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1.
J Biomed Mater Res B Appl Biomater ; 108(5): 1868-1878, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-31840930

RESUMO

Osteopenia and osteoporosis affect over 40 million US adults 50 years and older. Both diseases are strongly influenced by estrogen and nutritional-mineral deficiencies. This study investigates the efficacy of orally delivered synthetic-bone-mineral (SBM), a newly developed calcium phosphate based biomaterial, on reversing bone loss induced by these two critical deficiencies. Thirty 3-month-old female rats were randomly allocated to either control-sham surgery on normal diet; or one of the four experimental groups: Sham surgery on a low mineral diet (LMD), ovariectomized (OVX) on LMD, OVX on LMD with SBM with/without fluoride (F). The rats were sacrificed after 6 months, at 9-month-old. After 6 months, although all groups lost bone mineral density relative to controls, the supplemented OVX rats showed higher bone mineral density than their unsupplemented counterparts. The 2 SBM supplemented groups improved bone loading capacity by 28.1 and 35.4% compared to the OVX LMD group. Bones from supplemented rats exhibited higher inorganic/organic ratios. The addition of F did not have a significant influence on bone loss. Our findings suggest that SBM supplement is effective in maintaining bone health and offsetting the deleterious effects of estrogen and/or mineral deficiencies on bone density, microarchitecture, and strength.


Assuntos
Densidade Óssea/efeitos dos fármacos , Doenças Ósseas Metabólicas/metabolismo , Osso e Ossos/efeitos dos fármacos , Fosfatos de Cálcio/metabolismo , Estrogênios/farmacologia , Minerais/farmacologia , Animais , Osso e Ossos/metabolismo , Dieta , Dietoterapia , Feminino , Humanos , Testes Mecânicos , Ratos , Ratos Sprague-Dawley , Fatores de Tempo
2.
J Biomed Mater Res A ; 105(8): 2218-2227, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28380669

RESUMO

Various surface modifications have been tried for enhancing osseointegration of the dental implants like mechanical and/or chemical treatments and deposition of calcium phosphate coatings. The objective of this research was to develop calcium-phosphate based thin coatings with antibacterial and bioactive properties for potential application in dental implants. Titanium (Ti) discs were immersed in different calcifying solutions: CaP (positive control), F-CaP, Zn-CaP, and FZn-CaP and incubated for 24 h. Negative control was uncoated Ti discs. Coated surfaces were characterized using X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. Antibacterial properties were tested using Porphyromonas gingivalis because of its strong association with periodontal and peri-implant infections. Bacterial adhesion and colonization were studied at different timepoints. The coated surfaces had compositional characteristics similar to that of bone mineral and they inhibited the growth, colonization and adherence of P. gingivalis, resulted in reduced thickness of biofilms and bacterial inhibition in the culture medium as compared to the positive and negative controls (p < 0.05). There was no significant difference between the experimental groups (p > 0.05). It has been previously demonstrated that these coatings have excellent in vitro bioactivity (formed carbonate hydroxyapatite when immersed in a simulated body fluid). Such coatings can enhance osseointegration and prevent infection in implants, thereby improving the success rates of implants. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2218-2227, 2017.


Assuntos
Antibacterianos/química , Fosfatos de Cálcio/química , Materiais Revestidos Biocompatíveis/química , Implantes Dentários/microbiologia , Titânio/química , Antibacterianos/farmacologia , Infecções por Bacteroidaceae/prevenção & controle , Biofilmes/efeitos dos fármacos , Fosfatos de Cálcio/farmacologia , Materiais Revestidos Biocompatíveis/farmacologia , Durapatita/química , Humanos , Porphyromonas gingivalis/efeitos dos fármacos , Porphyromonas gingivalis/fisiologia , Propriedades de Superfície , Titânio/farmacologia , Difração de Raios X
3.
J Biomed Mater Res A ; 104(7): 1622-32, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26914814

RESUMO

Calcium and other trace mineral supplements have previously demonstrated to safely improve bone quality. We hypothesize that our novel calcium-phosphate based biomaterial (SBM) preserves and promotes mandibular bone formation in male and female rats on mineral deficient diet (MD). Sixty Sprague-Dawley rats were randomly assigned to receive one of three diets (n = 10): basic diet (BD), MD or mineral deficient diet with 2% SBM. Rats were sacrificed after 6 months. Micro-computed tomography (µCT) was used to evaluate bone volume and 3D-microarchitecture while microradiography (Faxitron) was used to measure bone mineral density from different sections of the mandible. Results showed that bone quality varied with region, gender and diet. MD reduced bone mineral density (BMD) and volume and increased porosity. SBM preserved BMD and bone mineral content (BMC) in the alveolar bone and condyle in both genders. In the alveolar crest and mandibular body, while preserving more bone in males, SBM also significantly supplemented female bone. Results indicate that mineral deficiency leads to low bone mass in skeletally immature rats, comparatively more in males. Furthermore, SBM administered as a dietary supplement was effective in preventing mandibular bone loss in all subjects. This study suggests that the SBM preparation has potential use in minimizing low peak bone mass induced by mineral deficiency and related bone loss irrespective of gender. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1622-1632, 2016.


