Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 12 de 12
Filtrar
Mais filtros

País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
BMC Oral Health ; 24(1): 691, 2024 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-38877464

RESUMO

BACKGROUND: This study evaluated the clinical benefits of adding NanoBone® with split-crest technique and simultaneous implant placement covered with platelet-rich fibrin membrane in horizontally deficient maxillary ridges in terms of crestal and horizontal bone changes and patient morbidity. METHODS: Forty patients indicated for maxillary ridge splitting and simultaneous implant placement were assigned randomly to the study groups: control group (Platelet Rich Fibrin membrane) and test group (Platelet Rich Fibrin membrane + Nanobone®). The Cone Beam Computed Tomography Fusion technique was utilized to assess crestal and horizontal bone changes after five months of the surgical procedure. Patient morbidity was recorded for one week post-surgical. RESULTS: Five months post-surgical, buccal crestal bone resorption was 1.26 ± 0.58 mm for the control group and 1.14 ± 0.63 mm for the test group. Lingual crestal bone resorption was 1.40 ± 0.66 mm for the control group and 1.47 ± 0.68 mm for the test group. Horizontal bone width gain was 1.46 ± 0.44 mm for the control group and 1.29 ± 0.73 mm for the test group. There was no significant statistical difference between study groups regarding crestal and horizontal bone changes and patient morbidity. CONCLUSIONS: The tomographic assessment of NanoBone® addition in this study resulted in no statistically significant difference between study groups regarding crestal and horizontal bone changes and patient morbidity. More randomized controlled clinical trials on gap fill comparing different bone grafting materials versus no grafting should be conducted. GOV REGISTRATION NUMBER: NCT02836678, 13th January 2017.


Assuntos
Perda do Osso Alveolar , Tomografia Computadorizada de Feixe Cônico , Maxila , Fibrina Rica em Plaquetas , Humanos , Masculino , Feminino , Maxila/diagnóstico por imagem , Maxila/cirurgia , Pessoa de Meia-Idade , Perda do Osso Alveolar/diagnóstico por imagem , Implantes Dentários , Adulto , Aumento do Rebordo Alveolar/métodos , Implantação Dentária Endóssea/métodos , Idoso , Minerais/uso terapêutico , Seguimentos , Combinação de Medicamentos , Dióxido de Silício , Durapatita
2.
Biomater Sci ; 12(13): 3374-3388, 2024 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-38787753

RESUMO

This study details the design, fabrication, clinical trials' evaluation, and analysis after the clinical application of 3D-printed bone reconstruction implants made of nHAp@PLDLLA [nanohydroxyapatite@poly(L-lactide-co-D,L-lactide)] biomaterial. The 3D-printed formulations have been tested as bone reconstruction Cranioimplants in 3 different medical cases, including frontal lobe, mandibular bone, and cleft palate reconstructions. Replacing one of the implants after 6 months provided a unique opportunity to evaluate the post-surgical implant obtained from a human patient. This allowed us to quantify physicochemical changes and develop a spatial map of osseointegration and material degradation kinetics as a function of specific locations. To the best of our knowledge, hydrolytic degradation and variability in the physicochemical and mechanical properties of the biomimetic, 3D-printed implants have not been quantified in the literature after permanent placement in the human body. Such analysis has revealed the constantly changing properties of the implant, which should be considered to optimize the design of patient-specific bone substitutes. Moreover, it has been proven that the obtained composition can produce biomimetic, bioresorbable and bone-forming alloplastic substitutes tailored to each patient, allowing for shorter surgery times and faster patient recovery than currently available methods.


