another. The principal objective of this study was to evaluate the pattern of administration of NSAIDs in patients undergoing surgery for impacted third molar extraction. The study also aimed to collect information on the efficacy, onset and duration of the analgesic effect of routinely prescribed NSAIDs and to assess the duration of treatment with these drugs and their tolerability.

METHODS

This was an observational, multicentre, prospective survey. A total of 616 patients (38% male and 62% female) from the Italian Stomatology Clinics of the Universities of Bologna, Brescia, Cagliari, Chieti, Pavia, Pisa, Siena and Varese and from the Department of Oral and Maxillo-Facial Surgery of Semmelweis University, Budapest, were eligible for the study. Patients were evaluated over the 7 days following surgical extraction. NSAIDs were prescribed according to the normal prescribing habits of the centre and physician involved. The main outcomes of interest in the survey were the efficacy, onset and duration of analgesic effect, duration of therapy, and tolerability of the NSAIDs prescribed.

RESULTS

Nimesulide was the most prescribed NSAID (68%), followed by diclofenac, ketoprofen and ibuprofen. Because of the low proportion of patients receiving other NSAIDs, these patients were considered a single treatment group for evaluation purposes. Nimesulide, especially when given before patients started experiencing pain after surgery, was more effective than other NSAIDs in reducing the severity of pain on the day of surgery, in delaying the time to maximum intensity of pain, in providing complete pain relief and in prolonging the duration of analgesic effect on the day of surgery. These results are consistent with the known anti-inflammatory and analgesic actions of nimesulide and with the important role of inflammation in the onset of pain after this type of surgery.

CONCLUSION

These results confirm nimesulide as an effective reference drug for the treatment of post-operative dental pain and show that it has a positive benefit/risk profile in this setting.

Regenerative potential of human periodontal ligament derived stem cells on three-dimensional biomaterials: a morphological report

Recent studies have shown that mesenchymal stem cells obtained from periodontal ligament (PDL-MSCs) are multipotent cells that have similar features of the bone marrow and dental pulp MSCs and are capable of proliferating and producing different types of tissue such as bone and tooth associated-tissues. Human PDL-MSCs expanded ex vivo were induced to osteogenesis, seeded in three-dimensional biocompatible scaffolds (fibrin sponge, bovine-derived substitutes) and examined using light, scanning and transmission electron microscopy. Morphological observations showed extensive growth of cellular biomass partially covering the scaffolds after 4 weeks of incubation in mineralization medium. These findings indicate that periodontal ligament can be an easily and efficient autologous source of stem cells with a high expansion capacity and ability to differentiate in osteogenic cells that can colonize and grow connected to bio-compatible scaffold. It can be suggested that the use of PDL-MSCs for generating graft biomaterials is advantageous for bone tissue engineering in regenerative dentistry.

Changes in matrix extracellular phosphoglycoprotein expression before and during in vitro osteogenic differentiation of human dental papilla mesenchymal cells

The purpose of this study is to characterise the expression of matrix extracellular phosphoglycoprotein (MEPE) in cultured mesenchymal cells isolated from human dental papilla (PaMCs) of impacted third molars either before or during differentiation of these cells into osteo/odontoblasts. PaMCs, like mesenchymal cells deriving from human dental pulp (DPMCs), resulted positive for a number of mesenchymal markers including CD146 and STRO-1. During the first week in culture they showed a faster proliferation rate than DPMCs, coupled to an earlier down-regulation of MEPE. Also when the cells were further cultured in osteogenic medium (containing beta-glycerophosphate, ascorbic acid and dexamethasone) for 40 days, MEPE down-regulation coupled to an increased expression of osteogenic markers, such as osteocalcin and alkaline phosphatase, occurred earlier in PaMCs than in DPMCs. Thus, our data, indicating that also in PaMCs MEPE expression is higher when cells proliferate, whereas it is downregulated as cells differentiated, are in favour of a role of MEPE as an early regulator of odontogenic differentiation. We also confirm the superior proliferative potential of PaMCs in comparison with DPMCs, coupled to a more rapid induction of osteogenic differentiation. Therefore, these cells represent an optimal source to be conveniently used for dental tissue engineering and tooth regeneration.