Assuntos
Materiais Biocompatíveis/farmacologia , Densidade Óssea/efeitos dos fármacos , Mandíbula/efeitos dos fármacos , Mandíbula/crescimento & desenvolvimento , Osteogênese/efeitos dos fármacos , Animais , Peso Corporal/efeitos dos fármacos , Fosfatos de Cálcio/farmacologia , Cristalização , Dieta , Feminino , Masculino , Mandíbula/diagnóstico por imagem , Tamanho do Órgão/efeitos dos fármacos , Ratos Sprague-Dawley , Microtomografia por Raio-X
4.
Acta Biomater ; 18: 9-20, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25575855

RESUMO

Various calcium phosphate based coatings have been evaluated for better bony integration of metallic implants and are currently being investigated to improve the surface bioactivity of polymeric scaffolds. The aim of this study was to evaluate the role of calcium phosphate coating and simultaneous delivery of recombinant human bone morphogenetic protein-2 (rhBMP-2) on the in vivo bone regeneration capacity of biodegradable, porous poly(propylene fumarate) (PPF) scaffolds. PPF scaffolds were coated with three different calcium phosphate formulations: magnesium-substituted ß-tricalcium phosphate (ß-TCMP), carbonated hydroxyapatite (synthetic bone mineral, SBM) and biphasic calcium phosphate (BCP). In vivo bone regeneration was evaluated by implantation of scaffolds in a critical-sized rabbit calvarial defect loaded with different doses of rhBMP-2. Our data demonstrated that scaffolds with each of the calcium phosphate coatings were capable of sustaining rhBMP-2 release and retained an open porous structure. After 6weeks of implantation, micro-computed tomography revealed that the rhBMP-2 dose had a significant effect on bone formation within the scaffolds and that the SBM-coated scaffolds regenerated significantly greater bone than BCP-coated scaffolds. Mechanical testing of the defects also indicated restoration of strength in the SBM and ß-TCMP with rhBMP-2 delivery. Histology results demonstrated bone growth immediately adjacent to the scaffold surface, indicating good osteointegration and osteoconductivity for coated scaffolds. The results obtained in this study suggest that the coated scaffold platform demonstrated a synergistic effect between calcium phosphate coatings and rhBMP-2 delivery and may provide a promising platform for the functional restoration of large bone defects.


Assuntos
Proteína Morfogenética Óssea 2/farmacologia , Regeneração Óssea/efeitos dos fármacos , Fosfatos de Cálcio/farmacologia , Materiais Revestidos Biocompatíveis/farmacologia , Fumaratos/farmacologia , Polipropilenos/farmacologia , Crânio/efeitos dos fármacos , Alicerces Teciduais/química , Fator de Crescimento Transformador beta/farmacologia , Animais , Preparações de Ação Retardada , Feminino , Humanos , Imageamento Tridimensional , Cinética , Porosidade , Coelhos , Proteínas Recombinantes/farmacologia , Crânio/diagnóstico por imagem , Espectrometria por Raios X , Microtomografia por Raio-X
5.
J Biomed Mater Res B Appl Biomater ; 102(3): 423-9, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24039127

RESUMO

We have developed a calcium phosphate glass (CPG) doped with Zn(2+) or F(-) or combined Zn(2+) and F(-) ions, which are naturally found in the human body and play a dual role in bone formation and antibacterial activity. Previously, we have demonstrated that this family of CPGs has superior osteoconductive and resorbable properties in vivo. This study aimed to investigate the antibacterial property of CPGs incorporating Zn(2+) and/or F(-) . We used Streptococcus mutans as a model organism because it is one of the major human oral pathogens and an early colonizer, and it has been associated with several oral infections, such as dental caries, periodontitis, and peri-implantitis. CPGs of 0.01 and 0.05 g were incubated with S. mutans for 0, 2, 4, and 6 h. Serial dilutions were plated in triplicate and colony forming units were determined. The antimicrobial effect of CPG incorporating Zn(2+) or F(-) was greater than CPG incorporating both these ions. CPG without doping produced a moderate antimicrobial effect. This family of CPGs, previously shown to promote new bone formation in vivo, is demonstrated to have superior bactericidal properties.