Assuntos
Durapatita , Impressão Tridimensional , Humanos , Durapatita/química , Implantes Absorvíveis , Substitutos Ósseos/química , Crânio/cirurgia , Poliésteres/química , Masculino , Desenho de Prótese , Materiais Biocompatíveis/química , Feminino
3.
Biomater Adv ; 160: 213866, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38642518

RESUMO

Research on biomaterials typically starts with cytocompatibility evaluation, using the ISO 10993-5 standard as a reference that relies on extract tests to determine whether the material is safe (cell metabolic activity should exceed 70 %). However, the generalized approach within the standard may not accurately reflect the material's behavior in direct contact with cells, raising concerns about its effectiveness. Calcium phosphates (CaPs) are a group of materials that, despite being highly biocompatible and promoting bone formation, still exhibit inconsistencies in basic cytotoxicity evaluations. Hence, in order to test the cytocompatibility dependence on different experimental setups and material-cell interactions, we used amorphous calcium phosphate, α-tricalcium phosphate, hydroxyapatite, and octacalcium phosphate (0.1 mg/mL to 5 mg/mL) with core cell lines of bone microenvironment: mesenchymal stem cells, osteoblast-like and endothelial cells. All materials have been characterized for their physicochemical properties before and after cellular contact and once in vitro assays were finalized, groups identified as 'cytotoxic' were further analyzed using a modified Annexin V apoptosis assay to accurately determine cell death. The obtained results showed that indirect contact following ISO standards had no sensitivity of tested cells to the materials, but direct contact tests at physiological concentrations revealed decreased metabolic activity and viability. In summary, our findings offer valuable guidelines for handling biomaterials, especially in powder form, to better evaluate their biological properties and avoid false negatives commonly associated with the traditional standard approach.


Assuntos
Materiais Biocompatíveis , Fosfatos de Cálcio , Durapatita , Teste de Materiais , Células-Tronco Mesenquimais , Osteoblastos , Fosfatos de Cálcio/química , Materiais Biocompatíveis/toxicidade , Materiais Biocompatíveis/farmacologia , Humanos , Teste de Materiais/métodos , Teste de Materiais/normas , Células-Tronco Mesenquimais/efeitos dos fármacos , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Apoptose/efeitos dos fármacos , Linhagem Celular , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Animais
4.
J Dent ; 145: 105015, 2024 06.
Artigo em Inglês | MEDLINE | ID: mdl-38657726

RESUMO

OBJECTIVES: To assess and compare the cell viability and ion release profiles of two conventional glass ionomer cements (GICs), Fuji IX and Ketac Molar EasyMix, modified with TiO2 and Mg-doped-HAp nanoparticles (NPs). METHODS: TiO2 NPs, synthesized via a sol-gel method, and Mg-doped hydroxyapatite, synthesized via a hydrothermal process, were incorporated into GICs at a concentration of 5 wt.%. The biocompatibility of prepared materials was assessed by evaluating their effects on the viability of dental pulp stem cells (DPSCs), together with monitoring ion release profiles. Statistical analysis was performed using One-way analysis of variance, with significance level p < 0.05. RESULTS: The addition of NPs did not significantly affect the biocompatibility of GICs, as evidenced by comparable decreased levels in cell viability to their original formulations. Distinct variations in cell viability were observed among Fuji IX and Ketac Molar, including their respective modifications. FUJI IX and its modification with TiO2 exhibited moderate decrease in cell viability, while other groups exhibited severe negative effects. While slight differences in ion release profiles were observed among the groups, significant variations compared to original cements were not achieved. Fluoride release exhibited an initial "burst release" within the initial 24 h in all samples, stabilizing over subsequent days. CONCLUSIONS: The addition of NPs did not compromise biocompatibility, nor anticariogenic potential of tested GICs. However, observed differences among FUJI IX and Ketac Molar, including their respective modifications, as well as induced low viability of DPSC by all tested groups, suggest the need for careful consideration of cement composition in their biological assessments. CLINICAL SIGNIFICANCE: The findings contribute to understanding the complex interaction between NPs and GIC matrices. However, the results should be interpreted recognizing the inherent limitations associated with in vitro studies. Further research avenues could explore long-term effects, in vivo performance, and potential clinical applications.


