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1.
Curr Probl Cardiol ; 49(9): 102699, 2024 Sep.
Article in English | MEDLINE | ID: mdl-38852913

ABSTRACT

BACKGROUND: Cardiovascular diseases (CVD) is the major cause of mortality globally, with increasing evidence suggesting a link between periodontitis, and CVD. This study aims to explore the association between periodontitis and CVD, and the impact of periodontal therapy on cardiovascular health. METHODS: This review synthesized findings from preclinical and clinical studies, without publication year restrictions, examining periodontitis and CVD through various lenses. Scientific databases were inspected with keywords related to periodontitis and CVD. RESULTS: The review identifies a substantial association between periodontitis and an increased risk of several CVD, supported by both epidemiological and interventional studies. Results suggest the complexity of the relationship, influenced by factors like the severity of periodontitis and the presence of other systemic conditions. Clinical data indicates that periodontal therapy, particularly non-surgical periodontal therapy, may reduce systemic inflammatory markers and thus may play a role in the primary and secondary prevention of CVD events, highlighting the potential of periodontal therapy to not only maintain oral health but also to modulate cardiovascular risk factors. CONCLUSIONS: Current evidence supports a significant association between periodontitis and increased cardiovascular risk, promoting integrated healthcare approaches that consider oral health as a key-component of cardiovascular care and wellbeing.


Subject(s)
Cardiovascular Diseases , Oral Health , Periodontitis , Humans , Cardiovascular Diseases/prevention & control , Cardiovascular Diseases/therapy , Cardiovascular Diseases/etiology , Cardiovascular Diseases/epidemiology , Periodontitis/therapy , Periodontitis/complications , Heart Disease Risk Factors , Risk Factors
2.
Materials (Basel) ; 15(6)2022 Mar 16.
Article in English | MEDLINE | ID: mdl-35329645

ABSTRACT

The present review deals with bioactive glasses (BGs), a class of biomaterials renowned for their osteoinductive and osteoconductive capabilities, and thus widely used in tissue engineering, i.e., for the repair and replacement of damaged or missing bone. In particular, the paper deals with applications in periodontal regeneration, with a special focus on in vitro, in vivo and clinical studies. The study reviewed eligible publications, identified on the basis of inclusion/exclusion criteria, over a ranged time of fifteen years (from 1 January 2006 to 31 March 2021). While there are many papers dealing with in vitro tests, only a few have reported in vivo (in animal) research, or even clinical trials. Regardless, BGs seem to be an adequate choice as grafts in periodontal regeneration.

3.
Biology (Basel) ; 11(3)2022 Mar 05.
Article in English | MEDLINE | ID: mdl-35336776

ABSTRACT

Biophysical energies are a versatile tool to stimulate tissues by generating biopotentials. In particular, pulsed electromagnetic field (PEMF) stimulation has intrigued researchers since the 1970s. To date, many investigations have been carried out in vivo, but a gold standard treatment protocol has not yet been defined. The main obstacles are represented by the complex setting of PEMF characteristics, the variety of animal models (including direct and indirect bone damage) and the lack of a complete understanding of the molecular pathways involved. In the present review the main studies about PEMF stimulation in animal models with bone impairment were reviewed. PEMF signal characteristics were investigated, as well as their effect on molecular pathways and osseous morphological features. We believe that this review might be a useful starting point for a prospective study in a clinical setting. Consistent evidence from the literature suggests a potential beneficial role of PEMF in clinical practice. Nevertheless, the wide variability of selected parameters (frequency, duration, and amplitude) and the heterogeneity of applied protocols make it difficult to draw certain conclusions about PEMF effectiveness in clinical implementation to promote bone healing. Deepening the knowledge regarding the most consistent results reported in literature to date, we believe that this review may be a useful starting point to propose standardized experimental guidelines. This might provide a solid base for further controlled trials, to investigate PEMF efficacy in bone damage conditions during routine clinical practice.