Assuntos
Antibacterianos/farmacologia , Fosfatos de Cálcio/farmacologia , Vidro , Células 3T3 , Algoritmos , Animais , Biofilmes/efeitos dos fármacos , Desenvolvimento Ósseo/efeitos dos fármacos , Adesão Celular , Óxido de Magnésio/química , Camundongos , Testes de Sensibilidade Microbiana , Peso Molecular , Osseointegração , Osteoclastos , Fluoreto de Sódio/química , Espectrometria de Fluorescência , Streptococcus mutans/efeitos dos fármacos , Óxido de Zinco/química
6.
Mater Sci Eng C Mater Biol Appl ; 33(7): 4188-96, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23910332

RESUMO

3D porous scaffolds are relevant biomaterials to bone engineering as they can be used as templates to tissue reconstruction. The aim of the present study was to produce and characterize in vitro 3D magnesium-carbonate apatite/collagen (MCA/col) scaffolds. They were prepared by using biomimetic approach, followed by cross-linking with 0.25% glutaraldehyde solution (GA) and liofilization. Results obtained with Fourier-transform infrared spectroscopy (FT-IR) confirmed the type-B carbonate substitution, while by X-ray diffraction (XRD), a crystallite size of ~10nm was obtained. Optical and electron microscopy showed that the cylindrical samples exhibited an open-porous morphology, with apatite nanocrystals precipitated on collagen fibrils. The cross-linked 3D scaffolds showed integrity when immersed in culture medium up to 14 days. Also, the immersion of such samples into an acid buffer solution, to mimic the osteoclastic resorption environment, promotes the release of important ions for bone repair, such as calcium, phosphorus and magnesium. Bone cells (SaOs2) adhered, and proliferated on the 3D composite scaffolds, showing that synthesis and the cross-linking processes did not induce cytotoxicity.


Assuntos
Apatitas/síntese química , Biomimética/métodos , Colágeno/farmacologia , Alicerces Teciduais/química , Animais , Ânions , Apatitas/química , Apatitas/farmacologia , Bovinos , Linhagem Celular , Humanos , Microscopia Eletrônica de Varredura , Porosidade , Pós , Espectroscopia de Infravermelho com Transformada de Fourier , Células Estromais/citologia , Células Estromais/efeitos dos fármacos , Células Estromais/ultraestrutura , Difração de Raios X
7.
J Biomater Appl ; 27(7): 783-90, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22071355

RESUMO

OBJECTIVES: This study aimed to determine the efficacy of experimental calcium phosphate-based solutions (sCaP) containing fluoride (F), with and without zinc (Zn) ions on reducing susceptibility to acid dissolution and Streptococcus mutans (S. mutans) colonization of dentin surfaces. METHODS: Dentin sections were treated with double distilled water (control) and with sCaP solutions differing in pH and in F(-) and/or Zn(2+) ion concentrations. Solutions A (pH 7); B, C, and D (pH 5.5); solution C, twice Zn(2+) and F(-) ion concentration compared to B; solution D is similar to C but without Zn(2+). The dentin surfaces were characterized using scanning electron microscopy (SEM), x-ray diffraction, and Fourier Transform Infrared spectroscopy. Dissolution was determined in acidic buffer. Bacterial (S. mutans) attachment and growth were evaluated using SEM and Bioquant. Statistical analyses applied analysis of variance (ANOVA) and Duncan's multiple Range test. RESULTS: Compared to control, dentin surfaces treated with sCaP solutions showed: (a) occluded dentin tubules; (b)reduced susceptibility to acid dissolution; and (c) Zn(2+) ions were more effective than F(-) ions in inhibiting bacterial colonization. SIGNIFICANCE: Acidic sCaP containing both F and Zn ions have mineralizing, acid resistance, and antibacterial effects and may be potentially useful as a strategy against dentin caries formation and progression.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Fosfatos de Cálcio/química , Fosfatos de Cálcio/farmacologia , Dentina/efeitos dos fármacos , Streptococcus mutans/efeitos dos fármacos , Ácidos/química , Aderência Bacteriana/efeitos dos fármacos , Dentina/química , Dentina/microbiologia , Dentina/ultraestrutura , Fluoretos/química , Fluoretos/farmacologia , Humanos , Concentração de Íons de Hidrogênio , Streptococcus mutans/crescimento & desenvolvimento , Propriedades de Superfície/efeitos dos fármacos , Zinco/química , Zinco/farmacologia
8.
Int J Biomater ; 2012: 615018, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22778740

