ß-TCP/S53P4 Scaffolds Obtained by Gel Casting: Synthesis, Properties, and Biomedical Applications.

The objective of this study was to investigate the osteogenic and antimicrobial effect of bioactive glass S53P4 incorporated into ß-tricalcium phosphate (ß-TCP) scaffolds in vitro and the bone neoformation in vivo. ß-TCP and ß-TCP/S53P4 scaffolds were prepared by the gel casting method. Samples were morphologically and physically characterized through X-ray diffraction (XRD) and scanning electron microscope (SEM). In vitro tests were performed using MG63 cells. American Type Culture Collection reference strains were used to determine the scaffold's antimicrobial potential. Defects were created in the tibia of New Zealand rabbits and filled with experimental scaffolds. The incorporation of S53P4 bioglass promotes significant changes in the crystalline phases formed and in the morphology of the surface of the scaffolds. The ß-TCP/S53P4 scaffolds did not demonstrate an in vitro cytotoxic effect, presented similar alkaline phosphatase activity, and induced a significantly higher protein amount when compared to ß-TCP. The expression of Itg ß1 in the ß-TCP scaffold was higher than in the ß-TCP/S53P4, and there was higher expression of Col-1 in the ß-TCP/S53P4 group. Higher bone formation and antimicrobial activity were observed in the ß-TCP/S53P4 group. The results confirm the osteogenic capacity of ß-TCP ceramics and suggest that, after bioactive glass S53P4 incorporation, it can prevent microbial infections, demonstrating to be an excellent biomaterial for application in bone tissue engineering.

Argon plasma application on the surface of titanium implants: osseointegration study / Aplicação de plasma de argônio na superfície de implantes de titânio: estudo de osseointegração

Introduction: The development of new biomaterials with improved properties is a trend in regenerative medicine. The successful healing of implants is related to their osseointegration and the topographic geometry of their surface. Treatment with argon plasma acts on the surface of the implants, bringing several benefits to their osseointegration in the body. Material and Methods: Previously the in vivo study, the topography implants were observed by scanning electron microscopy (SEM). Following the implants were inserted in 14 male rats, and one perforation was made in the right and left tibias for implant placement without the surface treatment (control group), and with the argon plasma surface treatment (experimental group), respectively. The rats were euthanized at 4 weeks, a time in which tibia fragments were submitted for histological and histomorphometric examination, and torque removal test for comparison and analysis of osseointegration. Results: The SEM images showed the argon plasma surface treatment altered the topography. At the end of the study, both greater bone formation and better osseointegration were verified in the experimental group, and a statistically significant difference between the groups was observed. Conclusion: It was concluded that implants with this surface treatment can bring more practicality in the rehabilitation treatment, and more comfort in the patients' postoperative time (AU)

Introdução: O desenvolvimento de novos biomateriais com propriedades aprimoradas é uma tendência na medicina regenerativa. A cicatrização bem-sucedida dos implantes está relacionada à sua osseointegração e à geometria topográfica de sua superfície. O tratamento com plasma de argônio atua na superfície dos implantes, trazendo diversos benefícios para sua osseointegração no corpo. Materiais e Métodos: Antes do estudo in vivo, a topografia dos implantes foi observada por microscopia eletrônica de varredura (MEV). Em seguida, os implantes foram inseridos em 14 ratos machos, e uma perfuração foi feita nas tíbias direita e esquerda para a colocação do implante sem o tratamento de superfície (grupo controle) e com o tratamento de superfície de plasma de argônio (grupo experimental), respectivamente. Os ratos foram sacrificados após 4 semanas, momento em que fragmentos das tíbias foram submetidos a exame histológico e histomorfométrico, além do teste de remoção de torque para comparação e análise da osseointegração. Resultados: As imagens de MEV mostraram que o tratamento de superfície com plasma de argônio alterou a topografia. Ao final do estudo, foi verificada maior formação óssea e melhor osseointegração no grupo experimental, e foi observada diferença estatisticamente significativa entre os grupos. Conclusão: Concluiu-se que os implantes com esse tratamento de superfície podem trazer mais praticidade no tratamento de reabilitação e maior conforto no pós-operatório dos pacientes (AU)

Effect of radiotherapy on the differentiation and osteogenic activity of mesenchymal stem cells on dental implants / Efeito da radioterapia na diferenciação e atividade osteogênica de células-tronco mesenquimais em implantes dentários

