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1.
Colloids Surf B Biointerfaces ; 228: 113417, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37356139

RESUMO

Multifunctional surfaces may display the potential to accelerate and promote the healing process around dental implants. However, the initial cellular biocompatibility, molecular activity, and the release of functionalized molecules from these novel surfaces require extensive investigation for clinical use. Aiming to develop and compare innovative surfaces for application in dental implants, the present study utilized titanium disks, which were treated and divided into four groups: machined (Macro); acid-etched (Micro); anodized-hydrophilic surface (TNTs); and anodized surface coated with a rifampicin-loaded polymeric layer (poly(lactide-co-glycolide), PLGA) (TNTsRIMP). The samples were characterized regarding their physicochemical properties and the cumulative release of rifampicin (RIMP), investigated at different pH values. Additionally, differentiated osteoblasts from mesenchymal cells were used for cell viability and qRT-PCR analysis. Antibacterial properties of each surface treatment were investigated against Staphylococcus epidermidis. TNTsRIMP demonstrated controlled drug release for up to 7 days in neutral pH environments. Osteogenic cell cultures indicated that all the evaluated surfaces showed biocompatibility. The TNTs group revealed up-regulated values for bone-related gene quantification in 7 days, followed by the TNTsRIMP group. Furthermore, the antibiotic-functionalized surface revealed effectiveness to inhibit S. epidermidis and stimulate promising conditions for osteogenic cell behavior. Characteristics such as nanomorphology and hydrophilicity were determinants for the up-regulated quantification of osteogenic biomarkers related to early bone maturation, encouraging application in intra-osseous implant surfaces; in addition, antibiotic-functionalized surfaces demonstrated significant higher antibacterial properties compared to the other groups. Our findings suggest that polymeric-antibiotic-loaded coating might be applied for the prevention of early infections, favoring its application in multifunctional surfaces for intra- and/or trans-mucosal components of dental implants, while, hydrophilic nanotextured surfaces promoted optimistic properties to stimulate early bone-related cell responses, favoring its application in bone-anchored surfaces.


Assuntos
Antibacterianos , Implantes Dentários , Antibacterianos/farmacologia , Rifampina/farmacologia , Propriedades de Superfície , Diferenciação Celular , Titânio/farmacologia , Titânio/química , Osseointegração
2.
Nanomaterials (Basel) ; 12(15)2022 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-35957034

RESUMO

Hydrophilic and nanotextured surfaces for dental implants have been reported as relevant properties for early osseointegration. However, these surface characteristics are quite sensitive to oral interactions. Therefore, this pilot study aimed to investigate the superficial alterations caused on hydrophilic nanotubular surfaces after early human saliva interaction. Titanium disks were treated using an anodization protocol followed by reactive plasma application in order to achieve nanotopography and hydrophilicity, additionally; surfaces were stored in normal atmospheric oxygen or wet conditioning. Following, samples were interacted with saliva for 10 min and analyzed regarding physical-chemical properties and cellular viability. Saliva interaction did not show any significant influence on morphological characteristics, roughness measurements and chemical composition; however, hydrophilicity was statistically altered compromising this feature when the samples were stored in common air. Cellular viability tested with pre-osteoblasts cell line (MC3T3-E1) reduced significantly at 48 h on the samples without wet storage after saliva contamination. The applied wet-storage methodology appears to be effective in maintaining properties such as hydrophilicity during saliva interaction. In conclusion, saliva contamination might impair important properties of hydrophilic nanotubular surfaces when not stored in wet conditions, suggesting the need of saliva-controlled sites for oral application of hydrophilic surfaces and/or the use of modified-package methods associated with their wet storage.