Bone microstructure evaluation near unloaded dental implants combining confocal scanning laser microscopy, circularly polarized light microscopy, and SEM backscattered electrons imaging

The aim of this report is to present a new investigative approach to implant dentistry based on the correlation of qualitative and quantitative data reported on the same figure by overlapping different images collected on the specimen with different investigative systems. Six unloaded titanium dental implants retrieved with peri-implant bone from the mandible of 2 patients after a 6 month period were used in this study. Samples of the peri-implant tissues embedded in resin were imaged by scanning electron microscopy using backscattered electrons signal (SEM BSE), confocal scanning laser microscopy (CSLM) and circularly polarized light microscopy (CPLM). The SEM BSE images were used to identify the different levels of mineral density. The CSLM images provided all the information on cells and bone marrow spaces. The CPLM images gave the collagen fibre orientation. To overlap the images we used a program introduced by Alan Boyde, based on a linear transformation matrix which projects one system onto the other. The total bone area investigated was of 695x10(3) pixels. The low mineral density index was 40.1, with an extension area of 344x10(3) +/- 23x10(3) pixels (mean +/- SD) while the high mineral density index was 54.8 with an extension area of 317x10(3) +/- 22x10(3) pixels (mean +/- SD). Transverse collagen fibers showed an extension area of 201x10(3) +/- 25x10(2) pixels (mean +/- SD) (28.9%), while the area for longitudinal orientation was 282x10(3) +/- 19x10(2) pixels (mean +/- SD) (40.6%). The marrow spaces showed an extension of 113x10(3) +/- 24x10(2) pixels (mean +/- SD) (16.3%). This method demonstrated that bone near unloaded implants showed almost the same extension for longitudinal and transverse collagen fibre with a predominantly low mineral density index closest to the implant surface.

Modification of condyle anatomy following a monolateral bite rise: a histological study in rat

The aim of this study is to evaluate the histologic modifications of rat articular capsules, after compression and strain. Fifty adults Sprague Dawley rats were used in this study. The rats were divided into 3 groups: a dysfunction group, treatment group and a Control group. In the rats in the first two groups an occlusion hump, made of composite and less than 0.5 mm high, was applied to the upper right molar. The rats were anesthetized with an intraperitoneal injection of benzodiazepine (0.5-1 mg for 100 g. of body weight). The composite used consisted of a hollow, plastic cylinder 0.5 mm high, spread over the whole occlusal surface of the right upper molar. The dysfunction group therapy wore the occlusion hump for a week, at the end of which the animals in this group were killed and their temporomandibular joint removed. In the treatment group a second occlusion hump was applied to the left upper molar, in order to obtain a distraction of the previously compressed temporomandibular joint. The rats of the second group wore the second occlusion hump for one week. The rats were then killed with an intraperitoneal injection of Tanax, and the block sections, containing the temporo-mandibolar joint, were retrieved with a diamond disk, and surrounding tissues were washed in saline solution and immediately fixed in 4 percent formalin for 4 days. In the control group, no treatment was applied. In the first group, bone resorption was observed in the left temporomandibular joint; no osteoclast were, however, present. No other tissue alterations were present. Newly formed bone undergoing remodelling was intensely stained with acid fuchsin. In the second and third groups, no bone remodelling areas were observed. In conclusion, the compression of the temporomandibular joint determined a remodelling of the bone structure of the condyle.