Objective: to evaluate the differentiation and gene expression of transcripts related to osteogenesis in a primary culture of Mesenchymal Stem Cells (MSCs) derived from rat femurs submitted to radiotherapy and the installation of pure titanium implants. Material and Methods: fifty-four rats received titanium implants in both femurs and were divided into three groups: Control: implant surgery (C); Implant + immediate irradiation (IrI), and Implant + late irradiation (IrL). Euthanasia occurred 3, 14, and 49 days after surgery. The bone marrow MSCs from the femurs were isolated and cultivated. The cell viability, total protein content, alkaline phosphatase (ALP) activity, and the formation of mineralization nodules and cellular genotoxicity were analyzed. The gene expression of Alkaline Phosphatase (phoA), Collagen 1 (COL1), Runt-related transcription factor 2 (RUNX2), Osterix (OSX), Osteopontin (OPN), Integrin ß1(ITGB1), Bone Sialoprotein (BSP), Osteonectin (SPARC), Osteocalcin (Bglap), Transforming Growth Factor ß-type (TGF-ß), Granulocyte Macrophage Colony Stimulating Factor (GM-CSF), Interleukin-6 (IL-6), Apolipoprotein E (APOE) and Prostaglandin E2 synthase (PGE2) were evaluated by qRT- PCR. Results: ionizing radiation suppresses the gene expression of essential transcripts for bone regeneration, as well as cellular viability, as observed in the IrI and IrL groups. Conclusion: although this can lead to the loss of osseointegration and failure of the implant, the MSCs showed more activity at 49 days than at 3 and 14 days. (AU)

Objetivo: avaliar a diferenciação e expressão gênica de transcritos relacionados à osteogênese em cultura primária de MSCs derivadas de fêmures de ratos submetidos à radioterapia e instalação de implantes de titânio puro. Material e Métodos: cinquenta e quatro ratos receberam implantes de titânio em ambos os fêmures e foram divididos em três grupos: Controle: cirurgia de implante (C); Implante + irradiação imediata (IrI) e Implante + irradiação tardia (IrL). A eutanásia ocorreu 3, 14 e 49 dias após a cirurgia. As MSCs de medula óssea dos fêmures foram isoladas e cultivadas. Foram analisadas a viabilidade celular, teor de proteína total, atividade da fosfatase alcalina (ALP), formação de nódulos de mineralização e genotoxicidade celular. A expressão gênica de Fosfatase Alcalina (phoA), Colágeno 1 (COL1), fator de transcrição relacionado a Runt 2 (RUNX2), Osterix (OSX), Osteopontina (OPN), Integrina ß1 (ITGB1), Sialoproteína Óssea (BSP), Osteonectina (SPARC), Osteocalcina (Bglap), Fator de Crescimento Transformador tipo ß (TGF-ß), Fator Estimulante de Colônia de Granulócitos-Macrófagos (GM-CSF), Interleucina-6 (IL-6), Apolipoproteína E (APOE) e Prostaglandina E2 sintase (PGE2) foram avaliados por qRT-PCR. Resultados: a radiação ionizante suprime a expressão gênica de transcritos essenciais para a regeneração óssea, bem como a viabilidade celular, como observado nos grupos IrI e IrL. Conclusão:embora isso possa levar à perda da osseointegração e falha do implante, as MSCs apresentaram maior atividade aos 49 dias do que aos 3 e 14 dias (AU)

Influence of titanium nanotubular surfaces, produced by anodization, on the behavior of osteogenic cells: in vitro evaluation / Influência da superfície nanotubular do titânio, produzido por anodização, no comportamento de células osteogênicas: avaliação in vitro

Objective: The objective of this study was to evaluate in vitro the influence of the anodized surface of Ti35Nb7Zr alloy on the behavior of osteogenic cells, for future application in biomedical implants. Material and Methods: For the development of this research, samples of commercially pure titanium (TiCp) and samples of Ti35Nb7Zr alloy were anodized, both were characterized by scanning electron microscopy (SEM) and were plated afterwards with human osteoblast-like cells (MG63 line) (2 x 104). Cell adhesion, cytotoxicity test, formation of mineralization nodules and a comet assay were also performed in different periods. The bottom of the plate was used as a control, without a sample. Results: SEM analysis showed that the topography of both samples presented surfaces covered by nanotubes. Cellular morphology exhibited spreading in both samples proposing an intimate cell- material liaison. After 3 days, the Ti35Nb7Zr group exhibited greater cell viability than the TiCp group (p<0.01). Regarding calcium content, there was no statistical difference between the anodized groups, but there was a difference between the experimental groups and the control group (p<0.01). In the comet assay, the percentage of DNA in the comet tail did not exhibit any significant difference (p>0.05) among the groups in the evaluated periods. Conclusion: It was concluded that this process of anodization was efficient to form nanotubes, as well as promote a positive influence on the behavior of osteogenic cells without promoting cell damage. (AU)