3.
Biofouling ; 37(7): 757-766, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34396855

RESUMO

Surface treatments are designed to promote modified implant surfaces with positive interactions with the surrounding living tissues. However, the inadvertent early contact of these surfaces with oral fluids during surgery may lead to undesired conditions affecting osseointegration. This study aimed to investigate the possible alterations in the physico-chemical properties of modified-surfaces caused by early saliva exposure. Titanium (Ti) surfaces were exposed to three different samples of human saliva and later analyzed for protein adhesion, physico-chemical surface alterations, and osteogenic cell-viability. The results indicated that surface roughness was the most significant factor influencing saliva protein adsorption; moreover, hydrophilic surfaces had critically lost their characteristics after contact with saliva. Decreased cell viability was observed in cultures after contact with saliva. Early contact with saliva might negatively influence modified surface properties and local cell viability. Careful surgical insertion of implants with hydrophilic surfaces is recommended, particularly in sites where saliva interaction is prone to occur.


Assuntos
Implantes Dentários , Osseointegração , Humanos , Saliva , Propriedades de Superfície , Titânio
4.
J R Soc Interface ; 17(170): 20200650, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32993437

RESUMO

Micro and nanoscale changes allow the optimization of physico-chemical properties of titanium implant surfaces. Recently UV and plasma treatments have allowed surface hydrophilicity to take increased prominence; however, this beneficial effect is short-lived. The aim of this study is to investigate methodologies post-anodizing treatment to generate and maintain high surface hydrophilicity along with high biocompatibility. Anodized surfaces were characterized regarding physical-chemical properties. Then, surface wettability with nanomorphology was evaluated at different times and with distinct post-treatments: as deposited, with a reactive plasma and UV-light post-treatment, stored in air or deionized (DI) water. Adhesion, alkaline phosphatase (ALP) activity and bone cell viability tests were executed after the incremental treatments. The anodizing process generated a surface with TiO2 nanotubes morphology and micro-roughness. Plasma-treated surfaces resulted in the most hydrophilic samples and this property was maintained for a longer period when those were stored in DI water (angle variation of 7° to 12° in 21 days). Furthermore, plasma post-treatment changed the titanium surface crystalline phase from amorphous to anatase. Anodized surfaces modified by reactive plasma and stored in DI water suggest better hydrophilicity stability, biocompatibility, ALP activity and achievement of crystalline phase alteration, indicating future potential use on biomedical implants.


Assuntos
Nanotubos , Titânio , Interações Hidrofóbicas e Hidrofílicas , Propriedades de Superfície
5.
Int J Oral Maxillofac Implants ; 35(4): 773-781, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32724931

RESUMO

PURPOSE: Surface treatments may significantly affect physical-chemical properties and surface biologic responses. This study aimed to investigate the influence of alterations in the physical-chemical properties of pure titanium with different surface topographies on biocompatibility and early microbiologic response. MATERIALS AND METHODS: Titanium disks were exposed to five different surface treatments created through acid etching and anodizing methods. Surface morphology, 2D and 3D roughness, wettability, biocompatibility, and cell viability were evaluated. Osteoblast adhesion and bacterial adhesion tests were also executed. Data were statistically analyzed using analysis of variance followed by Tukey test, roughness (P < .05), and bacterial proliferation (P < .05). RESULTS: Five different surface morphologies were developed; double acid etching was shown to be significantly rougher than the others. The 2D roughness measurements were shown to be less consistent than the 3D measurements. All surfaces presented biocompatibility to allow cell behavior and differentiation. Osteoblasts presented better evolution in terms of adhesion and behavior in the nanomorphologies. High roughness significantly increased bacterial adhesion. CONCLUSION: Surface treatments may critically alter titanium properties and morphology. Therefore, roughness measurements with a wide area should be used in their evaluation. Nanotextured surfaces show a positive effect on bone cells and antibacterial response; their application is suggested when considering surface texturization for biomedical implants.