4.
Materials (Basel) ; 14(11)2021 May 29.
Article in English | MEDLINE | ID: mdl-34072369

ABSTRACT

In the present study, the clinical outcomes obtained using three different protocols of post-operative plaque control for the 4 weeks after surgery were compared. Thirty healthy subjects, presenting at least one periodontal pocket requiring resective surgery, were selected and randomly distributed to three different groups corresponding to respective post-surgical protocols: (A) toothbrushes + chlorhexidine + anti-discoloration system (ADS + CHX); (B) toothbrushes + chlorhexidine (CHX); (C) only toothbrushes. The full-mouth plaque score (FMPS), full-mouth bleeding score (FMBS), probing pocket depth (PPD), recession depth (REC), clinical attachment level (CAL), and bleeding on probing (BoP) were measured in six aspects per tooth (mesio-buccal (MB), buccal (B), disto-buccal (DB), disto-lingual (DL), lingual (L), and mesio-lingual (ML)) at baseline, 3 months, and 6 months after surgery. FMPS and FMBS did not significantly change (p > 0.05), whereas PPD and CAL significantly decreased, and REC significantly increased in all groups during the study (p < 0.05). Clinical results were satisfactory in all cases, with no significant differences between groups 3 months after surgery. Six months after surgery, only PPD-MB was significantly different in the three groups (p < 0.05). Nevertheless, this value was not clinically relevant because the value of PPD-B (about 2 mm) in group C was physiologic. The mechanical plaque control was proven to be fundamental and sufficient in all the six aspects per tooth to guarantee an excellent clinical outcome without the need of chemical plaque control.

5.
Materials (Basel) ; 13(20)2020 Oct 15.
Article in English | MEDLINE | ID: mdl-33076580

ABSTRACT

A novel bioactive glass containing therapeutic ions with enhanced biocompatibility was designed and produced by the classical melt-quenching route. Starting from a very promising composition (Bio_MS), which combined bioactivity and high crystallization temperature, the ratio between some oxides was tailored to obtain a new and more reactive (in terms of dissolution rate) bioactive glass, called BGMSN (composition in mol%: 6.1 Na2O, 31.3 CaO, 5 MgO, 10 SrO, 2.6 P2O5, 45 SiO2). The aim of this work was to produce a bioactive glass with a good biological performance, preserving, at the same time, the high crystallization temperature achieved for Bio_MS; this is strategic in order to avoid undesired crystalline phases during thermal treatments, which can undermine the bioactivity and even the stability of final products. A complete characterization of the novel bioactive glass was performed in terms of thermal, mechanical and biological properties and in vitro bioactivity. The thermal behavior of the bioactive glass was studied by heating microscopy, differential thermal analysis (DTA) and optical dilatometry; BGMSN showed a very high crystallization temperature and a high sinterability parameter, thus being suitable for applications where thermal treatments are required, such as sintered samples, coatings and scaffolds. Mechanical properties were investigated by the micro-indentation technique. The in vitro biological properties were evaluated by means of both direct and indirect cell tests, i.e., neutral red (NR) uptake and MTT assay, using murine long bone osteocyte Y4 (MLO-Y4) cells: the cellular viability of BGMSN was higher compared to cellular viability of 45S5, both in direct and indirect tests. Finally, the in vitro bioactivity test by soaking samples in simulated body fluid (SBF) showed high dissolution rate, with a good rate of formation of hydroxyapatite.

6.
Materials (Basel) ; 13(12)2020 Jun 23.
Article in English | MEDLINE | ID: mdl-32585873

ABSTRACT

Passive commercial gauzes were turned into interactive wound dressings by impregnating them with a chitosan suspension. To further improve healing, and cell adhesion and proliferation, chitosan/bioactive glass wound dressings were produced with the addition of (i) 45S5, (ii) a Sr- and Mg-containing bioactive glass, and (iii) a Zn-containing bioactive glass to the chitosan suspension. SEM and FTIR analyses evidenced positive results in terms of incorporation of bioactive glass particles. Bioactivity was investigated by soaking chitosan-based bioactive glass wound dressings in simulated body fluid (SBF). Cell viability, proliferation, and morphology were investigated using NIH 3T3 (mouse embryonic fibroblast) cells by neutral red (NR) uptake and MTT assays. Furthermore, the wound-healing rate was evaluated by means of the scratch test, using NIH 3T3. The results showed that bioactive glass particles enhance cell adhesion and proliferation, and wound healing compared to pure chitosan. Therefore, chitosan-based bioactive glass wound dressings combine the properties of the organic matrix with the specific biological characteristics of bioactive glasses to achieve chitosan composites suitable for healing devices.