Assuntos
Sobrevivência Celular , Polpa Dentária , Durapatita , Fluoretos , Cimentos de Ionômeros de Vidro , Magnésio , Teste de Materiais , Nanopartículas , Titânio , Titânio/química , Cimentos de Ionômeros de Vidro/química , Sobrevivência Celular/efeitos dos fármacos , Durapatita/química , Humanos , Polpa Dentária/citologia , Polpa Dentária/efeitos dos fármacos , Nanopartículas/química , Fluoretos/química , Magnésio/química , Células-Tronco/efeitos dos fármacos , Materiais Biocompatíveis/química , Íons , Células Cultivadas
5.
Molecules ; 29(3)2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38338415

RESUMO

Tissue engineering is an interdisciplinary field of science that has been developing very intensively over the last dozen or so years. New ways of treating damaged tissues and organs are constantly being sought. A variety of porous structures are currently being investigated to support cell adhesion, differentiation, and proliferation. The selection of an appropriate biomaterial on which a patient's new tissue will develop is one of the key issues when designing a modern tissue scaffold and the associated treatment process. Among the numerous groups of biomaterials used to produce three-dimensional structures, hydroxyapatite (HA) deserves special attention. The aim of this paper was to discuss changes in the double electrical layer in hydroxyapatite with an incorporated boron and strontium/electrolyte solution interface. The adsorbents were prepared via dry and wet precipitation and low-temperature nitrogen adsorption and desorption methods. The specific surface area was characterized, and the surface charge density and zeta potential were discussed.


Assuntos
Boro , Hidroxiapatitas , Humanos , Hidroxiapatitas/química , Alicerces Teciduais/química , Durapatita , Materiais Biocompatíveis/química , Estrôncio/química , Propriedades de Superfície
6.
Int J Mol Sci ; 25(1)2024 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-38203791

RESUMO

This study reports the effect of the not-calcining process on the bioresorption and biomineralization of hydroxyapatite through in vitro dissolution assessment. The prepared calcined hydroxyapatite (c-HAp) and uncalcined hydroxyapatite (unc-HAp) have a particle size of 2 µm and 13 µm, surface areas of 4.47 m2/g and 108.08 m2/g, and a Ca/P ratio of 1.66 and 1.52, respectively. In vitro dissolution assessments of c-HAp and unc-HAp were performed for 20 days at 37 °C in a citric acid buffer according to ISO 10993-14. During the dissolution, the c-HAp and unc-HAp confirmed an increase in weight, and the calcium and phosphorous ions were rapidly released. The calcium ions released from c-HAp formed rod-shaped particles with a longer and thinner morphology, while in unc-HAp, they appeared thicker and shorter. In the ICP-OES results, the concentrations of calcium elements were initially increased and then decreased by this formation. The rod-shaped particles identified as calcium citrate (Ca-citrate) through the XRD pattern. The calcium content of Ca-citrate particles from unc-HAp was higher than that from c-HAp. The unc-HAp demonstrated non-toxic properties in a cytotoxicity evaluation. Therefore, due to its higher bioresorption and biomineralization, unc-HAp exhibits enhanced biocompatibility compared to c-HAp.


Assuntos
Biomineralização , Cálcio , Citrato de Cálcio , Cálcio da Dieta , Durapatita , Íons
7.
Int J Mol Sci ; 25(2)2024 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-38255941

RESUMO

Many studies have been exploring the use of bone graft materials (BGMs) and mesenchymal stem cells in bone defect reconstruction. However, the regeneration potential of Algipore (highly purified hydroxyapatite) and Biphasic (hydroxyapatite/beta-tricalcium phosphate) BGMs combined with bone marrow-derived mesenchymal stem cells (BMSCs) remains unclear. Therefore, we evaluated their osseointegration capacities in reconstructing peri-implant bone defects. The cellular characteristics of BMSCs and the material properties of Algipore and Biphasic were assessed in vitro. Four experimental groups-Algipore, Biphasic, Algipore+BMSCs, and Biphasic+BMSCs-were designed in a rabbit tibia peri-implant defect model. Implant stability parameters were measured. After 4 and 8 weeks of healing, all samples were evaluated using micro-CT, histological, and histomorphometric analysis. In the energy-dispersive X-ray spectroscopy experiment, the Ca/P ratio was higher for Algipore (1.67) than for Biphasic (1.44). The ISQ values continuously increased, and the PTV values gradually decreased for all groups during the healing period. Both Algipore and Biphasic BGM promoted new bone regeneration. Higher implant stability and bone volume density were observed when Algipore and Biphasic BGMs were combined with BMSCs. Biphasic BGM exhibited a faster degradation rate than Algipore BGM. Notably, after eight weeks of healing, Algipore with BSMCs showed more bone-implant contact than Biphasic alone (p < 0.05). Both Algipore and Biphasic are efficient in reconstructing peri-implant bone defects. In addition, Algipore BGM incorporation with BSMCs displayed the best performance in enhancing implant stability and osseointegration potential.