Assuntos
Implantes Dentários , Titânio , Aderência Bacteriana , Adesão Celular , Proliferação de Células , Osteoblastos , Propriedades de Superfície
6.
Arch Oral Biol ; 117: 104824, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32623133

RESUMO

OBJECTIVE: Surface alterations have been employed to enhance the osseointegration process in biomedical implants. However, these modifications may influence bacterial adhesion in different ways. Therefore, this study developed five different surfaces and evaluated the Staphylococcus epidermidis growth in early (1 h) and late (24 h) contact. DESIGN: The Titanium (Ti) and Zirconia (Zr) surfaces were divided in five groups and characterized concerning your morphology, roughness, wettability and chemical surface composition. Then, were evaluated regarding bacterial adhesion and biofilm formation/thickness, viability and morphology. RESULTS: Different topographies were manufactured resulting in a variety of combinations of surface properties. High roughness showed significantly higher bacterial adhesion in 1 h, while high hydrophilicity revealed greater bacterial proliferation in 24 h. Morphological changes were not found visually, however the viability test showed some cell membrane damage in the Ti micro and nano groups. CONCLUSIONS: Finally, surface distinct properties influence the growth of S. epidermidis independent of the based-material. Furthermore, some surface properties require precautions for use in contaminated sites according to the increased adhesion of S. epidermidis presented when in contact.


Assuntos
Aderência Bacteriana , Biofilmes , Staphylococcus epidermidis , Titânio , Zircônio/farmacologia , Propriedades de Superfície , Titânio/farmacologia
7.
AMB Express ; 9(1): 51, 2019 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-30993485

RESUMO

The fast evolution of surface treatments for biomedical implants and the concern with their contact with cells and microorganisms at early phases of bone healing has boosted the development of surface topographies presenting drug delivery potential for, among other features, bacterial growth inhibition without impairing cell adhesion. A diverse set of metal ions and nanoparticles (NPs) present antibacterial properties of their own, which can be applied to improve the implant local response to contamination. Considering the promising combination of nanostructured surfaces with antibacterial materials, this critical review describes a variety of antibacterial effects attributed to specific metals, ions and their combinations. Also, it explains the TiO2 nanotubes (TNTs) surface creation, in which the possibility of aggregation of an active drug delivery system is applicable. Also, we discuss the pertinent literature related to the state of the art of drug incorporation of NPs with antibacterial properties inside TNTs, along with the promising future perspectives of in situ drug delivery systems aggregated to biomedical implants.

8.
Aust Endod J ; 45(1): 26-32, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28857353

RESUMO

Chemical comparisons of powder and hydrated forms of calcium silicate cements (CSCs) and calculation of alterations in tricalcium silicate (Ca3 SiO5 ) calcium hydroxide (Ca(OH)2 ) are essential for understanding their hydration processes. This study aimed to evaluate and compare these changes in ProRoot MTA, Biodentine and CEM cement. Powder and hydrated forms of tooth coloured ProRoot MTA, Biodentine and CEM cement were subjected to X-ray diffraction (XRD) analysis with Rietveld refinement to semi-quantitatively identify and quantify the main phases involved in their hydration process. Data were reported descriptively. Reduction in Ca3 SiO5 and formation of Ca(OH)2 were seen after the hydration of ProRoot MTA and Biodentine; however, in the case of CEM cement, no reduction of Ca3 SiO5 and no formation of Ca(OH)2 were detected. The highest percentages of amorphous phases were seen in Biodentine samples. Ettringite was detected in the hydrated forms of ProRoot MTA and CEM cement but not in Biodentine.


