Scaffolds of PCL combined to bioglass: synthesis, characterization and biological performance.

Biomaterials may be useful in filling lost bone portions in order to restore balance and improve bone regeneration. The objective of this study was to produce polycaprolactone (PCL) membranes combined with two types of bioglass (Sol-Gel and melt-quenched) and determine their physical and biological properties. Membranes were produced through electrospinning. This study presented three experimental groups: pure PCL membranes, PCL-Melt-Bioglass and PCL-Sol-gel-Bioglass. Membranes were characterized using Scanning Electron Microscopy, Fourier Transform Infrared Spectrophotometry (FTIR), Energy-Dispersive Spectroscopy and Zeta Potential. The following in vitro tests were performed: MTT assay, alkaline phosphatase activity, total protein content and mineralization nodules. Twenty-four male rats were used to observe biological performance through radiographic, fracture energy, histological and histomorphometric analyses. The physical and chemical analysis results showed success in manufacturing bioactive membranes which significantly enhanced cell viability and osteoblast differentiation. The new formed bone from the in vivo experiment was similar to that observed in the control group. In conclusion, the electrospinning enabled preparing PCL membranes with bioglass incorporated into the structure and onto the surface of PCL fibers. The microstructure of the PCL membranes was influenced by the bioglass production method. Both bioglasses seem to be promising biomaterials to improve bone tissue regeneration when incorporated into PCL.

Systemic and local effects of radiotherapy: an experimental study on implants placed in rats.

OBJECTIVES: Evaluate the modulating effect of ionizing radiation, blood cytokine levels, and bone remodeling of the interface around the implant to understand the radiation mechanisms which can impair the implants receptor site. MATERIAL AND METHODS: Sixty rats were submitted to grade V titanium implants in the femurs and were divided into the following groups: no-irradiation (N-Ir): control group with implant only; early-irradiation (E-Ir): implant + irradiation after 24 h; late-irradiation (L-Ir): implant + irradiation after 4 weeks; and previous-irradiation (P-Ir): irradiation + implant after 4 weeks. The animals in the E-Ir, L-Ir, and P-Ir groups were irradiated in two fractional stages of 15 Gy. At 3 days, 2 weeks, and 7 weeks after the final procedure, five animals were randomly euthanized per group. Serum levels of TNF-ɑ, IL-1ß, TGF-ß, IL-6, M-CSF, and IL-10 were measured from blood collected prior to euthanasia using the ELISA test. The pieces containing the implants were subjected to immunohistochemical labeling using the tartrate acid resistant to phosphatase, osteocalcin, and caspase-3 markers and mCT. The ANOVA test was used for statistical analysis, and the Tukey multiple comparison test (p < 0.05) was applied. RESULTS: The results indicated that ionizing radiation modifies the production of pro- and anti-inflammatory serum cytokines, the expression of proteins involved in bone remodeling and cellular apoptosis, as well as changes in bone formation. CONCLUSIONS: The results suggests that a longer period between radiotherapy and implant placement surgery when irradiation occurs prior to implant installation would allow the recovery and renewal of bone cells and avoid future failures in osseointegration. CLINICAL RELEVANCE: The search for modifications caused by ionizing irradiation in bone tissue can indicate the ideal period for implant placement without affecting the osseointegration process.

Anti-inflammatory and anti-resorptive efficacy of adrenergic blockers on late replanted rat incisors.