Assuntos
Células-Tronco Mesenquimais , Procedimentos de Cirurgia Plástica , Animais , Coelhos , Osseointegração , Regeneração Óssea , Durapatita
8.
Actual. osteol ; 15(3): 225-236, Sept-Dic. 2019. ilus
Artigo em Inglês | LILACS | ID: biblio-1116171

RESUMO

Bone grafting is important to preserve the alveolar bone ridge height and volume for dental implant placement. Even though implant-supported overdentures present highly successful outcomes, it seems that a great number of edentulous individuals have not pursued implant-based rehabilitation. The cost of the treatment is one of the reasons of discrepancy between highly successful therapy and its acceptance. Therefore, the development of biomaterials for bone grafting with comparable characteristics and biological effects than those renowned internationally, is necessary. In addition, domestic manufacture would reduce the high costs in public health arising from the application of these biomaterials in the dental feld. The purpose of this clinical case report is to provide preliminary clinical evidence of the efficacy of a new bovine bone graft in the bone healing process when used for sinus floor elevation. (AU)


El uso de injertos óseos es importante para preservar la altura y el volumen de la cresta alveolar para la colocación de implantes dentales. Si bien las sobredentaduras implanto-soportadas presentan resultados altamente exitosos, la mayoría de las personas desdentadas no han sido rehabilitadas mediante implantes dentales. Uno de los principales motivos por los cuales los pacientes no aceptan este tipo de tratamiento, altamente exitoso, es el elevado costo del mismo. Por ello, es necesario el desarrollo de biomateriales de injerto óseo con características y efectos biológicos comparables a los reconocidos internacionalmente. Asimismo, la fabricación nacional reduciría los altos costos en Salud Pública derivados de la aplicación de estos biomateriales en el campo dental. El objetivo de esta comunicación es presentar un caso clínico a fin de proporcionar evidencia preliminar acerca de la eficacia de un nuevo injerto de hueso bovino en el proceso de cicatrización ósea en el levantamiento del piso del seno maxilar. (AU)


Assuntos
Humanos , Animais , Feminino , Pessoa de Meia-Idade , Bovinos , Ratos , Transplante Ósseo/métodos , Arcada Parcialmente Edêntula/reabilitação , Levantamento do Assoalho do Seio Maxilar/métodos , Osteogênese , Argentina , Materiais Biocompatíveis , Bovinos/fisiologia , Carticaína/administração & dosagem , Clorexidina/administração & dosagem , Naproxeno/administração & dosagem , Saúde Pública/economia , Osseointegração , Dentaduras , Transplante Ósseo/tendências , Arcada Parcialmente Edêntula/patologia , Arcada Parcialmente Edêntula/terapia , Durapatita/uso terapêutico , Combinação Amoxicilina e Clavulanato de Potássio/administração & dosagem , Implantação Dentária Endóssea/métodos , Levantamento do Assoalho do Seio Maxilar/tendências , Aloenxertos/imunologia , Aloenxertos/transplante
9.
Comun. ciênc. saúde ; 28(1): [79-84], jan., 2017. graf
Artigo em Português | MS | ID: mis-39796