Assuntos
Compostos de Alumínio , Cálcio , Bismuto , Compostos de Cálcio , Combinação de Medicamentos , Microscopia Eletrônica de Varredura , Óxidos , Silicatos , Espectrometria por Raios X , Difração de Raios X
9.
J Oral Implantol ; 41(4): e102-9, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24946138

RESUMO

To evaluate the action of recombinant human growth hormone (rhGH) on osseointegration of titanium implants in rabbits. Fourteen adult New Zealand rabbits, aged 30 weeks, were used in the study, and randomly divided into 2 groups. In each animal, 2 (2.2 mm × 6 mm) pure titanium implants were placed in the left tibia. In one group (test group), 1 IU (0.3 mg) of rhGH as a lyophilized powder was applied to each osteotomy site prior to implant placement. Only titanium implants were placed in osteotomy sites of the other group (control). Animals were humanely killed at 14 and 42 days after surgery, and samples were then prepared for histologic analysis and biomechanical test. The biomechanical test showed tensile pull-out stress values of 33.88 N/cm(2) for controls and 59.26 N/cm(2) for the rhGH group at 14 days and 25.99 N/cm(2) and 29.69 N/cm(2) for the control and the test group, respectively, at 42 days. Scanning electron microscope analysis showed more uniform and abundant bone tissue in contact with the implants for the test group at 14 days, and no differences between groups at 42 days. Furthermore, histologic analysis also showed accelerated bone repair in 14 days and a more advanced stage of bone remodeling for the rhGH-treated group when compared to controls after 42 days of repair. Such results show that the topical use of rhGH induces new bone formation in the early stages of bone repair and hence accelerates osseointegration of titanium dental implants.


Assuntos
Implantes Dentários , Hormônio do Crescimento Humano , Osseointegração , Animais , Remodelação Óssea , Coelhos , Distribuição Aleatória , Propriedades de Superfície , Tíbia , Titânio
10.
J Biomed Mater Res A ; 102(1): 30-6, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23568748

RESUMO

The aim of this study was to evaluate in vivo the influence of the native oxide layer on osseointegration and new bone formation on the surface of atmospheric plasma-sprayed porous titanium coatings. Porous titanium coatings were deposited on all implant surfaces, and half of the samples were subsequently submitted to oxide layer removal treatment. Samples were implanted onto the cortical bone of sheep (tibia) and evaluated at 30 and 60 days. Implants were removed en bloc and the attachment of bone to implants was examined by tensile pull-out test (osseointegration assessment), light microscopy, scanning electron microscopy (histological analysis), and instrumented hardness tests (mechanical properties of mature and newly formed bone tissue). Coatings submitted to oxide layer treatment presented higher osseointegration values at both healing periods and showed more mature and mineralized bone tissue when compared with nontreated coatings. Our findings showed that the use of acid-etching in association with atmospheric plasma spraying techniques improves osseointegration of titanium implants.


Assuntos
Materiais Revestidos Biocompatíveis/química , Implantes Experimentais , Osseointegração , Gases em Plasma/química , Titânio/química , Animais , Feminino , Ovinos , Propriedades de Superfície
11.
Implant Dent ; 22(4): 356-9, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23736311

RESUMO

PURPOSE: The aim of this study was to promote the immobilization of a bone activity biomodulator (diphosphonate) on titanium, commonly used in implant dentistry, to provide a local method of delivering this drug during the osseointegration process. METHODS: The implant material used in this study was commercially wrought titanium (Ticp), 99.9 mass%, grade II. From this material, discs of 15 mm diameter and 1 mm thick were fabricated. These discs underwent 3 sequential surface modification processes: (a) acid-etching, (b) hydroxyapatite coating, and (c) immersion in disodium pamidronate solution. Scanning electron microscopy, X-ray fluorescence, and X-ray diffraction analyses were carried out to characterize the surface created. RESULTS: The results of these analyses demonstrate that the acid-etching process, followed by the sintering of hydroxyapatite particles and immersion in a solution of disodium pamidronate were effective for diphosphonate immobilization on the titanium surface. CONCLUSIONS: The methodology used in this study allows us to conclude that immersion of hydroxyapatite-coated titanium in a solution of diphosphonate was efficient to promote the immobilization of this drug on the titanium surface.