7.
Materials (Basel) ; 13(10)2020 May 15.
Article in English | MEDLINE | ID: mdl-32429291

ABSTRACT

(1) Background: a cell evaluation focused to verify the self-regenerative antioxidant activity is performed on cerium doped bioactive glasses. (2) Methods: the glasses based on 45S5 Bioglass®, are doped with 1.2 mol%, 3.6 mol% and 5.3 mol% of CeO2 and possess a polyhedral shape (~500 µm2). Glasses with this composition inhibit oxidative stress by mimicking catalase enzyme (CAT) and superoxide dismutase (SOD) activities; moreover, our previous cytocompatibility tests (neutral red (NR), 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and Bromo-2-deoxyUridine (BrdU)) reveal that the presence of cerium promotes the absorption and vitality of the cells. The same cytocompatibility tests were performed and repeated, in two different periods (named first and second use), separated from each other by four months. (3) Results: in the first and second use, NR tests indicate that the presence of cerium promotes once again cell uptake and viability, especially after 72 h. A decrease in cell proliferation it is observed after MTT and BrdU tests only in the second use. These findings are supported by statistically significant results (4) Conclusions: these glasses show enhanced proliferation, both in the short and in the long term, and for the first time such large dimensions are studied for this kind of study. A future prospective is the implantation of these bioactive glasses as bone substitute in animal models.

8.
J Biomed Mater Res B Appl Biomater ; 108(6): 2579-2589, 2020 08.
Article in English | MEDLINE | ID: mdl-32092225

ABSTRACT

In this present study, in vitro characterization on bioactivity and biocompatibility of the copper-doped hydroxyapatite (Cu-HA) coatings deposited onto Ti6Al4V alloy with increasing copper content obtained using solution precursor plasma spray process were evaluated under simulated body fluid (SBF) and cytotoxicity tests. The growth of flake-like structures was observed at the coatings' surface after 7 days of immersion in SBF. Elemental composition analysis showed a calcium-deficient carbonate-containing apatite for the grown layer. Broadening of the HA peaks were also observed in the X-ray diffraction patterns and infrared absorption spectra of the immersed coatings associated with the possible formation of an amorphous layer at the surface of the coatings. Copper incorporation does not alter the bioactivity of HA but only slowed down for 10 mol% copper content. Cytotoxicity evaluation using MTT assays showed that 3 mol% Cu-HA coating was not toxic under in vitro characterizations.


Subject(s)
Coated Materials, Biocompatible , Copper , Durapatite/chemistry , Alloys , Animals , Calcium/chemistry , Carbonates/chemistry , Cell Line , Cell Survival , Coated Materials, Biocompatible/toxicity , Durapatite/toxicity , Materials Testing , Mice , Microscopy, Electron, Scanning , Solutions , Spectrophotometry, Infrared , Titanium , X-Ray Diffraction
9.
Materials (Basel) ; 12(19)2019 Oct 08.
Article in English | MEDLINE | ID: mdl-31597232

ABSTRACT

(1) Background: valuation of the bioactivity and cytocompatibility of P2O5-free and CeO2 doped glasses. (2) Methods: all glasses are based on the Kokubo (K) composition and prepared by a melting method. Doped glassed, K1.2, K3.6 and K5.3 contain 1.2, 3.6, and 5.3 mol% of CeO2. Bioactivity and cytotoxicity tests were carried out in simulated body fluid (SBF) solution and murine osteocyte (MLO-Y4) cell lines, respectively. Leaching of ions concentration in SBF was determined by inductively coupled plasma mass spectrometry (ICP-MS) and optical emission spectrometry (ICP-OES). The surface of the glasses were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. (3) Results: P2O5-free cerium doped glasses are proactive according to European directives. Cerium increases durability and retards, but does not inhibit, (Ca10(PO4)6(OH)2, HA) formation at higher cerium amounts (K3.6 and K5.3); however, cell proliferation increases with the amount of cerium especially evident for K5.3. (4) Conclusions: These results enforce the use of P2O5-free cerium doped bioactive glasses as a new class of biomaterials.