RESUMO

The aim of this study was to evaluate differences in bones quality between newly formed bone and cortical bone formed around titanium alloy implants by using X-ray photoelectron spectroscopy. As a result of narrow scan measurement at 4 weeks, the newly formed bone of C1s, P2p, O1s, and Ca2p were observed at a different peak range and strength compared with a cortical bone. At 8 weeks, the peak range and strength of newly formed bone were similar to those of cortical bone at C1s, P2p, and Ca2p, but not O1s. The results from this analysis indicate that the peaks and quantities of each element of newly formed bone were similar to those of cortical bone at 8 weeks, suggestive of a strong physicochemical resemblance.

9.
Arch Oral Biol ; 57(9): 1264-73, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22424637

RESUMO

UNLABELLED: Osteoporosis affects the craniofacial and oral structures and has been associated with periodontal bone loss, tooth loss and reduced jaw bone mass. OBJECTIVE: This study aimed to test the therapeutic efficacy of synthetic bone mineral (SBM) in minimizing alveolar bone loss induced by mineral deficiency in a rat model. SBM consists of a calcium carbonate apatite (similar to bone apatite) matrix incorporating magnesium, zinc, and fluoride ions. DESIGN: Thirty female Sprague Dawley rats (2 months old) were randomly distributed into 3 groups (10 rats per group): GA (control), on basic diet; GB, on mineral deficient (MD) diet; and GC, on MD+SBM. The rats were sacrificed after 3 months, the jawbones were isolated and the soft tissues removed. Bone density was determined using X-ray radiography (Faxitron); mandibular cortical width, panoramic mandibular index, and alveolar resorption degree (M/M ratio) using BioquantOsteo; and bone micro-architecture micro-computed tomography and scanning electron microscopy. RESULTS: Compared to control (GA), the rats on MD diet (GB) experienced significant mandibular bone loss while the rats on MD+SBM diet (GC) experienced significantly less bone loss compared to the GB group. CONCLUSION: SBM, administered orally, may have the potential as an osteoporosis therapeutic agent in minimizing or preventing alveolar bone loss induced by mineral deficiency.


Assuntos
Perda do Osso Alveolar/etiologia , Apatitas/uso terapêutico , Conservadores da Densidade Óssea/uso terapêutico , Carbonato de Cálcio/uso terapêutico , Deficiências Nutricionais/complicações , Minerais , Perda do Osso Alveolar/diagnóstico por imagem , Perda do Osso Alveolar/tratamento farmacológico , Animais , Densidade Óssea/efeitos dos fármacos , Fosfatos de Cálcio/uso terapêutico , Carbonatos/uso terapêutico , Cloretos/uso terapêutico , Modelos Animais de Doenças , Feminino , Imageamento Tridimensional/métodos , Cloreto de Magnésio/uso terapêutico , Doenças Mandibulares/diagnóstico por imagem , Doenças Mandibulares/tratamento farmacológico , Doenças Mandibulares/etiologia , Microrradiografia , Microscopia Eletrônica de Varredura , Osteoporose/etiologia , Potássio/uso terapêutico , Radiografia Panorâmica , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Fluoreto de Sódio/uso terapêutico , Microtomografia por Raio-X/métodos , Compostos de Zinco/uso terapêutico
10.
Arch Oral Biol ; 57(4): 369-75, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22071420

RESUMO

OBJECTIVE: The aim of this study was to evaluate the effects of ZnCl(2) on plaque-growth and vitality pattern of dental biofilm and to determine the optimum zinc concentration for the inhibition of plaque formation. DESIGN: Data were collected from nine volunteers for whom a special-designed acrylic appliance was prescribed after a careful dental check up. The volunteers rinsed twice daily for 2min with ZnCl(2) of 2.5, 5, 10, 20mM as treatment and double distilled water (DDW) as control in respective assigned test weeks. The plaque index (PI) was assessed after 48h of appliance wearing. The glass discs with the adhered biofilm were removed from the splints and stained with two fluorescent dyes. The biofilm thickness (BT) and bacterial vitality of the whole biofilm as well as the mean bacterial vitality (BV) of the inner, middle and outer layers of biofilm were evaluated under confocal laser scanning microscope (CLSM). RESULTS: PI, BT and BV of biofilms treated by various concentrations of ZnCl(2) were reduced significantly when compared with the DDW group (p<0.05). PI, BT and BV of the 2.5mM ZnCl(2) group was significantly higher than groups of 5, 10, 20mM ZnCl(2) (p<0.05). The mean BV of the 3 layers (inner, middle and outer layers) showed that 2.5mM ZnCl(2) was the lowest concentration to inhibit BV in the outer layer, 5mM was the lowest concentration to extend this inhibition of BV to the middle layer, and none of the concentrations investigated in this study has shown any effect on bacteria inhibition in the inner layer. CONCLUSION: Zinc ions exhibited possible inhibitory effects on plaque formation, and have a promising potential to be used as an antibacterial agent in future dentifrices and mouthrinses.