BACKGROUND/AIM: In addition to their anti-inflammatory and anti-osteoclastogenesis properties, adrenergic blockers may also have promising anti-resorptive effects that can prevent root resorption when teeth are replanted because of avulsion. The aim of this study was to investigate the effects of phentolamine (Ph) and propranolol (Pr) in gels on the repair process of late replanted rat incisors. A further aim was to evaluate the biocompatibility of both drugs to human periodontal ligament fibroblasts (HPDLFs). MATERIALS AND METHODS: Forty-eight maxillary right incisors were extracted from male Wistar rats, stored in paper napkins for 60 minutes, and randomly allocated to one of eight groups (n = 6). The root canal, root surface, and alveolus were treated with 0.75 µg/mL Ph gel (Ph0.75), 10 µg/mL Ph gel (Ph10), 100 µg/mL Ph gel (Ph100), 2.5 µg/mL Pr gel (Pr2.5), 10 µg/mL Pr gel (Pr10), 100 µg/mL Pr gel (Pr100), or sodium carboxymethylcellulose gel (CMC) before replantation. In the control group (CH), only the root canal was treated with calcium hydroxide paste. Thirty days following surgery, the animals were euthanized, and the right hemimaxilla was removed to perform micro-CT and histomorphometric analysis to determine osteoclastic activity. Ethanolic solutions of Ph10 and Pr10 were selected based on the in vivo study, and the viability of HPDLFs stimulated with lipopolysaccharide was determined by MTT assays. RESULTS: The micro-CT and histomorphometric analysis revealed no significant differences among the treatments (P > .05). The presence of active osteoclasts was significantly decreased in the Ph10 and Pr10 groups (P < .05). Ph10 and Pr10 produced statistically similar cell survival rates compared to the control group (P > .05). CONCLUSIONS: Ph10 and Pr10 significantly decreased osteoclastogenesis in delayed replanted rat teeth and were not cytotoxic toward HPDLFs.

In vitro osteogenesis process induced by hybrid nanohydroxyapatite/graphene nanoribbons composites.

Carbon nanotubes combine high bend and mechanical strength, which is advantageous for many structural and biomedical purposes. Recently, some biomaterials, based on carbon nanostructures and nanohydroxyapatite (nHAp), have been investigated as bone substitutes in order to improve regeneration. The aim of this study was to access the expression of some RNA transcripts (involved in the process of osteoblast differentiation) by mesenchymal stem cells cultured over different nanocomposite surfaces. A multi-walled carbon nanotube (MWCNT) was firstly grown using chemical vapor deposition and then exfoliated using chemical and oxygen plasma treatments to obtain graphene nanoribbons (GNR). The hybrid composites nHAp/GNR were prepared using the wet method assisted by ultrasound irradiation with different amounts of GNR (1.0, 2.0 and 3.0 wt %). Five groups were tested in cell cultures. Group 1: synthesized nHAp; Group 2: synthesized GNR; Group 3: nHAp and 1.0% of GNR; Group 4: nHAp and 2.0% of GNR and group 5: nHAp and 3.0% of GNR. Real time reverse transcription polymerase chain reactions were performed, and all data was submitted to Kruskal Wallis and Dunn tests, at a significance level of 5%. As a result, three nanocomposites with different proportions of GNR were successfully produced. After cell culture, the expression of osteogenic genes demonstrated no significant differences among the groups and periods. However, bone morphogenetic protein II (BMP II), integrin binding sialoprotein (IBSP), and Osterix highest expressions were observed in the group containing 3.0% of GNR. In conclusion, our hybrid composites may be useful in bone interventions requiring mesenchymal stem cell differentiation into osteoblasts for healing.

Correlation of intratumoral lymphatic microvessel density, vascular endothelial growth factor C and cell proliferation in salivary gland tumors.

Lymphatic dissemination is one of the most important pathways for metastasis in many solid tumors, including head and neck carcinomas. The lymphatic growth of cancer has been used as a significant independent adverse prognostic factor and provides information about tumor progression. Salivary gland tumors present different prognoses and have the ability to develop metastases; however, this information regarding the lymphatic spread is scarce. This paper quantifies the lymphatic microvessel density (LMD) in benign and malignant salivary gland tumors and analyzes the relationship between LMD and tumor expression of vascular endothelial growth factors C (VEGF-C) and the proliferative index. The results show that there is no correlation between LMD, VEGF-C and the proliferative index in the majority of salivary gland tumors analyzed, apart from polymorphous low-grade carcinoma which exhibits statistical correlation between LMD and the proliferative index (p < 0.05). This correlation probably does not indicate a poor prognosis for this PLGA, since this is a low metastasizing carcinoma of the salivary glands. Different from other solid tumors, such as breast or prostatic carcinomas, there is no correlation between VEGF-C and LMD in salivary gland tumors, and so these traits are not able to estimate the metastatic risk or the prognosis of these tumors.

Porous titanium and Ti-35Nb alloy: effects on gene expression of osteoblastic cells derived from human alveolar bone.