Objetivo: O objetivo deste estudo foi avaliar in vitro a influência da superfície anodizada da liga Ti35Nb7Zr no comportamento de células osteogênicas, para futura aplicação em implantes biomédicos. Material e Métodos: Para o desenvolvimento desta pesquisa, amostras de titânio comercialmente puro (TiCp) e amostras da liga Ti35Nb7Zr foram anodizadas, ambas foram caracterizadas por microscopia eletrônica de varredura (MEV) e posteriormente plaqueadas com células semelhantes a osteoblastos humanos (linha MG63) (2 x 104). Foram realizados em diferentes períodos a adesão celular, teste de citotoxicidade, formação de nódulos de mineralização e ensaio do cometa. O fundo da placa foi usado como controle, sem amostra. Resultados: A análise em MEV mostrou que a topografia de ambas as amostras apresentava superfícies cobertas por nanotubos. A morfologia celular exibiu espalhamento em ambas as amostras, propondo uma ligação íntima célula-material. Após 3 dias, o grupo Ti35Nb7Zr exibiu maior viabilidade celular do que o grupo TiCp (p<0.01). Em relação ao teor de cálcio, não houve diferença estatística entre os grupos anodizados, mas houve diferença entre os grupos experimentais e o grupo controle (p<0.01). No ensaio do cometa, a porcentagem de DNA na cauda do cometa não apresentou diferença significativa (p> 0.05) entre os grupos nos períodos avaliados. Conclusão:Concluiu-se que esse processo de anodização foi eficiente para formar nanotubos, além de promover uma influência positiva no comportamento das células osteogênicas sem promover dano celular. (AU)

Bioactivity of an Experimental Dental Implant with Anodized Surface.

BACKGROUND: Several studies proved that anodic oxidation improves osseointegration. This study aimed to optimize osseointegration through anodization in dental implants, obtaining anatase phase and controlled nanotopography. METHODS: The division of the groups with 60 titanium implants was: control (CG); sandblasted (SG); anodized (AG): anodized pulsed current (duty cycle 30%, 30 V, 0.2 A and 1000 Hz). Before surgery, surface characterization was performed using Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), X-ray Dispersive Energy Spectroscopy (EDS) and Raman Spectroscopy. For in vivo tests, 10 New Zealand white rabbits received an implant from each group. The sacrifice period was 2 and 6 weeks (n = 5) and the specimens were subjected to computed microtomography (µCT) and reverse torque test. RESULTS: AFM and SEM demonstrated a particular nanotopography on the surface in AG; the anatase phase was proved by Raman spectroscopy. In the µCT and in the reverse torque test, the AG group presented better results than the other groups. CONCLUSION: The chemical composition and structure of the TiO2 film were positively affected by the anodizing technique, intensifying the biological characteristics in osseointegration.

Effect of DLC Films with and without Silver Nanoparticles Deposited On Titanium Alloy.

Diamond-like carbon (DLC) film is a biocompatible hard coating material that can prevent the leaching of metal ions. This study evaluates the structural characteristics of DLC, with and without silver nanoparticles, deposited by plasma (PECVD) on titanium alloy (Ti-6Al-4V) and bone formation in contact with DLC films. Sixty Ti-6Al-4V samples were used divided in: uncoated, coated with DLC and coated with DLC-Ag. After structural characterization, samples were fixed bilaterally at the rabbit's mandible. After 15 and 90 days, samples were characterized again and bone formation in the area was analyzed by histomorphometry. Statistical analysis was performed by two-way ANOVA. Both the DLC and DLC-Ag films were firmly adhered and showed a high electrical resistance without significant changes in the Raman spectrum after in vivo integration. After 15 days, there were immature bone trabeculae in the interface and partially covering the surface. After 90 days, mature bone filled the interface and coved the surface. There was no statistically significant difference among the three groups in both periods. In conclusion, osseointegration with DLC, DLC-Ag and uncoated Ti-6Al-4V is similar. However, DLC and DLC-Ag coverings have the advantage of electrical insulation and can presumably control bacterial activity and ion leaching.

Sitagliptin's effects on bone tissue and osseointegration in diabetic rats.

OBJECTIVE: To investigate the effects of sitagliptin, a dipeptidyl peptidase 4 inhibitor used to treat type II diabetes, on bone tissue and on implant osseointegration in diabetic rats. DESIGN: Thirty-two male rats were divided into four groups: 1) Diabetic animals (GD); 2) Diabetic animals that received sitagliptin (GDS); 3) Normoglycemic animals (GN); and 4) Normoglycemic animals that received sitagliptin (GNS). All animals received titanium implants in the right tibia. Sitagliptin or water were administered for 4 weeks. Glycemia, HOMA-IR, insulinemia, microtomographic parameters of the left tibia and implant bone area fraction occupancy (BAFO) of the right tibia were evaluated. RESULTS: The model used to induce diabetes led to hyperglycemia. However, HOMA-IR results showed no insulin resistance, and insulinemia was lower in diabetic animals, demonstrating the development of type I diabetes. Sitagliptin administration did not influence glycemic control. The diabetic animals showed a lower BAFO and bone volume fraction, as well as a lower trabecular number and thickness, revealing the deleterious effect of diabetes on bone metabolism and osseointegration. CONCLUSION: In this model, sitagliptin administration did not reverse the negative effects of type I diabetes on bone, suggesting that sitagliptin has no direct action on bone tissue and has no protective bone action in decompensated diabetic animals.