Assuntos
Anti-Infecciosos Locais/farmacologia , Biofilmes/efeitos dos fármacos , Cloretos/farmacologia , Placa Dentária/microbiologia , Antissépticos Bucais/uso terapêutico , Compostos de Zinco/farmacologia , Adulto , Análise de Variância , Anti-Infecciosos Locais/uso terapêutico , Biofilmes/crescimento & desenvolvimento , Cloretos/uso terapêutico , Estudos Cross-Over , Placa Dentária/tratamento farmacológico , Índice de Placa Dentária , Método Duplo-Cego , Feminino , Humanos , Masculino , Microscopia Confocal , Compostos de Zinco/uso terapêutico
11.
Am J Dent ; 24(3): 169-75, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21874938

RESUMO

PURPOSE: To determine the efficacy supersaturated calcium phosphate (CaP) solutions containing fluoride (F) and zinc (Zn) ions in occluding dentin tubules with precipitates less susceptible to acid dissolution and to compare the performance of these solutions with the oxalate solutions containing calcium (Ca) or phosphate (P) ions. METHODS: Dentin sections from human molars divided into groups: Group A - control (treated with double distilled H2O), Groups A1, A2 and A3 were treated with experimental solutions supersaturated with respect to F and Zn-substituted calcium phosphates. Solutions A1 and A2 were similar in composition but differed in pH values (A1, pH 7; A2, pH 5.5). Solutions A2 and A3 were similar in pH (pH 5.5) but the A3 solution had twice the concentrations of F and Zn2+ ions compared to A2. Another group of dentin sections were treated with A3 solution, oxalate solution containing Ca (OX/Ca) and OX solution containing P (OX/P). The control and treated dentin sections were characterized using scanning electron microscopy. RESULTS: All treated dentin sections showed occluded dentin tubules; with the group A3 showing the highest percent of occluded dentin tubules. The precipitates in the dentin tubules treated with A3 remained while those treated with OX/Ca or OX/P dissolved after exposure to an acidic buffer.


Assuntos
Fosfatos de Cálcio/farmacologia , Cariostáticos/farmacologia , Dessensibilizantes Dentinários/farmacologia , Solubilidade da Dentina/efeitos dos fármacos , Dentina/efeitos dos fármacos , Ácidos , Adolescente , Adulto , Apatitas/farmacologia , Soluções Tampão , Cloreto de Cálcio/farmacologia , Cloretos/farmacologia , Dentina/ultraestrutura , Humanos , Concentração de Íons de Hidrogênio , Teste de Materiais , Microscopia Eletrônica de Varredura , Oxalatos/farmacologia , Fosfatos/farmacologia , Compostos de Potássio/farmacologia , Fluoreto de Sódio/farmacologia , Solubilidade , Adulto Jovem , Compostos de Zinco/farmacologia
12.
Int J Biomater ; 2011: 129727, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21760793

RESUMO

BCP are considered the most promising biomaterials for bone reconstruction. This study aims at analyzing the outcomes of patients who received BCP as bone substitutes in orthopaedic surgeries. Sixty-six patients were categorized according to the etiology and morphology of the bone defects and received scores after clinical and radiographic evaluations. The final results corresponded to the combination of both parameters and varied from 5 (excellent result) to 2 or lower (poor result). Most of the patients who presented cavitary defects or bone losses due to prosthesis placement or revision, osteotomies, or arthrodesis showed good results, and some of them excellent results. However, patients with segmental defects equal or larger than 3 cm in length were classified as moderate results. This study established clinical parameters where the BCP alone can successfully support the osteogenic process and where the association with other tissue engineering strategies may be considered.