Tests on titanium alloys that possess low elastic modulus, corrosion resistance and minimal potential toxicity are ongoing. This study aimed to evaluate the behavior of human osteoblastic cells cultured on dense and porous Titanium (Ti) samples comparing to dense and porous Ti-35 Niobium (Ti-35Nb) samples, using gene expression analysis. Scanning electronic microscopy confirmed surface porosity and pore interconnectivity and X-ray diffraction showed titanium beta-phase stabilization in Ti-35Nb alloy. There were no differences in expression of transforming growth factor-ß, integrin-ß1, alkaline phosphatase, osteopontin, macrophage colony stimulating factor, prostaglandin E synthase, and apolipoprotein E regarding the type of alloy, porosity and experimental period. The experimental period was a significant factor for the markers: bone sialoprotein II and interleukin 6, with expression increasing over time. Porosity diminished Runt-related transcription factor-2 (Runx-2) expression. Cells adhering to the Ti-35Nb alloy showed statistically similar expression to those adhering to commercially pure Ti grade II, for all the markers tested. In conclusion, the molecular mechanisms of interaction between human osteoblasts and the Ti-35Nb alloy follow the principal routes of osseointegration of commercially pure Ti grade II. Porosity impaired the route of transcription factor Runx-2.

Healing of normal and osteopenic bone with titanium implant and low-level laser therapy (GaAlAs): a histomorphometric study in rats.

The study investigates the influence of low-level laser therapy (LLLT) on bone healing in the femur of osteopenic and normal rats with titanium implants. Ovariectomy and control group were randomly submitted to LLLT, which was applied by gallium-aluminum-arsenium (GaAlAs) laser at the surgical site before and after placing the implant, for seven times. Histomorphometric and statistical analysis were performed. Most irradiated groups showed higher values than the nonirradiated groups. The GaAlAs infrared diode laser may improve the osseointegration process in osteopenic and normal bone, particularly based on its effects in the initial phase of bone formation.

Development and characterization of ceramic-polymeric hybrid scaffolds for bone regeneration: incorporating of bioactive glass BG-58S into PDLLA matrix.

In recent years, there has been a notable surge of interest in hybrid materials within the biomedical field, particularly for applications in bone repair and regeneration. Ceramic-polymeric hybrid scaffolds have shown promising outcomes. This study aimed to synthesize bioactive glass (BG-58S) for integration into a bioresorbable polymeric matrix based on PDLLA, aiming to create a bioactive scaffold featuring stable pH levels. The synthesis involved a thermally induced phase separation process followed by lyophilization to ensure an appropriate porous structure. BG-58S characterization revealed vitreous, bioactive, and mesoporous structural properties. The scaffolds were analyzed for morphology, interconnectivity, chemical groups, porosity and pore size distribution, zeta potential, pH, in vitro degradation, as well as cell viability tests, total protein content and mineralization nodule production. The PDLLA scaffold displayed a homogeneous morphology with interconnected macropores, while the hybrid scaffold exhibited a heterogeneous morphology with smaller diameter pores due to BG-58S filling. The hybrid scaffold also demonstrated a pH buffering effect on the polymer surface. In addition to structural characteristics, degradation tests indicated that by incorporating BG-58S modified the acidic degradation of the polymer, allowing for increased total protein production and the formation of mineralization nodules, indicating a positive influence on cell culture.

Electrospun polylactic acid scaffolds with strontium- and cobalt-doped bioglass for potential use in bone tissue engineering applications.

The development of nanoscale biomaterials associated with polymers has been growing over the years, due to their important structural characteristics for applications in biological systems. The present study aimed to produce and test polymeric scaffolds composed of polylactic acid (PLA) fibers associated with a 58S bioglass doped with therapeutic ions for use in tissue engineering. Three 58S Bioglass was obtained by the sol-gel route, pure and doped with 5% strontium and cobalt ions. Solutions of 7% PLA was used as control and added the three different bioglass, 4% of 58S bioglass (PLA-BG), 4% bioglass-doped strontium (PLA-BGSr) and 4% bioglass-doped cobalt (PLA-BGCo). Scaffolds were produced through electrospinning process, and was characterized chemical and morphologically. The in vitro tests were performed using mesenchymal cells cultures from femurs of nine rats, grown in osteogenic supplemented total culture medium. After osteoblastic differentiation induction cell viability, alkaline phosphatase activity, total protein content quantification, and visualization of mineralization nodule tests were performed. Analysis of normal distribution used the Shapiro-Wilk test (nanofibers diameter and biological assay). Data were compared using the Kruskal-Wallis nonparametric test (p = 0.05). The bioglasses produced proved to be free of nitrate, chlorinated and nano-sized, with effective incorporation of therapeutic ions in their structure. All materials showed cell viability (>70%), total protein production, and alkaline phosphatase activity. It was possible to develop polylactic acid scaffolds associated with 58S bioglass doped with therapeutic ions without cytotoxicity. Scaffolds characteristics appear to sustain its application in bone tissue engineering.