Total protein level reduction of odontopathogens biofilms by Rosmarinus officinalis L. (rosemary) extract: an analysis on Candida albicans and Streptococcus mutans / Redução do nível de proteína total de biofilmes de odontopatógenos por extrato de Rosmarinus officinalis L. (alecrim): uma análise sobre Candida albicans e Streptococcus mutans

Objective: The resistance of fungi and bacteria to the available antimicrobials has increased and the development of alternative products to control them has become a very requirement. The use of plant products could be a viable option due to the efficacy, viability, and availability they present. Thereby, this study evaluated the effect of R. officinalis L. extract on C. albicans and S. mutans biofilms, by the total protein level analysis presented by the microorganisms. Material and Methods: For this purpose, monomicrobial biofilms were formed for 48 h and exposed to the R. officinalis L. extract for 5 min. Then, total protein quantification was performed by Lowry method. Results: The analysis showed significant total protein reduction of the biofilms after exposure to the plant extract, with 39 ± 11%, for C. albicans, and 32 ± 11%, for S. mutans. Conclusion: R. officinalis L. extract decreased the total protein level in both biofilms. Thus, C. albicans and S. mutans protein composition could be a target for action of antimicrobial agents. (AU)

Objetivo: A resistência de fungos e bactérias aos antimicrobianos disponíveis tem se elevado e o desenvolvimento de produtos alternativos para controlar micróbios tem se tornado uma necessidade real. A utilização de produtos de origem vegetal poderia ser uma opção viável, devido à eficácia, viabilidade e disponibilidade que apresentam. Sendo assim, este estudo avaliou o efeito do extrato de R. officinalis L. (alecrim) sobre biofilmes de C. albicans and S. mutans, analisando o nível de proteína total apresentada pelos micro-organismos. Material e Métodos: Para tanto, biofilmes monomicrobianos foram formados por 48 h e expostos ao extrato de R. officinalis L. por 5 min. Então, a quantificação de proteína total foi realizada por método de Lowry. Resultados: A análise demonstrou reduções significativas de proteína total de cada biofilme após exposição ao extrato, sendo 39 ± 11% no biofilme de C. albicans e 32 ± 11%, no caso de S. mutans. Conclusão: O extrato de R. officinalis L. diminuiu o nível de proteína total em ambos os biofilmes. Com isso, a composição proteica de C. albicans e S. mutans poderia ser um alvo para ação de agentes antimicrobianos. (AU)

CaP Coating and Low-Level Laser Therapy to Stimulate Early Bone Formation and Improve Fixation of Rough Threaded Implants.

PURPOSE: This study aimed to compare in vivo osteogenesis on rough threaded dental implants with and without calcium phosphate (CaP) coating deposition, alone or in association with low-level laser therapy (LLLT) by gallium aluminum arsenide. MATERIAL AND METHODS: Four groups were studied: G1: implant; G2: implant + CaP coating; G3: implant + LLLT; and G4: implant + CaP coating + LLLT. LLLT was applied for 7 days at the surgical site before and after placing the implant. Topographic characterization was performed before surgery using scanning electron microscopy and energy dispersion spectrophotometry. Bone-implant contact (BIC) was measured after 1, 2, and 6 weeks and reverse torque after 6 weeks. In short periods, G2, G3, and G4 showed significantly greater BIC than G1 (P < 0.05), but no difference in BIC was observed at 6 weeks. However, the values for the removal torque test at 6 weeks were higher in G2 and G4 (P < 0.05). CONCLUSION: Both CaP coating alone and using LLLT induce cellular stimulation and improve BIC in short-term healing, resulting in higher implant fixation, and should be considered in clinical practice due to their low cost and high effectiveness.

Influence of chronic alcoholism and estrogen deficiency on the immunohistochemical expression of regulatory proteins of the bone resorption process in the periodontium of Wistar rats.