13.
J Biomed Mater Res B Appl Biomater ; 99(1): 58-69, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21714076

RESUMO

The success of implants in orthopaedic and dental load-bearing applications crucially depends on the initial biological fixation of implants in surrounding bone tissues. Using hydroxyapatite (HA) coating on Ti implant as carrier for bone morphogenetic proteins (BMPs) may promote the osteointegration of implants; therefore, reduce the risk of implant failure. The goal of this study was to develop an HA coating method in conditions allowing the incorporation of protein-based drugs into the coating materials, while achieving a mechanical stable coating on Ti implant. HA coatings were deposited on six different groups of Ti surfaces: control (no pretreatment), pretreated with alkali, acid, heat at 800°C, grit blasted with Al2O3, and grit blasted followed by heat treatment. HA coating was prepared using a two-step procedure. First step was the chemical deposition of a monetite coating on Ti substrate in acidic condition at 75°C and the second step was the hydrolysis of the monetite coating to HA. Coatings were characterized by scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The roughness of substrates and coatings was measured using profilometry technique. The mechanical stability of the coatings deposited on the pretreated substrates was assessed using scratch test. The coatings deposited on the grit-blasted Ti surface demonstrated superior adhesive properties with critical shearing stress 131.6 ± 0.2 MPa.


Assuntos
Materiais Revestidos Biocompatíveis/química , Durapatita/química , Titânio/química , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Próteses e Implantes , Espectrometria por Raios X , Estresse Mecânico , Propriedades de Superfície , Difração de Raios X
14.
J Biomater Appl ; 25(8): 811-24, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-20219846

RESUMO

Biological apatites are characterized by the presence of minor constituents such as magnesium (Mg), chloride (Cl), or fluoride (F) ions. These ions affect cell proliferation and osteoblastic differentiation during bone tissue formation. F-substituted apatites are being explored as potential bonegraft materials. The aim of the present study is to investigate the mechanism of bone formation induced by fluoride-substituted apatite (FAp) by analyzing the effect of FAp on the process of in vivo bone formation. FAps containing different F concentrations (l-FAp: 0.48 wt%, m-FAp: 0.91 wt%, h-FAp: 2.23 wt%) and calcium-deficient apatite (CDA), as positive control, were implanted in rat tibia and bone formation was evaluated by histological examination, immuhistochemistry, in situ hybridization and tartrate-resistant acid phosphatase examinations. The results showed that l-FAp, m-FAp, h-FAp, and CDA biomaterials allowed migration of macrophages, attachment, proliferation, and phenotypic expression of bone cells leading to new bone formation in direct apposition to the particles. However, the l-FAp preparation allowed faster bone conduction compared to the other experimental materials. These results suggest that FAp with low F concentration may be an efficient bonegraft material for dental and medical application.


Assuntos
Apatitas/administração & dosagem , Apatitas/química , Substitutos Ósseos/química , Cálcio/química , Fluoretos/administração & dosagem , Fluoretos/química , Osteogênese/efeitos dos fármacos , Animais , Osso e Ossos/efeitos dos fármacos , Cálcio/administração & dosagem , Diferenciação Celular/efeitos dos fármacos , Osteoclastos/efeitos dos fármacos , Ratos , Tíbia/efeitos dos fármacos , Tíbia/metabolismo
15.
J Mater Sci Mater Med ; 22(1): 1-9, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21052792

RESUMO

Bioactive hydroxyapatite (HA) coating on titanium (Ti) implant can be used as a drug delivery device. A controlled release of drug around the implant requires the incorporation of drug into the coating material during the coating process. HA coating was prepared using a two-step procedure in conditions suitable for simultaneous incorporation of the protein-based drug into the coating material. Monetite coating was deposited on Ti substrate in acidic condition followed by the transformation of the monetite coating to HA. X-ray diffraction (XRD) confirmed the formation of the monetite phase at the first step of the coating preparation, which was transformed into HA at the second step. Fourier transform infrared spectroscopy demonstrated typical bands of a crystallized carbonated HA with A- and B-type substitution, which was confirmed by the XRD refinement of the structural parameters. Scanning electron microscope was used to observe the morphology of monetite and HA coatings. Adhesion of the coatings was measured using a scratch tester. The critical shearing stress was found to be 84.20 ± 1.27 MPa for the monetite coating, and 44.40 ± 2.39 MPa for the HA coating.