Assuntos
Conservadores da Densidade Óssea/química , Materiais Revestidos Biocompatíveis/química , Materiais Dentários/química , Difosfonatos/química , Durapatita/química , Titânio/química , Condicionamento Ácido do Dente/métodos , Cristalografia , Sistemas de Liberação de Medicamentos , Humanos , Ácido Fluorídrico/química , Teste de Materiais , Microscopia Eletrônica de Varredura , Ácido Nítrico/química , Osseointegração/fisiologia , Pamidronato , Espectrometria por Raios X , Propriedades de Superfície , Difração de Raios X
12.
Med. oral patol. oral cir. bucal (Internet) ; 17(1): 102-107, ene. 2012. tab, ilus
Artigo em Inglês | IBECS | ID: ibc-98925

RESUMO

Objectives: To investigate the quality of newly formed bone in sheep mandibles submitted to distraction osteogenesis and low-level laser therapy (LLLT), based on hardness and modulus of elasticity values. The ideal moment for laser application (during the latency/activation period vs. during the bone consolidation period) was also evaluated. Computed tomography imaging was used to assess relapse as a result of early device removal. Study design: Extraoral distraction devices were placed in five sheep so as to achieve 1.5 cm of lengthened bone in 60 days. Distraction devices were removed 50, 40, and 33 days after surgery. Four animals were treated with LLLT, at different times, and one was used as control (no LLLT).Results: When applied during the bone consolidation period, LLLT caused an increase in hardness and modulus of elasticity values. On the other hand, animals irradiated with LLLT during the latency/activation period presented adelay in bone healing. A period of consolidation of 13 days (early device removal) was associated with relapse. Conclusions: Nanoindentation tests were able to detect slight abnormalities in bone metabolism and proved to be important tools for the assessment of bone quality following distraction osteogenesis. LLLT provided increased benefits when applied during the bone consolidation period, once it promoted an increase in hardness and modulus of elasticity values. According to our results, the bone consolidation period should be of at least 3 weeks, so as to prevent relapse (AU)


Assuntos
Animais , Osteogênese por Distração/métodos , Terapia com Luz de Baixa Intensidade/métodos , Módulo de Elasticidade , Análise do Estresse Dentário , Ovinos/fisiologia , Resultado do Tratamento , Recuperação de Função Fisiológica
13.
Med Oral Patol Oral Cir Bucal ; 17(1): e102-7, 2012 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-21743401

RESUMO

OBJECTIVES: To investigate the quality of newly formed bone in sheep mandibles submitted to distraction osteogenesis and low-level laser therapy (LLLT), based on hardness and modulus of elasticity values. The ideal moment for laser application (during the latency/activation period vs. during the bone consolidation period) was also evaluated. Computed tomography imaging was used to assess relapse as a result of early device removal. STUDY DESIGN: Extraoral distraction devices were placed in five sheep so as to achieve 1.5 cm of lengthened bone in 60 days. Distraction devices were removed 50, 40, and 33 days after surgery. Four animals were treated with LLLT, at different times, and one was used as control (no LLLT). RESULTS: When applied during the bone consolidation period, LLLT caused an increase in hardness and modulus of elasticity values. On the other hand, animals irradiated with LLLT during the latency/activation period presented a delay in bone healing. A period of consolidation of 13 days (early device removal) was associated with relapse. CONCLUSIONS: Nanoindentation tests were able to detect slight abnormalities in bone metabolism and proved to be important tools for the assessment of bone quality following distraction osteogenesis. LLLT provided increased benefits when applied during the bone consolidation period, once it promoted an increase in hardness and modulus of elasticity values. According to our results, the bone consolidation period should be of at least 3 weeks, so as to prevent relapse.