OBJECTIVE: The aim of this study was to investigate possible changes in immunohistochemical expression of proteins regulating the bone resorption process in the periodontium of rats subjected to alcoholism and/or estrogen deficiency. The investigated proteins were receptor activator of nuclear factor-kappa ß ligand (RANKL), a protein that stimulates bone resorption, and osteoprotegerin (OPG), a protein that inhibits bone resorption. At the molecular level, decreased OPG expression and/or increased RANKL expression are consistent with a greater predisposition to bone resorption. DESIGN: Wistar female rats were divided into ovariectomized (ovx) and non-ovariectomized (sham) groups, and subdivided into ad libitum diet (free diet), alcoholic diet (20% solution), and isocaloric diet (diet with a similar amount of calories as compared with groups ingesting an alcoholic diet). The alveolar bone crest and adjacent tissues were evaluated by immunohistochemical analyses for detection of OPG and RANKL. RESULTS: A significant decrease in OPG expression and a significant increase in RANKL expression were observed in ovariectomized animals which received alcohol as compared with non-ovariectomized animals which received isocaloric diet (experimental control). When estrogen deficiency was evaluated independently of the diet type, a significant decrease in OPG expression and a significant increase in RANKL expression were observed in ovariectomized animals as compared with non-ovariectomized animals. CONCLUSIONS: Estrogen deficiency associated with alcoholic diet, as well as estrogen deficiency (analyzed independently of diet type), decreased the immunostaining for OPG and increased the immunostaining for RANKL in the periodontium of rats.

Expression of BMP II by human osteoblasts cultivated on dense or porous titanium / Expressão da BMP II por osteoblastos humanos cultivados sobre titânio denso ou poroso

Objective: Modifications of titanium have been described as an important tool improving bone repair and boneimplant contact. The aim of this research was to quantified the expression of the morphogenetic bone protein II (BMP II) produced by human cells with osteoblast differentiation, after cultured over dense or porous samples of pure titanium grade II. Material and Methods: The experimental groups were: control group, dense titanium, porosity of 33.79% and porosity of 41,79% (n=36). The samples were produced by powder metallurgy technique. Mesenquimal steam cells isolated from alveolar bone of healthy donors were stimulated to differentiate, assuming an osteoblastic phenotype, by supplemented medium and plated over the samples. After 7 and 14 days, the RNA was collected to perform reverse transcriptase polymerase chain reaction (RT-PCR) in real time. Data was analysed by t-Student and ANOVA tests. The porosity, the pore morphology and interconnection were evaluated by Scanning Electron Microscopy (SEM). Results: Total porosity (obtained after apply dimensions and density formulas) and surface porosity (SEM) presented significant differencesamong the groups. For the group of total porosity of 33.79%, the superficial porosity was 32.5% (± 7.74%) and for the group of 41.79%, the superficial porosity was 37.4% (± 7.95%), significantly lower. The expression of BMP II was similar in all groups. Conclusion: The present study demonstrated that powder metallurgy has a reduced ability to standardize the porosity in the samples and that the porosity does not interfere in the cellular response of BMP II production, an important inducer of osteoblastic differentiation. (AU)

Objetivo: As modificações do titânio são descritas como importantes ferramentas na melhora do reparo ósseo no contato osso implante. O objetivo deste estudo foi quantificar a expressão da proteína óssea morfogênica II (BMP II) por células humanas com diferenciação osteoblastica, quando cultivadas sobre amostras de titânio puro grau II, denso ou poroso. Material e Métodos: Os grupos experimentais foram: controle, titânio denso, titânio de maior porosidade e titânio de menor porosidade, sendo que, as amostras foram confeccionadas pela técnica da metalurgia do pó. As células isoladas de doadores saudáveis foram plaqueadas sobre as amostras. Após 7 e 14 dias, o RNA foi extraído das células. A qualidade e integridade do RNA foram analisadas qualitativamente por eletroforese e quantitativamente por espectrofotômetro. O cDNA foi confeccionado e a foi utilizada técnica de reação em cadeia da polimerase (PCR) em tempo real. Os dados foram utilizados para quantificação relativa, e o gene constitutivo foi a BetaActina. A morfologia e a interligação dos poros foram comprovadas por Microscopia Eletrônica de Varredura (MEV). Resultados: A porosidade superficial (MEV) teve diferença significativa em relação a porosidade obtida analisando-se volume e massa das amostras. Para o grupo 3,79%, a superficial foi de 32,5% (±7,74%) e para o grupo 41,79% a porosidade superficial foi de 37,4% (±7,95%), significativamente menor. A expressão da BMP II foi semelhante em todos os grupos. Conclusão: Concluiu-se a metalurgia do pó tem reduzida capacidade de padronização da porosidade das amostras por ela confeccionas e que a porosidade não interfere na resposta celular de produção da BMP II, importante indutor de diferenciação osteoblastica.(AU)

PDLLA honeycomb-like scaffolds with a high loading of superhydrophilic graphene/multi-walled carbon nanotubes promote osteoblast in vitro functions and guided in vivo bone regeneration.