10.
Mater Sci Eng C Mater Biol Appl ; 104: 109910, 2019 Nov.
Article in English | MEDLINE | ID: mdl-31500031

ABSTRACT

Novel bioactive glasses with different amount of zinc oxide (ZnO), namely 2, 3.8 and 5 mol%, were designed, produced by a melt-quenching route and investigated in terms of biological performance. Proper amounts of ZnO were added to a previously developed bioactive glass containing strontium and magnesium, characterized by an ultra-high crystallization temperature. Thus, the aim of the work was to obtain a bioactive glass with high crystallization temperature in view of an eventual thermal treatment, as well as antibacterial properties (due to the antimicrobial effect of zinc, as reported in the literature). Bioactivity was investigated by immersion in Simulated Body Fluid (SBF), which is a commonly used protocol to evaluate samples' bioactivity in vitro. Additionally, in order to exclude the possible cytotoxicity of Zn containing bioactive glasses, a biological investigation using MLO-Y4 cells was carried out, both by direct (NR uptake) and indirect (MTT) contact tests. Finally, the antibacterial effects of the produced bioactive glasses against Staphylococcus epidermidis (Gram-positive), Pseudomonas aeruginosa and Escherichia coli (both Gram-negative) were investigated.


Subject(s)
Anti-Bacterial Agents/pharmacology , Glass/chemistry , Temperature , Zinc/pharmacology , Animals , Bacteria/drug effects , Biocompatible Materials/pharmacology , Cell Line , Cell Shape/drug effects , Crystallization , Mice , Microbial Sensitivity Tests , X-Ray Diffraction
11.
Materials (Basel) ; 12(13)2019 Jun 28.
Article in English | MEDLINE | ID: mdl-31261615

ABSTRACT

Bioactive glasses (BGs) are currently employed in a wide range of medical and dentistry applications by virtue of their bone-bonding ability. The incorporation of BGs into a collagen matrix may be used to combine the regenerative potential of these materials with the specific biological advantages of collagen. However, most of the collagen/BG composites reported in the literature are scaffolds and there is a lack of moldable putties or injectable systems. Here, granules of an innovative BG containing strontium and magnesium were mixed with collagen and PEG to obtain a putty (BGMS/C) suitable for dental applications. For the sake of comparison, granules of 45S5 Bioglass®, the gold standard among BGs, were used to prepare a 45S5/collagen putty. Both the composites were evaluated in vitro with respect to murine fibroblasts. The materials showed an excellent biocompatibility, making them interesting for possible applications in dentistry and reconstructive surgery. Moreover, BGMS/C seems to stimulate cell proliferation.

12.
Materials (Basel) ; 12(4)2019 Feb 16.
Article in English | MEDLINE | ID: mdl-30781522

ABSTRACT

The cytocompatibility of potential bioactive cerium-containing (Ce3+/Ce4+) glasses is here investigated by preparing three different glasses with increasing amount of doping CeO2 (1.2, 3.6 and 5.3 mol% of CeO2, called BG_1.2, BG_3.6 and BG_5.3, respectively) based on 45S5 Bioglass® (called BG). These materials were characterized by Environmental Scanning Electron Microscopy (ESEM) and infrared spectroscopy (FTIR) after performing bioactivity tests in Dulbecco's Modified Eagle Medium (DMEM) solution, and the ions released in solution were determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Optical Emission Spectrometry (ICP-OES). The data obtained clearly show that the glass surfaces of BG, BG_1.2 and BG_3.6 were covered by hydroxyapatite (HA), while BG_5.3 favored the formation of a cerium phosphate crystal phase. The cytotoxicity tests were performed using both murine long bone osteocyte-like (MLO-Y4) and mouse embryonic fibroblast (NIH/3T3) cell lines. The cerium-containing bioactive glasses show an increment in cell viability with respect to BG, and at long times, no cell aggregation and deformation were observed. The proliferation of NIH/3T3 cells increased with the cerium content in the glasses; in particular, BG_3.6 and BG_5.3 showed a higher proliferation of cells than the negative control. These results highlight and enforce the proposal of cerium-doped bioactive glasses as a new class of biomaterials for hard-tissue applications.