The performance of human periodontal ligament mesenchymal stem cells on xenogenic biomaterials

Mesenchymal stem cells from periodontal ligament (PDL-MSCs) hold great promise for bone regeneration. Most studies regarding the osteogenic differentiation of stem cells from periodontal tissue suggest that PDL cells may have many osteoblast-like properties, including the ability to form calcified nodules in vitro. This study investigated the morphological and histochemistry aspects of human PDL-MSCs, induced for osteogenic differentiation and seeded on a xenogenic porcine bone substitute in vitro, at different times of incubation. This biomaterial seems physically identical to human bone, and it has been reported to be osteoconductive. Our results indicated that the cells had a high affinity for the three-dimensional biomaterials; in fact, cellular proliferation and colonization was evident, and after 21 days the adherent cells started to detach themselves from the substrate, and at 30 days of incubation in differentiation medium, the cells completely lost the adhesion to the Petri's disk, englobing all bioparticles. In conclusion, the in vitro behaviour of PDL-MSCs and their relationship with three-dimensional scaffold biomaterials encourage in vivo investigations for their use in dental tissue regeneration.

Electromyographic activity of masticatory, neck and trunk muscles of subjects with different skeletal facial morphology ? a cross-sectional evaluation

The electromyographic pattern activity of masticatory, neck and trunk muscles was assessed using surface electromyography (sEMG) in 60 Caucasian adult females (20 subjects in skeletal class I, 20 subjects in skeletal class II and 20 subjects in skeletal class III), classified on the base of their skeletal class (ANB angle), corrected on the base of maxillary and mandibular rotations. The sEMG activity was recorded at mandibular rest position and during maximal voluntary clenching. At mandibular rest position, the sEMG activities of masseter and anterior temporal muscles were significantly higher in class III subjects than in class I and class II subjects, that showed no significant difference between them. Then, the sEMG activities of posterior cervicals and upper trapezius were significantly higher in skeletal class III subjects than in the other two groups. During maximal voluntary clenching, no significant difference was observed in the sEMG activity of masticatory muscles among the three considered groups. However, the sEMG activities of posterior cervicals and upper trapezius were significantly higher in skeletal class III subjects than in the other two groups, which showed no significant difference between them. In conclusion, the skeletal class seems to affect the sEMG pattern activity of masticatory, neck and trunk muscles.

Morphological and cytofluorimetric analysis of adult mesenchymal stem cells expanded ex vivo from periodontal ligament

Many adult tissues contain a population of stem cells that have the ability of regeneration after trauma, disease or aging. Recently, there has been great interest in mesenchymal stem cells and their roles in maintaining the physiological structure of tissues, and their studies have been considered very important and intriguing, after having shown that this cell population can be expanded ex vivo to regenerate tissues not only of the mesenchymal lineage, such as intervertebral disc cartilage, bone, tooth-associated tissue, cardiomyocytes, but also to differentiate into cells derived from other embryonic layers, including neurons. Currently, different efforts have been focused on the identification of odontogenic progenitors from oral tissues. In this study we isolated and characterized a population of homogeneous human mesenchymal stem cells proliferating in culture with an attached well-spread morphology derived from periodontal ligament, a tissue of ectomesenchymal origin, with the ability to form a specialized joint between alveolar bone and tooth. The adherent cells were harvested and expanded ex vivo under specific conditions and analysed by FACScan flow cytometer and morphological analysis was carried out by light, scanning and transmission electron microscopy. Our results displayed highly evident cells with a fibroblast-like morphology and a secretory apparatus, probably indicating that the enhanced function of the secretory apparatus of the mesenchymal stem cells may be associated with the secretion of molecules that are required to survive and proliferate. Moreover, the presence in periodontal ligament of CD90, CD29, CD44,CD166, CD 105, CD13 positive cells, antigens that are also identified as stromal precursors of the bone marrow, indicate that the periodontal ligament may turn out to be a new efficient source of the cells with intrinsic capacity to self-renewal, high ability to proliferate and differentiate, that can be utilized for a new approach to regenerative medicine and tissue engineering.

Copper-zinc superoxide dismutase activity in healthy and inflamed human dental pulp

AIM

To examine copper-zinc superoxide dismutase (Cu, Zn-SOD) activity in clinically healthy and symptomatic human dental pulps.