Novel production method of porous surface Ti samples for biomedical application.

A porous implant material with adequate pore structure and the appropriate mechanical properties for bone ingrowth has long been sought. This article presents details of the development, characterization and in vivo evaluations of powder metallurgy-processed titanium samples exhibiting a dense core with an integrated porous surface for biomedical applications. A space-holder method was applied to investigate the effects of different percentages and particle sizes of the urea on bone neoformation in 30 rabbits. The samples were previously characterized using scanning electron microscopy and mechanical testing. After 8 and 12 weeks of implantation, bone ingrowth was histologically and histometrically analyzed and push-out testing was performed. This study demonstrated that the association of a dense core integrated with the greatest number of interconnected pores of the smallest size is a promising biomaterial for bone tissue engineering. This sample exhibits appropriate mechanical properties combined with increased bone ingrowth, providing enhanced resistance to displacement.

Effect of the nanofilm-coated zirconia ceramic on resin cement bond strength.

Background. New surface treatments have been proposed to expand the clinical indications of zirconia prostheses. This study aimed to evaluate the effect of silica and fluorine nanofilms on zirconia ceramic on the resin cement bond strength. Methods. Zirconia blocks and discs underwent different surface treatments: untreated zirconia (CON), sandblasted, silica-coated alumina particles (30 µm) (SC), silica nanofilm (SN), and fluorine nanofilm (FN). Nanofilm deposition was performed through plasma enhanced chemical vapor deposition (PECVD). Zirconia surfaces were characterized on disks by morphology (atomic force microscopy, AFM), chemical analysis (x-ray photoelectron spectroscopy, XPS), and contact angle analysis. A silane coupling agent was applied on each treated surface, and a cylinder of resin cement was built up. Half of the specimens in each group were submitted to 6000 thermal cycles (TC). Bond strength was analyzed using the shear test, and the fractographic analysis was performed with stereomicroscopy and SEM/EDS. Statistical analysis was performed through one-way ANOVA and Tukey test in the non-aged and aged specimens. Results. Nanofilms modified the zirconia surface, which became more hydrophilic and chemically reactive. Chemical bonding between Si-O was found in SN, and FN promoted a fluorination process on the ceramic surface, converting zirconia into zirconium oxyfluoride. Specimens of the SN (TC) group failed on pre-testing. FN (TC) bond strength (3.8 MPa) was lower than SC (TC) and CON (TC) after shearing. Adhesive failure predominated in the experimental groups. Silica nanofilm failure occurred after aging. Conclusion. Silica and fluorine nanofilms deposited by PECVD did not promote effective bonding between zirconia and resin cement.

Immunohistochemical study of the expression of fatty acid synthase and Ki-67 in salivary gland tumors.

BACKGROUND: The enzyme fatty acid synthase plays a fundamental role in the biosynthesis of fatty acids. Several recent studies have demonstrated a high fatty acid synthase expression in malignant tumors. Few studies have been conducted in oral and salivary gland tumors describing the fatty acid synthase expression. METHODS: This study evaluated and compared, by immunohistochemical reaction, the expression of fatty acid synthase and Ki-67 in salivary gland tumors. The immunohistochemical study used the streptavidin-biotin-peroxidase technique, with antibodies anti-fatty acid synthase and anti-Ki-67. The fatty acid synthase was analyzed by scores, considering the intensity of labeling, quantity of labeled cells and histological component. The Ki-67 was analyzed by counting of one thousand cells, calculating the quantity of positive cells in regions with higher density of labeling. Statistical analysis was performed using the Pearson and Mann-Whitney correlation tests. RESULTS: There was greater fatty acid synthase expression in pleomorphic adenoma compared to other tumors, and predominance of Ki-67 in malignant tumors. Among these, the mucoepidermoid carcinoma presented the highest proliferation rate. The expression of fatty acid synthase and Ki-67 did not present correlation between the tumors analyzed, except in pleomorphic adenomas, with statistically significant relationship between them. CONCLUSION: It is suggested that the fat metabolism in salivary gland tumors is related to maintenance of cell differentiation. Its expression prevailed in benign tumors, while Ki-67 prevailed in the mucoepidermoid carcinoma, demonstrating its high proliferation rate, followed by the cystic adenoid carcinoma and polymorphous low grade adenocarcinoma.