Assuntos
Terapia com Luz de Baixa Intensidade , Mandíbula/efeitos da radiação , Mandíbula/cirurgia , Osteogênese por Distração , Animais , Módulo de Elasticidade , Feminino , Testes de Dureza , Mandíbula/fisiologia , Carneiro Doméstico
14.
Stomatologija ; 14(4): 126-30, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23455982

RESUMO

The purpose of this study was to evaluate the mechanical behavior of three composites with nanoparticles Filtek Z350 XT (3M ESPE), Esthet X (Dentsply), Grandio (Voco) in enamel and body shades (A2) trough nanohardness, elastic modulus, compressive strength test, flexural strength test, diametral tensile strength, flexural modulus, weight filler content and Knoop microhardness. One sample of each material was submitted to nanohardness and elastic modulus. Five values of ten indentations were considered valids inside confidence intereval. Ten samples of each material were submitted to compressive strength, flexural strength and diametral tensile strength test at universal testing machine. The flexural modulus test was calculated based on flexural strength results. Ten samples of each group were submitted to knoop microhardness test. The results were submitted to ANOVA and Tukey statistical tests. The highest inorganic weight filler content for Grandio was registered after the organic mould decomposition. After statistical analysis Grandio showed the highest averages for nanohardness, elastic modulus, flexural modulus and knoop microhardness. For diametral tensile strength Grandio and Filtek Z350 XT obtained the highest averages. The tested composite resins ranged similar medias statistically for compressive strength. For flexural strength Filtek Z350 XT and Esthet X showed the highest averages. The results suggest that the weight filler content, the filler size and shape and the contact surface between nanofillers and organic phase has direct relation with composite resins with nanoparticles mechanical properties. Further studies should be carried out to improve the knowledge of composites with nanoparticles mechanical behavior.


Assuntos
Resinas Compostas/química , Nanocompostos/química , Análise do Estresse Dentário , Teste de Materiais , Fenômenos Mecânicos
15.
J Craniofac Surg ; 21(2): 513-5, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20216445

RESUMO

OBJECTIVE: The aim of the current study was to compare self-drilling and self-tapping screws with regard to bone contact and the production of bone debris using scanning electron microscopy. MATERIALS AND METHODS: Three New Zealand rabbit calvariae were used. Self-tapping and self-drilling screws were inserted into the outer surface of the skull with and without saline solution irrigation. All screws were 5 mm in length and were inserted until their tips projected through the endosteal side. Sixteen screws were used--8 with a head diameter of 1.5 mm and 8 with 2.0 mm. All self-tapping screws were inserted through a drill bit hole (1.6 mm for 2.0-mm screws and 1.3 mm for 1.5-mm screws). RESULTS: There was no damage to the screws after insertion. Bone damage occurred when irrigation was not used during the installment of the self-tapping screws. Bone debris formed during the installment of the self-drilling screws, which is considered beneficial. CONCLUSIONS: Because the insertion of self-drilling screws is performed with manual pressure, irrigation is not essential. Unlike the drilling that occurs with self-tapping screw, the bone debris formed with self-drilling screws is not the result of the heat generated, but rather the result of biologically active bone tissue capable of reacting with the screw and improving its performance. The animal model used proved highly appropriate for comparisons with human beings because the bone structures of the head have the same density and thickness.


Assuntos
Parafusos Ósseos , Osso Occipital/cirurgia , Animais , Materiais Biocompatíveis , Placas Ósseas , Craniotomia/métodos , Desenho de Equipamento , Fricção , Temperatura Alta , Processamento de Imagem Assistida por Computador , Teste de Materiais , Microscopia Eletrônica de Varredura , Modelos Animais , Osso Occipital/ultraestrutura , Pressão , Coelhos , Cloreto de Sódio , Propriedades de Superfície , Irrigação Terapêutica , Titânio
16.
Photomed Laser Surg ; 28(3): 365-9, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19860572