Assuntos
Materiais Revestidos Biocompatíveis/análise , Durapatita/análise , Titânio/química , Proteína Morfogenética Óssea 2/administração & dosagem , Proteína Morfogenética Óssea 2/farmacocinética , Materiais Revestidos Biocompatíveis/síntese química , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/metabolismo , Portadores de Fármacos/síntese química , Portadores de Fármacos/química , Portadores de Fármacos/metabolismo , Durapatita/química , Durapatita/farmacocinética , Módulo de Elasticidade , Galvanoplastia/métodos , Testes de Dureza , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Modelos Biológicos , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Titânio/metabolismo , Difração de Raios X
16.
J Biomed Mater Res A ; 95(1): 33-9, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20740598

RESUMO

Our previous study demonstrated that calcium-bonded titanium surface (Ca-Ti) can be obtained by hydrothermal reaction between titanium (Ti) and CaCl(2) and that bone-apatite like formation was observed after immersion in simulated body fluid. The purpose of the study was to determine the in vivo response to Ca-Ti surface using a rodent tibia model. Cylinders of commercially pure Ti were divided into three groups: (1) untreated group; (2) NaOH+hTi group: soaked in 5 mol/L NaOH solution at 60 degrees C then heated at 400 degrees C for 1 h; and (3) Ca-Ti group: hydrothermally treated in the presence of 10 mmol/L CaCl(2) at 200 degrees C for 24 h. The cylinders implanted in surgically created defects in tibias of 8-week old male Wistar rats were retrieved after 1, 2, and 4 weeks. Histomorphometric evaluations were made on stained decalcified thin sections. Results showed that at 1, 2, and 4 week after implantation, respectively, bone contact was 55.2 +/- 16.4%, 88.1 +/- 9.9%, and 96.1 +/- 4.8% for Ca-Ti implants, 5.7 +/- 5.3%, 19.9 +/- 1.2%, 57.4 +/- 4.8% for untreated; and 27.2 +/- 0.7%, 70.9 +/- 7.7%, and 96.0 +/- 5.1% for NaOH+hTi implants. These results suggest that hydrothermal treatment with CaCl(2) provides a bioactive Ca-Ti bonded surface that allows bone formation greater than that obtained with NaOH+heat treated Ti surfaces.


Assuntos
Osso e Ossos/citologia , Cálcio/farmacologia , Titânio/farmacologia , Animais , Implantes Experimentais , Microscopia Eletrônica de Varredura , Ratos , Ratos Wistar , Propriedades de Superfície/efeitos dos fármacos , Fatores de Tempo
17.
J Am Dent Assoc ; 141(7): 871-8, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20592408

RESUMO

BACKGROUND: Few studies have examined utilization of oral health care services among immigrants. The authors examined the determinants of utilization of oral health care among a diverse group of immigrants in New York City. METHODS: The authors examined and interviewed 1,417 foreign-born people, aged 18 to 65 years, who were residents of New York City. They conducted examinations by using criteria established by the National Institute of Dental and Craniofacial Research, Bethesda, Md. The authors used unconditional logistic regression to estimate odds ratios (ORs) and 95 percent confidence intervals for having visited a dentist within the previous year for each of the independent variables. RESULTS: More than 70 percent of the participants lacked dental insurance and only about 31 percent reported that they had visited a dentist within the previous year. Flossing (OR = 1.18), dental insurance (OR = 1.58), having a regular source of dental care (OR = 4.76) and more filled teeth (1.33) were independent predictors of utilization of services. CONCLUSIONS: Having a regular source of dental care and having dental insurance are important predictors of immigrants' utilization of oral health care services in New York City. CLINICAL IMPLICATIONS: The study results suggest the importance of establishing affordable, culturally appropriate, community-based oral health care services to improve the oral health of vulnerable populations.


Assuntos
Assistência Odontológica/estatística & dados numéricos , Serviços de Saúde Bucal/estatística & dados numéricos , Emigrantes e Imigrantes/estatística & dados numéricos , Adolescente , Adulto , Negro ou Afro-Americano/estatística & dados numéricos , Idoso , Asiático/estatística & dados numéricos , Índice CPO , Cárie Dentária/diagnóstico , Dispositivos para o Cuidado Bucal Domiciliar/estatística & dados numéricos , Feminino , Hispânico ou Latino/estatística & dados numéricos , Humanos , Seguro Odontológico/estatística & dados numéricos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Cidade de Nova Iorque , Razão de Chances , Aceitação pelo Paciente de Cuidados de Saúde , Perda da Inserção Periodontal/diagnóstico , Estudos de Amostragem , Inquéritos e Questionários , Adulto Jovem
18.
J Biomed Mater Res A ; 94(2): 371-9, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20186736