METHODOLOGY

Twenty-five systemically healthy patients, 14 females and 11 males (age: 13.1-34.6 years; mean: 21.7 +/- 6.3), were the source of the pulp tissue. The condition of the pulps was assessed using clinical and radiographic evaluation. The pulp tissue was collected by longitudinally grooving and splitting the teeth (if extracted) or during endodontic treatment, and were age- and sex-matched between the healthy and the irreversible symptomatic pulpitis tissue groups. Cu, Zn-SOD activity was determined through spectrophotometric methods and a Mann-Whitney test assessed the significance of differences between the groups.

RESULTS

The enzyme activities were 144.8 +/- 42.2 and 68.1 +/- 25.0 U mg(-1) in the healthy and irreversible symptomatic pulp tissue, respectively. The difference between the groups was statistically significant (P < 0.001).

CONCLUSIONS

These results demonstrate a potential role for Cu, Zn-SOD during dental pulp inflammation in humans.

Risk/Prevention Indicators for the Prevalence of Dental Caries in Schoolchildren: Results from the Italian OHSAR Survey

The Italian Oral Health of Schoolchildren of the Abruzzo Region (OHSAR) Survey was designed to assess indicators associated with the prevalence of caries in both the primary and permanent dentitions in the same schoolchildren, and it comprised a representative sample of 5,938 7-, 9- and 11-year-old schoolchildren from three provinces within the region of Abruzzo, Italy, a low fluoride concentration area. Gender, age, geographic location, socioeconomic level, dietary and oral hygiene habits, and the use of F supplements were all considered as indicators. The subsequent multivariate analyses showed that the socioeconomic level, snack consumption frequency, consumption of sweets and the use of F supplements were mostly associated with caries prevalence in both dentitions. Other indicators, such as gender, age, geographic location, between-meal snack consumption frequency, consumption of sweet drinks, toothbrushing frequency and onset of regular toothbrushing habits also showed some significant associations with dental caries across the age groups and/or dentitions. Of interest, the consumption of commercial bottled mineral water was also seen to be a preventive indicator for dental caries of the primary dentition, particularly in the 7-year-old group. The consumption of sweet snacks, use of interdental floss and kind of toothbrush mainly used (manual or electric) did not show any relevant association with the outcomes. The strong effect of the geographic location, socioeconomical level and the preventive effects of commercial bottled mineral water are worth further investigation.

Residual and inflammatory radicular cysts. Clinical and pathological aspects of 2 cases

Inflammatory odontogenic cysts include radicular cysts and its etiological variance, residual cysts. Among these lesions, the radicular cyst is the most frequent. It is caused by the growth of remnants of Malassez cells involved in the development of the dental organ. Clinically, radicular cysts are difficult to diagnose. Histologic diagnosis is of primary importance in order to definitely discriminate the different kinds of periapical lesions. In this paper, the clinical, radiographic, etio-physio-pathological and microscopic features of these pathological formations are described. A case of a large radicular cyst and a case of residual cyst are reported and the surgical treatment and histologic differential diagnosis are presented.

[Marginal adaptation after cementing of gold inlays cast by an experimental procedure. SEM analysis]

AIM

Marginal adaptation is one of the most important factors in dental reconstructions. The aim of the present work was to evaluate with in vivo and in vitro studies the marginal precision and the microstructure of the gold cast inlays.

METHODS

For the in vivo analysis 10 patients were selected, while for the in vitro study 10 extracted teeth were used. The impressions were made by polyvinylsiloxane while the master cast was made by gypsum type IV. The inlays were cast in gold (JRVT Jensen) using an experimental procedure. After cementing, the margins of each inlay was burnished. To evaluate the marginal discrepancy of in vivo inlays, the replica technique was used, while for the in vitro analysis the serial slice cut technique was performed. All samples were processed for metallographic analysis using SEM.

RESULTS

The measured in vivo inlay marginal gap was 9,06+/-3,37 microns (mean+/-SD), while for in vitro inlay the marginal gap was of 10,47+/-2,09 microns (mean+/-SD). Metallographic analysis showed equiaxial grain of small dimension.