RESUMO

OBJECTIVE: This study evaluated the effect of low-level infrared laser on removal torque values of implants with poor initial stability inserted in rabbit tibias. BACKGROUND DATA: It is important to analyze the effects of laser radiation on bone repair when low-quality bone and implants with poor initial stability are used. MATERIALS AND METHODS: Thirty male white New Zealand rabbits (Oryctolagus Cuniculus) about 2 mo old and weighing 1.5-2.0 kg were used. Machined implants with poor initial stability were inserted in the tibia of each animal. Animals were randomly divided into two groups: laser irradiated and laser nonirradiated. Each group was further divided into three subgroups, according to the day the animals were killed: 15, 30, or 45 d. Torque values were measured with an axial digital torquemeter that applied counter-torque. The Student's t-test was used to calculate means and standard deviations for the comparisons between laser and control groups. RESULTS: A significant increase (p = 0.050) in removal torque values was found in the group of laser-irradiated implants at 15 and 30 d when compared with the control groups. At 45 d, no significant differences were found. CONCLUSION: In this study, low-level laser therapy promoted the osseointegration of implants with poor initial stability, particularly in the initial stages of bone healing.


Assuntos
Implantação Dentária Endóssea , Terapia com Luz de Baixa Intensidade , Osseointegração/efeitos da radiação , Animais , Osso e Ossos/efeitos da radiação , Corrosão Dentária , Remoção de Dispositivo , Masculino , Teste de Materiais/métodos , Coelhos , Propriedades de Superfície , Tíbia/cirurgia , Fatores de Tempo , Titânio , Torque
17.
Lasers Med Sci ; 25(2): 213-9, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19548055

RESUMO

This study evaluated the effect of low-level laser therapy (LLLT) on the chemical composition, crystallinity and crystalline structure of bone at the site of distraction osteogenesis. Five rabbits were subjected to distraction osteogenesis (latency = 3 days; rate and frequency = 0.7 mm/day for 7 days; consolidation = 10 days), and three were given LLLT with arsenide-gallium-aluminum (AsGaAl; 830 nm, 40 mW): 10 J/cm(2) dose per spot, applied directly to the distraction osteogenesis site during the consolidation stage at 48 h intervals. Samples were harvested at the end of the consolidation stage. X-ray fluorescence and X-ray diffraction were used to analyze chemical composition, crystallinity and crystalline structure of bone at the distraction osteogenesis site. The analysis of chemical composition and calcium (Ca) and phosphorus (P) ratios revealed greater mineralization in the LLLT group. Diffractograms showed that the crystalline structure of the samples was similar to that of hydroxyapatites. Crystallinity percentages were greater in rabbits that were given LLLT. Crystallinity (41.14% to 54.57%) and the chemical composition of the bone at the distraction osteogenesis site were similar to the that of the control group (42.37% to 49.29%). The results showed that LLLT had a positive effect on the biomodulation of newly formed bone.


Assuntos
Regeneração Óssea/efeitos da radiação , Terapia com Luz de Baixa Intensidade , Osteogênese por Distração , Osteogênese/efeitos da radiação , Animais , Osso e Ossos/química , Osso e Ossos/efeitos da radiação , Cálcio/análise , Masculino , Fósforo/análise , Coelhos , Espectrometria por Raios X , Difração de Raios X
19.
J Nanosci Nanotechnol ; 9(6): 3891-7, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19504937

RESUMO

A new, low cost, pulsed-DC plasma-enhanced chemical vapor deposition system that uses a bipolar, pulsed power supply was designed and tested to evaluate its capacity to produce quality diamond-like carbon films on the inner surface of steel tubes. The main focus of the study was to attain films with low friction coefficients, low total stress, a high degree of hardness, and very good adherence to the inner surface of long metallic tubes at a reasonable growth rate. In order to enhance the diamond-like carbon coating adhesion to metallic surfaces, four steps were used: (1) argon ion sputtering; (2) plasma nitriding; (3) a thin amorphous silicon interlayer deposition, using silane as the precursor gas; and (4) diamond-like carbon film deposition using methane atmosphere. This paper presents various test results as functions of the methane gas pressure and of the coaxial metal anode diameter, where the pulsed-DC voltage constant is kept constant. The influence of the coaxial metal anode diameter and of the methane gas pressure is also demonstrated. The results obtained showed the possibilities of using these DLC coatings for reduced friction and to harden inner surface of the steel tubes.