Herein, we developed honeycomb-like scaffolds by combining poly (d, l-lactic acid) (PDLLA) with a high amount of graphene/multi-walled carbon nanotube oxides (MWCNTO-GO, 50% w/w). From pristine multi-walled carbon nanotubes (MWCNT) powders, we produced MWCNTO-GO via oxygen plasma etching (OPE), which promoted their exfoliation and oxidation. Initially, we evaluated PDLLA and PDLLA/MWCNTO-GO scaffolds for tensile strength tests, cell adhesion and cell viability (with osteoblast-like MG-63 cells), alkaline phosphatase (ALP, a marker of osteoblast differentiation) activity and mineralized nodule formation. In vivo tests were carried out using PDLLA and PDLLA/MWCNTO-GO scaffolds as fillers for critical defects in the tibia of rats. MWCNTO-GO loading was responsible for decreasing the tensile strength and elongation-at-break of PDLLA scaffolds, although the high mechanical performance observed (~600MPa) assures their application in bone tissue regeneration. In vitro results showed that the scaffolds were not cytotoxic and allowed for osteoblast-like cell interactions and the formation of mineralized matrix nodules. Furthermore, MG-63 cells grown on PDLLA/MWCNTO-GO significantly enhanced osteoblast ALP activity compared to controls (cells alone), while the PDLLA group showed similar ALP activity when compared to controls and PDLLA/MWCNTO-GO. Most impressively, in vivo tests suggested that compared to PDLLA scaffolds, PDLLA/MWCNTO-GO had a superior influence on bone cell activity, promoting greater new bone formation. In summary, the results of this study highlighted that this novel scaffold (MWCNTO-GO, 50% w/w) is a promising alternative for bone tissue regeneration and, thus, should be further studied.

Qualidade do reparo ósseo em ratas ovariectomizadas, lesionadas e tratadas com Arnica montana fitoterápica e homeopática / Quality of bone repair in ovariectomized rats with bone lesions treated with phytotherapic and homeopathic Arnica montana

Objetivo: Dados estatísticos nacionais e mundiais demonstram que o número de indivíduos idosos tende a crescer de maneira exponencial nos próximos anos, tornando-se uma população significativamente e proporcionalmente maior que as demais. Entre as doenças mais comuns nessa faixa estaria encontra-se a osteoporose, doença que reduz a massa esquelética e deteriora a microarquitetura do osso causando fragilidade e aumentando o risco de fraturas. Material e Métodos: Este estudo teve como proposta avaliar o efeito da Arnica montana fitoterápica e homeopática no reparo de lesões ósseas, visando uma possível forma de tratamento de fraturas na vigência da osteoporose. Os ensaios experimentais foram realizados em ratas Wistar adultas, divididas em quatro grupos: ovariectomizado tratado com Arnica montana 6CH homeopática (OVZ 6CH); ovariectomizado tratado com extrato fitoterápico de Arnica montana (OVZ TM); ovariectomizada tratado com placebo (OVZ PL) falsa cirurgia de ovariectomia e tratado com placebo (Sham PL). Após 45 dias da cirurgia sham ou de ovariectomia, foi realizada uma lesão óssea monocortical. Os animais foram eutanasiados após 6, 12, 18 e 28 dias e as tíbias retiradas para avaliação das suas dimensões e analise do reparo ósseo através de densidade óssea radiográfica, ensaios biomecânicos e microscopia eletrônica de varredura (MEV). Os dados do teste de flexão foram submetidos à analise estatística pelos testes de ANOVA e Tukey (p< 5%). Resultados: Conclui-se que o tratamento com arnica 6CH foi melhor que o com arnica TM quanto à resistência e à qualidade de regeneração óssea, enquanto a TM mostrou melhor valor de densidade óptica. Conclusão: Esse estudo concluiu que o tratamento com Arnica montana homeopática foi mais eficiente que com Arnica fitoterápica na regeneração óssea de ratas com osteoporose (AU)

Objective: National and international data show that in the next years the elder population tends to have an exponential increase becoming to be significantly higher than other ages. Among the frequent diseases in the elderly, osteoporosis is a disease that decreases bone mass and deteriorates bone structure causing fragility and a high risk of fracture. This study aimed to evaluate the effect of phytotherapic and homeopathic Arnica montana on bone repair quality and its possible use in the treatment of bone fracture in patients with osteoporosis. Material and Methods: This experimental study was performed in Wistar adult female rats divided in 4 groups according to the following treatments: ovariectomized treated with homeopathic A. montana 6CH (OVZ 6CH); ovariectomized treated with phytotherapic A. montana (OVZ TM); ovariectomized with placebo (OVZ PL) and rats with sham surgery and placebo (Sham PL). In a period of 45 days after ovariectomy or sham surgery, all animals got a monocortical lesion. They were euthanized after 6, 12, 18 and 28 days and had the tibiae removed to evaluate dimensions and bone repair by radiographic density, biomechanical test and scanning electronic microscopy (SEM). Data were analyzed by ANOVA and TUKEY tests (p < 0.05). Results: Results showed that treatment with Arnica 6CH was better than Arnica TM considering bone resistance and bone repair quality. Conclusion: This study concluded that treatment with homeopathic A. montana was more efficient than with phytotherapic Arnica in bone regeneration in rats with osteoporosis.(AU)

Evaluation of dentists' knowledge of the use of oral exfoliative cytology in clinical practice.