13.
Mater Sci Eng C Mater Biol Appl ; 96: 757-764, 2019 Mar.
Article in English | MEDLINE | ID: mdl-30606588

ABSTRACT

A novel bioglass composition (BGMS10), containing strontium and magnesium and characterized by an ultra-high crystallization temperature, is here employed for the first time to produce different composites with the addition of specific amounts of hydroxyapatite. After an investigation of the samples' bioactivity in vitro in a simulated body fluid solution (SBF) - according to a widely used protocol -, the biocompatibility of the new materials was tested with respect to murine fibroblasts both by direct and indirect tests, in order to evaluate possible cytotoxic effects of the materials' eluates. Although none of the samples were cytotoxic and their bioactivity in SBF increased with the increasing amount of the glass in the composite, thus showing the best performance in the case of pure BGMS10 glass, the findings of the biological investigation did not confirm those arising from the SBF assay. Surprisingly, while the composites with the lowest glass amount showed an enhanced biocompatibility in direct tests, on the contrary their biological responsiveness is typically lower in the indirect ones, based on filtered materials' extracts. This fact could be ascribed to the high release of particulate from the composites, which are more porous than the glassy samples: in fact, such pronounced dissolution may affect both the cell viability and the absorbance readings used in the colorimetric assays. The pure BGMS10 glass showed the best biological response only in the cell proliferation test (which is an indirect contact test), being able to stimulate cell proliferation in particular after 24 h. For these reasons, when considering bioactive glasses and bioglass-based composites, the results of direct cell culture assays should be integrated with those obtained by indirect ones, while the findings regarding the in vitro bioactivity in SBF should be interpreted with great care.


Subject(s)
Body Fluids/chemistry , Cell Proliferation/drug effects , Ceramics , Materials Testing , Animals , Ceramics/pharmacokinetics , Ceramics/pharmacology , Humans , Magnesium/chemistry , Magnesium/pharmacokinetics , Magnesium/pharmacology , Mice , NIH 3T3 Cells , Strontium/chemistry , Strontium/pharmacokinetics , Strontium/pharmacology
14.
Materials (Basel) ; 11(11)2018 Nov 08.
Article in English | MEDLINE | ID: mdl-30413108

ABSTRACT

In this work, a set of novel bioactive glasses have been tested in vivo in an animal model. The new compositions, characterized by an exceptional thermal stability and high in vitro bioactivity, contain strontium and/or magnesium, whose biological benefits are well documented in the literature. To simulate a long-term implant and to study the effect of the complete dissolution of glasses, samples were implanted in the mid-shaft of rabbits' femur and analyzed 60 days after the surgery; such samples were in undersized powder form. The statistical significance with respect to the type of bioactive glass was analyzed by Kruskal⁻Wallis test. The results show high levels of bone remodeling, several new bone formations containing granules of calcium phosphate (sometimes with amounts of strontium and/or magnesium), and the absence of adverse effects on bone processes due to the almost complete glass dissolution. In vivo results confirming the cell culture outcomes of a previous study highlighted that these novel bioglasses had osteostimulative effect without adverse skeletal reaction, thus indicating possible beneficial effects on bone formation processes. The presence of strontium in the glasses seems to be particularly interesting.

15.
J Craniomaxillofac Surg ; 46(1): 107-118, 2018 Jan.
Article in English | MEDLINE | ID: mdl-29128150

ABSTRACT

Clinical advantages of piezosurgery have been already proved. However, few investigations have focused on the dynamics of bone healing. The aim of this study was to evaluate, in adult rabbits, bone regeneration after cranial linear osteotomies with two piezoelectrical devices (Piezosurgery® Medical - PM and Piezosurgery® Plus - PP), comparing them with conventional rotary osteotomes (RO). PP was characterized by an output power three times higher than PM. Fifteen days after surgery, histomorphometric analyses showed that the osteotomy gap produced with PM and PP was about half the size of that produced by RO, and in a more advanced stage of recovery. Values of regenerated bone area with respect to the total osteotomy area were about double in PM and PP samples compared with RO ones, while the number of TRAP-positive (tartrate-resistant acid phosphatase positive) osteoclasts per linear surface showed a significant increase, suggesting greater bone remodelling. Under scanning electron microscopy, regenerated bone displayed higher cell density and less mineralized matrix compared with pre-existent bone for all devices used. Nanoindentation tests showed no changes in elastic modulus. In conclusion, PM/PP osteotomies can be considered equivalent to each other, and result in more rapid healing compared with those using RO.