20.
Rev. bras. eng. biomed ; 24(3): 183-192, dez. 2008. ilus, graf
Artigo em Português | LILACS | ID: lil-548019

RESUMO

O objetivo deste estudo foi determinar a viabilidade de produção de uma prótese femoral de titânio garantindo a qualidade da matéria prima e as características das superfícies. Um protótipo foi criado pelo Método de Elementos Finitos em AutoCad® 2000. A simulação dos esforços demonstrou uma tensão de von Mises 8,1 vezes menor que a tensão crítica para escoamento do material. Na determinação dos constituintes metálicos, obteve-se: Fe  =   0,06%, Al  = 6,20%, V  = 3,57%, O  = 0,115%, N  = 0,003%, H  = 0,010%, e ausência de metais pesados. As propriedades elasto-plásticas da amostra tiveram valor médio de dureza de 4,45 (3,92 a 4,79) GPa e o módulo de elasticidade variou de 112,12 a 140,77  GPa (média  = 134,33). O coeficiente de rugosidade médio (DP) no cone foi de 0,60  (0,03) μm; na região jateada de 12,2 (0,8) μm e na ponta de 0,41 (0,01) μm. Nos ensaios de fadiga e de corrosão não foram observadas alterações. A análisegranulométrica do pó do material depositado demonstrou predominância de partículas médias (75  μm a 180  μm; 84%). A espessura da camada do material depositado apresentou valor médio de 52,7  μm (0 a 318  μm), porosidade média de 16% (variandode 3% a 41%), poros de diâmetro médio de 88,5  μm e profundidade média de 28,2  μm. A tensão (força por unidade de área) de adesão da camada porosa depositada revelou valoresde 15 a 17  MPa. Em conclusão, os resultados dos testes e ensaios técnicos estão dentro das normas internacionalmente recomendadas e padronizadas para implantes metálicos em titânio estando essa prótese de acordo com os padrões internacionaisde qualidade e segurança.


The objective of this work was to study the feasibility of manufacturing a cementless femoral prosthesis in Brazil, in compliance with internationalstandards of quality assurance. A virtual prototype by the Finite Elements Model in AutoCad® 2000 was assessed and demonstrated a von Mises tension 8.1 below the deformation point. In determining the metallic components, the percentages were Fe  = 0.06%, Al  = 6.20%, V  = 3.57%, O  = 0.115%, N  = 0.003%, H  = 0.010% without any contamination due to heavy metals. The elasto-plastic properties showed an average value of hardness of 4.45 (3.92 to 4.79) GPa and elasticity module varied from 112.12 to 140.77  GPa (mean  = 134.33). The average coefficient of roughness (SD) in the cone was 0.60 (0.03) μm, 12.2 (0.8) μm in the plasma spray coating region, and 0.41 (0.01) μm in the tip. In the assays for fatigue and corrosion no changes were observed. The grain size analysis of the deposited material dust demonstrated predominantly (84%) medium size particles (75  μm to 180  μm). The thickness of the deposited material layer presented average value of 52.7  μm (0 to 318  μm), average porosity of 16% (varying from 3% to 41%) and pores of average diameterof 88.5  μm and average depth of 28.2  μm. The force of adhesion of the deposited porous layer showed values between 15  and  17  MPa. Results were in accordance with the norms and tests internationally recommended and standardized for metallic implants in titanium alloy and  the femoral prosthesis manufactured with national technology was in accordance with international standards of design, quality and safeness.


Assuntos
Próteses e Implantes , Artroplastia de Quadril/tendências , Teste de Materiais/instrumentação , Teste de Materiais/métodos , Fenômenos Biomecânicos/métodos , Controle de Qualidade , Fêmur , Materiais Biocompatíveis/uso terapêutico , Tecnologia Biomédica/tendências , Titânio/uso terapêutico
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