Oral exfoliative cytology (EC) is a rapid and practical complementary test that can be used in the diagnosis of various diseases. The objectives of this study were to assess dentists' knowledge of EC and to disseminate information on the technique. The study included 240 dentists from the city of Anápolis (Goiás, Brazil) who answered a questionnaire regarding demographic data and data relating to EC and who then received information on the technique. The data revealed that 26.92% of the dentists did not know about EC. Among those who reported knowledge of EC, 33.91% did not know the procedures for performing the technique, and 85.38% had no experience with EC. In addition, 54.09% of the answers regarding the instrument used to collect the material and 56.82% of the answers concerning suitable fixatives were inappropriate. Although 73.02% of the dentists adequately identified the pathologies for which EC is recommended, it was concluded that the respondents had poor knowledge of EC. There is a need to increase dentists' awareness of this subject and of EC's use in diagnostic practices.

Effect of axial loads on implant-supported partial fixed prostheses by strain gauge analysis

OBJECTIVES: The present study used strain gauge analysis to perform an in vitro evaluation of the effect of axial loading on 3 elements of implant-supported partial fixed prostheses, varying the type of prosthetic cylinder and the loading points. MATERIAL AND METHODS: Three internal hexagon implants were linearly embedded in a polyurethane block. Microunit abutments were connected to the implants applying a torque of 20 Ncm, and prefabricated Co-Cr cylinders and plastic prosthetic cylinders were screwed onto the abutments, which received standard patterns cast in Co-Cr alloy (n=5). Four strain gauges (SG) were bonded onto the surface of the block tangentially to the implants, SG 01 mesially to implant 1, SG 02 and SG 03 mesially and distally to implant 2, respectively, and SG 04 distally to implant 3. Each metallic structure was screwed onto the abutments with a 10 Ncm torque and an axial load of 30 kg was applied at five predetermined points (A, B, C, D, E). The data obtained from the strain gauge analyses were analyzed statistically by RM ANOVA and Tukey's test, with a level of significance of p<0.05. RESULTS: There was a significant difference for the loading point (p=0.0001), with point B generating the smallest microdeformation (239.49 µε) and point D the highest (442.77 µε). No significant difference was found for the cylinder type (p=0.748). CONCLUSIONS: It was concluded that the type of cylinder did not affect in the magnitude of microdeformation, but the axial loading location influenced this magnitude.

Effect of axial loads on implant-supported partial fixed prostheses by strain gauge analysis.

OBJECTIVES: The present study used strain gauge analysis to perform an in vitro evaluation of the effect of axial loading on 3 elements of implant-supported partial fixed prostheses, varying the type of prosthetic cylinder and the loading points. MATERIAL AND METHODS: Three internal hexagon implants were linearly embedded in a polyurethane block. Microunit abutments were connected to the implants applying a torque of 20 Ncm, and prefabricated Co-Cr cylinders and plastic prosthetic cylinders were screwed onto the abutments, which received standard patterns cast in Co-Cr alloy (n=5). Four strain gauges (SG) were bonded onto the surface of the block tangentially to the implants, SG 01 mesially to implant 1, SG 02 and SG 03 mesially and distally to implant 2, respectively, and SG 04 distally to implant 3. Each metallic structure was screwed onto the abutments with a 10 Ncm torque and an axial load of 30 kg was applied at five predetermined points (A, B, C, D, E). The data obtained from the strain gauge analyses were analyzed statistically by RM ANOVA and Tukey's test, with a level of significance of p<0.05. RESULTS: There was a significant difference for the loading point (p=0.0001), with point B generating the smallest microdeformation (239.49 µÎµ) and point D the highest (442.77 µÎµ). No significant difference was found for the cylinder type (p=0.748). CONCLUSIONS: It was concluded that the type of cylinder did not affect in the magnitude of microdeformation, but the axial loading location influenced this magnitude.

Evaluation of bone ingrowth into porous titanium implant: histomorphometric analysis in rabbits.

A porous material for bone ingrowth with adequate pore structure and appropriate mechanical properties has long been sought as the ideal bone-implant interface. This study aimed to assess in vivo the influence of three types of porous titanium implant on the new bone ingrowth. The implants were produced by means of a powder metallurgy technique with different porosities and pore sizes: Group 1 = 30 % and 180 µm; Group 2 = 30% and 300 µm; and Group 3 = 40% and 180 µm;. Six rabbits received one implant of each type in the right and left tibiae and were sacrificed 8 weeks after surgery for histological and histomorphometric analyses. Histological analysis confirmed new bone in contact with the implant, formed in direction of pores. Histomorphometric evaluation demonstrated that the new bone formation was statistically significantly lower in the group G1 than in group G3, (P = 0.023). Based on these results, increased porosity and pore size were concluded to have a positive effect on the amount of bone ingrowth.