CONCLUSIONS

The results suggest that using the proposed casting technique it is possible to increase marginal adaptation and microstructural properties.

Human dental pulp vasculogenesis evaluated by CD34 antigen expression and morphological arrangement

Vasculogenesis describes the process by which endothelial precursor cells form new blood vessels. To characterize the topography and the cellular processes underlying vascularization of human dental pulp, we examiend the expression of the human hematopoietic progenitor cell antigen CD34. Dental pulps, obtained from deciduous and permanent teeth, were morphologically examined at light- and electron-microscope levels and by expression of CD34. The findings indicate that vasculogenesis of dental pulp is a complicated process starting from single CD34(+) cells. These subsequently coalesce to form solid vascular cords inside the developing connective tissue, which later hollows. Pericytes were embedded within the fully formed microvessels' basement membrane. The presence of CD34(+) endothelial cells in permanent teeth reveals that the process of vasculogenesis persists into adult life, where it contributes to continuous adjustment of vessel and network structures in response to functional needs and dental tissue homeostasis.

Catalase activity in human healthy and inflamed dental pulps

AIM

To examine the catalase activity in clinically healthy and symptomatic human dental pulps to verify if an active defence system against oxidizing agents is present as a response to bacterial invasion.

METHODOLOGY

Thirty-three systemically healthy patients, 18 females and 15 males (ages: 11.0-25.9 years; mean 18.8 +/- 3.6), were the source of the pulp tissue. The condition of the pulps was assessed using clinical and radiographic evaluations. The specimens were recovered by longitudinally grooving and splitting the teeth (if extracted) or during endodontic treatment, and were matched for age and sex between the healthy and inflamed specimen groups. Catalase activity was determined through spectrophotometric methods.

RESULTS

Enzymatic activity was 1126 +/- 343 and 3074 +/- 698 mU mL(-1) x mg of total protein in the healthy and inflamed pulp tissue specimens, respectively. This difference was statistically significant (P<0.01).

CONCLUSIONS

These results indicate a role for catalase during dental pulp inflammation in humans, and may represent an inherent biological defence system against reactive oxidants of this tissue.

[Scanning electron microscopy and light microscopy under polarized light of a submandibular salivary gland calculus]

BACKGROUND

The salivary calculus is an ancient pathologic condition, called sublingual stone by Hyppocrates. It is well-defined from a anatomo-pathologic, diagnostic and topographic viewpoint, though some pathogenesis-related doubts still exist. This work aims at relating the micro-morpho-structural aspect of a salivary calculus of remarkable dimensions with the current calculogenetic hypotheses.

METHODS

A 1.1 g salivary calculus removed from the initial section of Wrthon s duct in the right-hand submandibular gland of a 42 year old male has been studied. Following the fixation in 4% buffered formalin and the inclusion in resin, it was serially sectioned in 15-20 micron slices. Some sections were coloured with toluidine blue O and acid fuchsin. The exeresis of the calculus was carried out intraorally, with marsupialization under local anesthesia. The analysis was performed using a SEM with backscattered electrons and a polarised and transmitted light microscope.

RESULTS

The investigations have outlined the presence of various organic cores and a concentric, stratiform architecture interrupted by radial elements.

CONCLUSIONS

The formation of this calculus may be due to mixed secondary lithiasis resulting from the formation of colloids and crystalloids.

Provisional gold-resin restoration executed through an indirect-direct procedure: a clinical report

This clinical report describes the treatment of a patient with a procedure that solves structural strength problems of conventional acrylic resin prostheses. This procedure requires less maintenance and is more resistant to wear. In addition, this procedure reduces chair time compared with conventional provisional resin restorations

[Alloy telescopic crowns. Clinical indications]

This work involves a partially edentate subject fitted with a denture on conical crowns. Of the methods at present used in patients with few teeth, this is considered one of the most satisfactory for dentist and patient. In cases in which the remaining teeth are moveable, a denture on magnets can be utilized. A correct oral hygiene is emphasized to favour the duration of the tooth-denture combination.