RESUMO

Bone repair and regeneration is one of the most extensively studied areas in the field of tissue engineering. All of the current tissue engineering approaches to create bone focus on intramembranous ossification, ignoring the other mechanism of bone formation, endochondral ossification. We propose to create a transient cartilage template in vitro, which could serve as an intermediate for bone formation by the endochondral mechanism once implanted in vivo. The goals of the study are (1) to prepare and characterize type I collagen sponges as a scaffold for the cartilage template, and (2) to establish a method of culturing chondrocytes in type I collagen sponges and induce cell maturation. Collagen sponges were generated from a 1% solution of type I collagen using a freeze/dry technique followed by UV light crosslinking. Chondrocytes isolated from two locations in chick embryo sterna were cultured in these sponges and treated with retinoic acid to induce chondrocyte maturation and extracellular matrix deposition. Material strength testing as well as microscopic and biochemical analyzes were conducted to evaluate the properties of sponges and cell behavior during the culture period. We found that our collagen sponges presented improved stiffness and supported chondrocyte attachment and proliferation. Cells underwent maturation, depositing an abundant extracellular matrix throughout the scaffold, expressing high levels of type X collagen, type I collagen and alkaline phosphatase. These results demonstrate that we have created a transient cartilage template with potential to direct endochondral bone formation after implantation.


Assuntos
Regeneração Óssea/fisiologia , Osso e Ossos/fisiologia , Colágeno/metabolismo , Isoformas de Proteínas/metabolismo , Engenharia Tecidual/métodos , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/metabolismo , Osso e Ossos/citologia , Bovinos , Embrião de Galinha , Condrócitos/citologia , Condrócitos/metabolismo , Colágeno/química , Força Compressiva , Matriz Extracelular/química , Matriz Extracelular/metabolismo , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Isoformas de Proteínas/química , Estresse Mecânico
19.
Acta Biomater ; 5(6): 2169-77, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19269268

RESUMO

The mineral in bone is an impure hydroxyapatite, with carbonate as the chief minor substituent. Fluoride has been shown to stimulate osteoblastic activity and inhibit osteoclastic resorption in vitro. CO(3)- and F-substituted apatite (CFA) has been considered as potential bone graft material for orthopedic and dental applications. The objective of this study was to determine the effects of simultaneously incorporated CO(3) and F on the crystallographic physico-chemical properties of apatite. The results showed that increasing CO(3) and Na content in apatites with relatively constant F concentration caused a decrease in crystallite size and an increase in the extent of calcium release; increasing F content in apatites with relatively constant CO(3) concentration caused an increase in crystallite size and a decrease in the extent of Ca release. These findings suggest that CFAs as bone graft materials of desired solubility can be prepared by manipulating the relative concentrations of CO(3) and F incorporated in the apatite.


Assuntos
Apatitas/química , Substitutos Ósseos/química , Cálcio/química , Fluoretos/química , Absorção , Cristalização/métodos , Difusão , Dureza , Teste de Materiais , Tamanho da Partícula , Porosidade , Solubilidade , Propriedades de Superfície
20.
J Biomed Mater Res B Appl Biomater ; 90(1): 229-37, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19145625

RESUMO

The specific aim of this study was to evaluate the efficacy of well-characterized Mg/Zn/F-CaP preparations (administered by injection) in preventing bone mineral deficiency in ovariectomized (OVX) rats. Donryu rats (4 weeks old, average weight 70 g) were divided into six experimental groups: GN (normal), GC (control, OVX), and OVX rats injected with suspensions of MZF-CaPs (G2, G3, and G4) or with Zn-containing tricalcium phosphate (ZnTCP, G1). The composition of the preparations was G1: 34.1 wt % Ca; 19.5 wt % P; and 6.17 wt % Zn; G2 (#51): 23.7 wt % Ca; 13.6 wt % P; 1.1 wt % Mg; 2.9 wt % Zn, and 1.1 wt % F; G3 (#68): 22.4 wt % Ca; 14.1 wt % P; 2.6 wt % Mg, 2.6 wt % Zn, and 2.3 wt % F; G4 (#76): 28.5 wt % Ca; 15.5 wt % P; 1.9 wt % Mg, 1.8 wt % Zn, and 3.0 wt % F. The suspensions (10 mg/0.2 mL) were injected into the right thigh once a week for 12 weeks. Bone mineral density (BMD) was measured by X-ray computed tomography and bone mechanical strength (BMS) was measured as femoral three-point bending strength. BMD and BMS were significantly higher in the femurs from groups G1, G2, G3, and G4 than from GC. No significant difference was observed in BMD or BMS between the left and right femurs for any group. The results indicate that the injected Mg/Zn/F-CaP compounds were effective in preventing bone loss induced by ovariectomy in rats and suggest that these compounds have potential use for treating osteoporosis.


Assuntos
Fosfatos de Cálcio/administração & dosagem , Ovariectomia , Animais , Peso Corporal , Densidade Óssea , Feminino , Ratos , Tomografia Computadorizada por Raios X , Difração de Raios X
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