Subject(s)
Bone Regeneration , Osteotomy , Piezosurgery , Skull/surgery , Skull/ultrastructure , Animals , Rabbits
16.
Mater Sci Eng C Mater Biol Appl ; 79: 286-295, 2017 Oct 01.
Article in English | MEDLINE | ID: mdl-28629020

ABSTRACT

In this work a set of novel materials for bone tissue regeneration have been tested in vivo in an animal model. In fact, despite many studies have been devoted to amorphous 45S5 Bioglass®, there is lack in the literature of works aimed to study the in vivo performance of heat-treated - and thus partially crystallized - 45S5. As widely reported, crystallization limits the bioactivity of 45S5 and is the main reason that prevents a broader use of this material. Thus, in the present work, a recently developed bioactive glass (BG_Ca/Mix) is tested, since previous investigations demonstrated that BG_Ca/Mix is particularly promising by virtue of both its high bioactivity and lower tendency to crystallize with respect to 45S5. BG_Ca/Mix sintered powders and two composites, which contain BG_Ca/Mix and an increasing percentage (20wt% or 70wt%) of hydroxyapatite (HA), were considered. As a term of comparison, 45S5 sintered powders were also studied. The samples were implanted in rabbits' femurs and harvested after 8weeks. The histological analysis demonstrated that BG_Ca/Mix has an osteoconductive ability slightly higher than that of 45S5 glass-ceramics, followed by that of the composites, which may represent the starting point for obtaining systems with degradation rate tailored for a given clinical application. Moreover, the 45S5 samples were locally cracked, probably because of a non-uniform dissolution in the physiological environment. On the contrary such cracks, which could lead to implant instability and unsuitable mechanical performance, were not observed in BG_Ca/Mix.


Subject(s)
Bone and Bones , Animals , Bone Regeneration , Ceramics , Crystallization , Durapatite , Glass
17.
Mater Sci Eng C Mater Biol Appl ; 72: 566-575, 2017 Mar 01.
Article in English | MEDLINE | ID: mdl-28024623

ABSTRACT

The composition of a CaO-rich silicate bioglass (BG_Ca-Mix, in mol%: 2.3 Na2O; 2.3 K2O; 45.6 CaO; 2.6 P2O5; 47.2 SiO2) was modified by replacing a fixed 10mol% of CaO with MgO or SrO or fifty-fifty MgO-SrO. The thermal behaviour of the modified glasses was accurately evaluated via differential thermal analysis (DTA), heating microscopy and direct sintering tests. The presence of MgO and/or SrO didn't interfere with the thermal stability of the parent glass, since all the new glasses remained completely amorphous after sintering (treatment performed at 753°C for the glass with MgO; at 750°C with SrO; at 759°C with MgO and SrO). The sintered samples achieved good mechanical properties, with a Young's modulus ranging between 57.9±6.7 for the MgO-SrO modified composition and 112.6±8.0GPa for the MgO-modified one. If immersed in a simulated body fluid (SBF), the modified glasses after sintering retained the strong apatite forming ability of the parent glass, in spite of the presence of MgO and/or SrO. Moreover, the sintered glasses, tested with MLO-Y4 osteocytes by means of a multi-parametrical approach, showed a good bioactivity in vitro, since neither the glasses nor their extracts caused any negative effect on cell viability or any inhibition on cell growth. The best results were achieved by the MgO-modified glasses, both BGMIX_Mg and BGMIX_MgSr, which were able to exert a strong stimulating effect on the cell growth, thus confirming the beneficial effect of MgO on the glass bioactivity.


Subject(s)
Biocompatible Materials/chemistry , Ceramics/chemistry , Magnesium Oxide/chemistry , Silicates/chemistry , Strontium/chemistry , Animals , Biocompatible Materials/toxicity , Calcium Compounds/chemistry , Cell Line , Cell Survival/drug effects , Hot Temperature , Mice , Oxides/chemistry , Spectrum Analysis, Raman , X-Ray Diffraction
18.
Mater Sci Eng C Mater Biol Appl ; 51: 196-205, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25842126

ABSTRACT

Bioactive glass/hydroxyapatite composites for bone tissue repair and regeneration have been produced and discussed. The use of a recently developed glass, namely BG_Ca/Mix, with its low tendency to crystallize, allowed one to sinter the samples at a relatively low temperature thus avoiding several adverse effects usually reported in the literature, such as extensive crystallization of the glassy phase, hydroxyapatite (HA) decomposition and reaction between HA and glass. The mechanical properties of the composites with 80wt.% BG_Ca/Mix and 20wt.% HA are sensibly higher than those of Bioglass® 45S5 reference samples due to the presence of HA (mechanically stronger than the 45S5 glass) and to the thermal behaviour of the BG_Ca/Mix, which is able to favour the sintering process of the composites. Biocompatibility tests, performed with murine fibroblasts BALB/3T3 and osteocites MLO-Y4 throughout a multi-parametrical approach, allow one to look with optimism to the produced composites, since both the samples themselves and their extracts do not induce negative effects in cell viability and do not cause inhibition in cell growth.