Experimental systemic virulence of oral Candida dubliniensis isolates in comparison with Candida albicans, Candida tropicalis and Candida krusei.

There are no previous studies on the comparative virulence of Candida dubliniensis with other non-albicans species. The aim of this study was to compare the virulence and infection kinetics of C. dubliniensis and other species. Candida albicans, C. dubliniensis, Candida tropicalis and Candida krusei (reference strains) were inoculated intravenously in mice. For infection kinetics evaluation, a group of five animals were sacrificed after 6 h, 3, 7, 14 and 21 days. Microbiological evaluations (liver, spleen, kidneys, lungs and brain) and histopathological examination of the kidney were performed. The results of virulence evaluation were analysed using Kaplan-Meier survival analysis (5%). Candida dubliniensis-inoculated mice survived for longer periods compared with those with C. albicans (P = 0.005). No differences were detected in relation to C. tropicalis (P = 0.326) and C. krusei (P = 0.317). Most of the organs were persistently colonised by C. albicans and C. dubliniensis even by day 21. Tendency of C. krusei clearance was observed in all organs. Fungal masses and renal lesions were observed after inoculation of C. albicans, C. dubliniensis and C. tropicalis. Within the limits of the study, data on survival rate and dissemination capacity suggest that C. dubliniensis is less virulent than C. albicans.

Effect of low-calcium diet and grind diet on bone turnover of ovariectomized female rats.

OBJECTIVE: The variety of methodologies used to investigate ovariectomized female rats shows different results, which makes a clinical application of these results difficult. The purpose of this work was to evaluate the effect of masticatory effort reduction and of low-calcium diet on maxillary bone turnover of ovariectomized female rats. STUDY DESIGN: Eighty-four female rats were divided into four groups of 21 animals each as follows: SHAM--sham-operated; OVZ--ovariectomized and fed a standard commercial diet; LCD--fed a low calcium diet, and GCD--fed a grind commercial diet. The inferior first molars were extracted bilaterally 15 days after the ovariectomy, and the animals were euthanized 3, 5 and 8 weeks after ovaries removal. The maxillae were embedded in methylmetacrilate. The results were submitted to analysis of variance. RESULTS: The daily mineral apposition rate lowered with time and was not different between SHAM and OVZ groups. The trabecular bone volume of SHAM and OVZ animals was similar and decreased with time. The GCD animals presented the lowest means and the LCD the highest in comparison to the OVZ group. CONCLUSION: It was concluded that ovariectomy and a low calcium diet did not cause significant maxillary bone loss in the first molar region, and even in the absence of the antagonist tooth, they did not cause maxillary bone turnover. The grind commercial diet is a good alternative for the study of maxillary bone loss in ovariectomized female rats.

Cyclosporine A - Induced gingival overgrowth and proliferating cell nuclear antigen expression in experimental periodontitis.

The most important microscopic characteristic of Cyclosporine A-induced gingival overgrowth is fibroepithelial hyperplasia. OBJECTIVE: The objective was to investigate the influence of previous exposure to Cyclosporine A over gingival epithelium in experimental periodontitis in rats. METHODS: Twenty Wistar rats with 12 weeks-old were divided into four groups with 5 animals each: Control Group (CG); Cyclosporine Group (CsAG); Ligature group (LG) and Cyclosporine and Ligature Group (CsALG). Daily doses of CsA (10 mg/kg) were applied to CsAG and CsALG during 60 days since the beginning of the experiment and, a ligature was placed in LG and CsALG 30 days after the beginning of the experiment. After 60 days, animals were euthanized and gingival tissue was processed to histomorphometric analysis of epithelial thickness (mm2), immunohistochemical expression of PCNA (%) and inflammatory response. Data were analyzed by Kruskal-Wallis and Mann Whitney at 0.05 significance level. RESULTS: Considering epithelial thickness, CG was thinner than all groups, CsALG was the largest and CsAG and LG were similar between each other. Regarding the PCNA expression CG (16.46 ± 9.26) was similar to CsAG (34.47 ± 19.75) and, LG (59.02 ± 10.33) was similar to CsALG (40.59 ± 18.25). Significant difference (p < 0.05) occurred only in inflammation presence comparing CG/LG and CsAG/CsALG. A weak positive correlation between the number of PCNA+ and inflammatory cells (p = 0.001; r = 0.611) was observed. CONCLUSION: Based on these results it was concluded that the enlargement of gingival epithelium observed in experimental periodontitis can be increased by previous exposition to CsA and inflammatory conditions enhanced proliferative activity of the keratinocytes.