Evaluation of bone ingrowth into porous titanium implant: histomorphometric analysis in rabbits

A porous material for bone ingrowth with adequate pore structure and appropriate mechanical properties has long been sought as the ideal bone-implant interface. This study aimed to assess in vivo the influence of three types of porous titanium implant on the new bone ingrowth. The implants were produced by means of a powder metallurgy technique with different porosities and pore sizes: Group 1 = 30 percent and 180 µm; Group 2 = 30 percent and 300 µm; and Group 3 = 40 percent and 180 µm;. Six rabbits received one implant of each type in the right and left tibiae and were sacrificed 8 weeks after surgery for histological and histomorphometric analyses. Histological analysis confirmed new bone in contact with the implant, formed in direction of pores. Histomorphometric evaluation demonstrated that the new bone formation was statistically significantly lower in the group G1 than in group G3, (P = 0.023). Based on these results, increased porosity and pore size were concluded to have a positive effect on the amount of bone ingrowth.

Porous titanium for biomedical applications: An experimental study on rabbits

Objective: The aim of this study was to carry out an in vivo assessment of bone ingrowth in two different typesof porous titanium -the first being completely porous, and the second with a porous surface and dense nucleus,manufactured by powder metallurgy- and to evaluate their mechanical properties. Study design: Ten scaffoldsfrom each group were submitted to metallographic analysis and compression tests. Next, two scaffolds of eachtype were inserted into 14 rabbits, which were sacrificed 8 weeks after surgery. The samples were submitted forhistological examination. Results: Metallographic analysis revealed interconnected pores, and the average interconnectedpore diameter was about 360 mm, with 36% total porosity. The totally porous titanium samples and thetitanium samples with porous surface and dense nucleus showed an average compressive strength of 16.19 MPaand 69.27 MPa, respectively. After 8 weeks, the animals showed bone ingrowth, even into the most internal pores.Conclusions: The pore morphology was effective in permitting bone ingrowth in both groups. Titanium scaffoldswith a porous surface and dense nucleus showed the best mechanical properties and most adequate interface (AU)

Histomorphometric analysis of pure titanium implants with porous surface versus rough surface

The purpose of this study was to analyze the bone repair around commercially pure titanium implants with rough and porous surface, fabricated using powder metallurgy technique, after their insertion in tibiae of rabbits. Seven male rabbits were used. Each animal received 3 porous-surface implants in the left tibia and 3 rough-surface implants in the right tibia. The rabbits were sacrificed 4 weeks after surgery and fragments of the tibiae containing the implants were submitted to histological and histomorphometric analyses to evaluate new bone formation at the implant-bone interface. Means ( percent) of bone neoformation obtained in the histomorphometric analysis were compared by Student's t-test for paired samples at 5 percent significance level.. The results of the histological analysis showed that osseointegration occurred for both types of implants with similar quality of bone tissue. The histomorphometric analysis revealed means of new bone formation at implant-bone interface of 79.69 ± 1.00 percent and 65.05 ± 1.23 percent for the porous- and rough-surface implants, respectively. Statistically significant difference was observed between the two types of implants with respect to the amount new bone formation (p<0.05). In conclusion, the porous-surface implants contributed to the osseointegration because they provide a larger contact area at implant-bone interface.

O propósito deste estudo foi avaliar a reparação óssea ao redor de implantes de superfície porosa comparados com implantes de superfície rugosa, ambos confeccionados de titânio puro grau 2 por meio da técnica de metalurgia do pó. Os implantes foram inseridos em tíbias de coelhos. Foram utilizados neste estudo 7 coelhos machos, sendo que cada um recebeu 3 implantes de superfície porosa na tíbia esquerda e 3 implantes de superfície rugosa na tíbia direita. Os animais foram sacrificados 4 semanas após a cirurgia e os fragmentos das tíbias contendo os implantes foram submetidos à análise histológica e histomorfométrica, visando analisar a neoformação óssea na interface osso-implante. As médias ( por cento) obtidas na análise histomorfométrica foram avaliadas por meio do teste estatístico t-student de amostras pareadas com nível de significância de 5 por cento. Os resultados da análise histológica mostraram que a osseointegração foi obtida nos dois tipos de implantes com similar qualidade de tecido ósseo. Na análise histomorfométrica, verificaram-se médias de neoformação óssea na interface osso-implante de 79,69 por cento ± 1,00 e 65,05 ± 1,23 para os implantes de superfície porosa e rugosa, respectivamente, e foi observada diferença estatisticamente significante entre os dois tipos de implantes com relação à quantidade de neoformação óssea. Concluiu-se que os implantes de superfície porosa contribuíram para a osseointegração devido à sua maior superfície de contato na interface osso-implante.