Subject(s)
Body Fluids/chemistry , Cell Survival/drug effects , Ceramics/chemistry , Ceramics/toxicity , Durapatite/chemistry , Durapatite/toxicity , Glass/chemistry , 3T3 Cells , Animals , Compressive Strength , Humans , Materials Testing , Mice , Nanocomposites/chemistry , Nanocomposites/toxicity
19.
Mater Sci Eng C Mater Biol Appl ; 43: 573-86, 2014 Oct.
Article in English | MEDLINE | ID: mdl-25175252

ABSTRACT

A new sol-gel (SG) method is proposed to produce special bioactive glasses (BG_Ca family) characterized by a low tendency to devitrify. These formulations, derived from 45S5 Bioglass®, are characterized by a high content of CaO (45.6 mol%) and by a partial or complete substitution of sodium oxide with potassium oxide (total amount of alkaline oxides: 4.6 mol%), which increases the crystallization temperature up to 900°C. In this way, it is possible to produce them by SG preserving their amorphous nature, in spite of the calcination at 850°C. The sintering behavior of the obtained SG powders is thoroughly investigated and the properties of the sintered bodies are compared to those of the melt-derived (M) counterparts. Furthermore, the SG glass powders are successfully used to produce scaffolds by means of a modified replication technique based on the combined use of polyurethane sponges and polyethylene particles. Finally, in the view of a potential application for bone tissue engineering, the cytotoxicity of the produced materials is evaluated in vitro.


Subject(s)
Biocompatible Materials , Gels , Glass , Tissue Scaffolds , Crystallization , Crystallography, X-Ray , Microscopy, Electron, Scanning , Porosity , Thermogravimetry
20.
Aval. psicol ; 11(3): 395-406, dez. 2012. tab
Article in Portuguese | LILACS | ID: lil-688399

ABSTRACT

O objetivo foi identificar evidências da existência ou não de respostas populares (RP) nas verbalizações de 289 estudantes com idade entre 06 e 15 anos, às 21 lâminas do FAT. As RP permitem medir o ajustamento social e intelectual da pessoa em avaliação. Neste estudo, adotou-se a razão de 1/3, ou seja, uma resposta em cada três sujeitos. A análise das respostas permitiu a identificação de conteúdos que foram codificados em categorias, por meio da análise de conteúdo. Após tabulou-se as respostas dos estudantes, divididos em quatro grupos, considerando idade e sexo. Constatou-se que: não houve diferenças expressivas no que diz respeito ao conteúdo das categorias entre os quatro grupos analisados e que a média de RP dadas por cada participante foi superior ao apontado pela literatura como mínimo necessário para pessoas ajustadas socialmente.


The objective was to identify evidences on the existence or not of popular responses (PR) in the verbalization of 289 students aged between 06 and 15 years old, on the 21 pictures of the FAT. The PRs allow the social and intellectual adjustment of the subject in an assessment process. For this study the ratio of 1/3 was used, meaning one response on each three subjects. The responses have permitted the identification of the contents that were codified in categories. After that the tabulation results of the students was made, who were divided in four groups, considering age and sex. It was verified that: there has not been presented too significant differences among the four groups in relation to the content of the categories and the average of the RP given by each participant was superior than the minimum described in the literature as necessary for socially adjusted people.


El objetivo fue identificar evidencias de la existencia o no de respuestas populares (RP) en las verbalizaciones de 289 estudiantes de edades entre 06 y 15 años, en las 21 láminas del FAT. Las RP permiten medir el ajuste social e intelectual de la persona en evaluación. En este estudio, se adoptó la relación de 1/3, es decir, una respuesta a cada tres sujetos. El análisis de las respuestas permitió la identificación de contenidos que fueron codificados en categorías. Después se tabularon las respuestas de los estudiantes divididos en cuatro grupos conforme la edad y el sexo. Los resultados muestran que no hubo diferencias significativas en cuanto al contenido de las categorías entre los cuatro grupos analizados y que el promedio de las RP dadas por cada uno de los participantes fue mayor que la indicada en la literatura como el mínimo necesario para personas ajustadas socialmente.


Subject(s)
Humans , Male , Female , Child , Adolescent , Family Relations , Projective Techniques , Psychological Tests , Social Adjustment
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