Bilateral mandibular buccal bifurcation cyst: a case report emphasizing the role of imaging examination in the diagnosis.

A mandibular buccal bifurcation cyst is an inflammatory cyst that usually occurs on the buccal aspect of the permanent mandibular first molar of children. This lesion is diagnosed by an association of radiographic, clinical, and histological features. We report a bilateral case of mandibular buccal bifurcation cyst and discuss the main findings of this entity. A 7-year-old girl presented pain and delayed dental eruption in the posterior mandibular region. A cone beam computed tomography was performed and revealed hypodense lesions involving the crown and root of the mandibular first molars, with expansion of the buccal cortical and lingual tilting of the molar roots. A biopsy was carried out, and the common features of an inflammatory odontogenic cyst were histologically observed. The final diagnosis was bilateral mandibular buccal bifurcation cyst. Clinicians need to be aware of this diagnostic possibility in cases of mandibular cysts in children-especially when bilateral-to perform the correct treatment, which should not involve the extraction of the affected tooth.

Presence of mast cells and the expression of metalloproteinase 9 in the gingiva of ovariectomized rats with periodontal disease.

BACKGROUND: The host's answer has an important role in periodontal disease, and the mast cells have a prime role. Such cells seem to be influenced by estrogen deficiency. The objective was to evaluate the mast cells and the expression of metalloproteinase(MMP)-9 in periodontal disease induced in ovariectomized rats. METHODS: For that purpose, 36 rats were used; 18 ovariectomized (OVX) and another 18 Sham-operated (SHAM). After 60 days the periodontal disease was induced by a ligature around the first lower right molars (group P). The opposite side was the control group (group C). The euthanasia occurred 3, 7 and 14 days after the placement of the ligature. The gingiva was removed and analyzed histochemically and immunohistochemically to quantify the mast cells and to analyze MMP 9 expression. RESULTS: By comparing the groups SHAM-P and C and groups OVX-C and P, it was noted that mast cells from group C were higher than P in all experimental periods. When comparing groups SHAM-C and OVX-C, significant factors were not found. When comparing groups SHAM-P and OVX-P, there was an inclination for mast cells reduction with time. The MMP-9 expression was related to the presence of periodontitis. CONCLUSIONS: It was concluded that periodontitis led to mast cells reduction and MMP-9 increase. The ovariectomy itself did not alter the MMP-9 expression and did not influence the presence of mast cells in rat papilla, however, when associated to inflammation led to a reduction of mast cells.

In vitro and in vivo biological performance of porous Ti alloys prepared by powder metallurgy.

Titanium (Ti) and Ti-6 Aluminium-4 Vanadium alloys are the most common materials in implants composition but ß type alloys are promising biomaterials because they present better mechanical properties. Besides the composition of biomaterial, many factors influence the performance of the biomaterial. For example, porous surface may modify the functional cellular response and accelerate osseointegration. This paper presents in vitro and in vivo evaluations of powder metallurgy-processed porous samples composed by different titanium alloys and pure Ti, aiming to show their potential for biomedical applications. The porous surfaces samples were produced with different designs to in vitro and in vivo tests. Samples were characterized with scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and elastic modulus analyses. Osteogenic cells from newborn rat calvaria were plated on discs of different materials: G1-commercially pure Ti group (CpTi); G2-Ti-6Al-4V alloy; G3-Ti-13 Niobium-13 Zirconium alloy; G4-Ti-35 Niobium alloy; G5-Ti-35 Niobium-7 Zirconium-5 Tantalum alloy. Cell adhesion and viability, total protein content, alkaline phosphatase activity, mineralization nodules and gene expression (alkaline phosphatase, Runx-2, osteocalcin and osteopontin) were assessed. After 2 and 4 weeks of implantation in rabbit tibia, bone ingrowth was analyzed using micro-computed tomography (µCT). EDS analysis confirmed the material production of each group. Metallographic and SEM analysis revealed interconnected pores, with mean pore size of 99,5µm and mean porosity of 42%, without significant difference among the groups (p>0.05). The elastic modulus values did not exhibit difference among the groups (p>0.05). Experimental alloys demonstrated better results than CpTi and Ti-6Al-4V, in gene expression and cytokines analysis, especially in early experimental periods. In conclusion, our data suggests that the experimental alloys can be used for biomedical application since they contributed to excellent cellular behavior and osseointegration besides presenting lower elastic modulus.

Influence of Adrenergic Neuromodulation during Induction of Periodontitis in Rats.

The action of the sympathetic nervous system in the control of bone remodeling and immunoinflammatory responses is the basis of the hypothesis that its modulation can influence the progress of periodontal disease. The aim of this study was to analyze the effects of the blockade and of the activation of ß-adrenergic receptors in periodontal disease in rats. Thirty-two rats were divided into four groups: 1) animals with induced periodontitis that received propranolol (a non-selective ß-adrenergic antagonist) 0.1 mg/kg (PRO); 2) animals with induced periodontitis that received isoproterenol (a non- selective ß-adrenergic agonist) 0.75 mg/kg (ISO); 3) animals with induced periodontitis and without drug treatment (L); and 4) animals without induced periodontitis and without drug treatment - control (C). After 14 days of treatment, the rats were euthanized. Right hemi-mandibles were removed and lingual alveolar bone loss measurements were made under a stereomicroscope. Left hemi-mandibles were decalcified and submitted to routine histological preparation for the evaluation of alveolar bone loss in furcation regions, amount of gingival collagen, and immunohistochemistry for receptor activator of nuclear factor-kappa B ligand (RANKL)/osteoprotegerin (OPG) ratio. Animals treated with isoproterenol had significantly more lingual alveolar bone loss than others. The percentage of collagen in gingiva was greater in the propranolol group than in the isoproterenol group. No statistical differences were found among groups with periodontal disease in any other evaluations. The activation of ß-adrenergic receptors increased the lingual alveolar bone loss; however, in the model used, the use of ß-adrenergic antagonist drugs was not able to modulate the host response significantly. Activation and inhibition of ß-receptors have antagonistic actions in collagen degradation in animals with periodontal disease.

Expression of betacatenin in carcinoma in pleomorphic adenoma, pleomorphic adenoma and normal salivary gland: an immunohistochemical study.

OBJECTIVES: Pleomorphic adenomas are the most frequent type of epithelial salivary gland neoplasms, and their malignant counterpart, the carcinoma in pleomorphic adenomas, is much less common. Beta-catenin is a cell adhesion molecule associated with the invasion and metastasis of carcinomas of the head and neck, esophagus. The objective of this study was to detect the expression of beta-catenin in pleomorphic adenomas, carcinomas in pleomorphic adenomas and normal salivary glands to discuss its role in the development of these two lesions. STUDY DESIGN: The expression of beta-catenin (BD Transduction Laboratories) was analyzed by immunohistochemistry in formalin-fixed, paraffin embedded specimens by the avidin-biotin-peroxidase complex method in 16 pleomorphic adenomas (12 from minor salivary glands), 3 carcinomas in pleomorphic adenomas (all from palate) and 10 normal salivary glands as control group (5 from major and 5 from minor salivary glands). RESULTS: All cases of glands, adenomas and carcinomas in pleomorphic adenomas have membranous and cytoplasmic immunostaining. Nuclear beta-catenin immunostaining was not observed. The antibody presented a fine granular arrangement in the cytoplasm and cellular membrane of duct and acinic cells. Higher beta-catenin index rates were seen mainly in salivary gland ducts and in ductal structures in the adenomas and carcinomas in pleomorphic adenomas. There was protein loss in pleomorphic adenomas and cytoplasmic accumulation in carcinoma in pleomorphic adenomas. CONCLUSIONS: The present study showed participation of the loss of beta-catenin adhesion molecule in the development of pleomorphic adenoma, and that the cytoplasmic accumulation of the molecule takes part in the malignant transformation of the pleomorphic adenoma into carcinoma in pleomorphic adenoma.