RESUMO

Os biomateriais nanoestruturados têm se destacado como elementos estratégicos para a medicina regenerativa devido à sua grande área específica, a sua característica de atuar como veículo portador e liberador de fatores de crescimento, células e pela sua mobilidade no plasma, no meio extra e intra-celular. Nos últimos anos, a equipe executora desteestudo, constituída por pesquisadores do CBPF, UFF, UFRJ e INMETRO têm concentrado seus esforços no desenvolvimento de novos fosfatos de cálcio na forma nanoestruturada e com substituições iônicas para uso clínico. Estas características potencializam a bioabsorção do material e suaeficiência na regeneração tecidual, bem como seu uso como nanocarreadorde biomoléculas (proteínas, peptídeos, fatores de crescimento e fármacos).Neste estudo foi produzido e avaliado clinicamente um novo biomaterialpara a regeneração óssea, seguindo o princípio de “quality by desing”,visando aumentar sua eficiência em procedimentos clínicos específicostais como o tratamento do edentulismo. Considerando o enxerto autógenocomo referência, foram realizadas mudanças profundas no desenhodos enxertos de fosfato de cálcio convencionais no sentido de processaro biomaterial na forma de uma matriz microporos não cerâmica constituídapor compósito nanoestruturado de hidroxiapatita carbonatada e obiopolímero alginato de sódio – associado ao concentrado de fatores decrescimento. Este projeto objetivou avaliar clinicamente o ganho ósseo naelevação da membrana sinusal após implantação de microesferas de hidroxiapatitacarbonatada nanoestruturada associadas ao concentrado de...(AU)


These characteristics enhance the bioabsorption of the material and itsefficiency in tissue regeneration, as well as its use as a nanocarrierof biomolecules (proteins, peptides, growth factors and drugs).In this study, a new biomaterial was produced and evaluated clinicallyfor bone regeneration, following the principle of "quality by desing",aiming to increase its efficiency in specific clinical proceduressuch as the treatment of edentulism. Considering the autogenous graftas a reference, profound changes were made in the designof conventional calcium phosphate grafts in the sense of processingthe biomaterial in the form of a non-ceramic microporous matrix constitutedby nanostructured carbonated hydroxyapatite composite and thebiopolymer sodium alginate - associated with the concentration ofgrowth. This project aimed to evaluate clinically the bone gain in theelevation of sinusal membrane after implantation of hydroxyapatite microspherescarbonate concentration associated with thegrowth factors in the liquid phase, obtained from autogenous peripheral blood.Removal of the floor of the maxillary sinus using microspheresof nanostructured carbonated hydroxyapatite associated with or notgrowth factors did not identify the synergistic effect ofbone tissue when biomaterial was associated with growth factorsin the liquid phase. Equivalent bone formation was observed in boththe sides operated after six months of the sinus lift procedure.With this study we conclude that the microafeats of carbonated hydroxyapatitenano-structured is safe and effective for human use and can bea safe alternative for use in the SUS Network in...(AU)


Assuntos
Humanos , Fosfatos de Cálcio , Nanotecnologia , Transplante Ósseo , Bioengenharia , Durapatita , Microesferas , Regeneração Óssea , Seio Maxilar
10.
Brasília; s.n; 2007. 59 p. Dissertação (Mestrado)ilus, tab.
Tese em Português | MS | ID: mis-41205

RESUMO

Objetivos: avaliar a eficácia do tratamento com samário -153 hidroxiapatita(153 Sm-HA) na artropatia hemofílica. Métodos: foram estudados 31 pacientes, 30 do sexo masculino, com idades entre 8 e 34 anos (média = 20,6 anos), com injeção intraarticular fixa de 185 MBq (5 mCi) de 153Sm-HA e divididos em dois grupos...(AU)


Assuntos
Humanos , Hemofilia A , Hemofilia A/tratamento farmacológico , Sinovectomia , Durapatita
11.
Acta cir. bras ; 21(6): 366-373, Nov.-Dec. 2006. ilus
Artigo em Inglês | LILACS | ID: lil-440742

RESUMO

PURPOSE: To evaluate the osteo-regenerative capacity of two proprietary bone grafting materials, using a segmental defect model in both radial diaphyses of rabbits. METHODS: The right defect was filled with pooled bone morphogenetic proteins (pBMPs) bound to absorbable ultrathin powdered hydroxyapatite (HA) mixed with inorganic and demineralized bone matrix and bone-derived collagen, derived from bovine bone (Group A). The left defect was filled with bovine demineralized bone matrix and pBMPs bound to absorbable ultrathin powdered HA (Group B). In both groups, an absorbable membrane of demineralized bovine cortical was used to retain the biomaterials in the bone defects, and to guide the tissue regeneration. The rabbits were euthanized 30, 90 and 150 days after surgery. Radiographic, tomographic and histologic evaluations were carried out on all specimens. RESULTS: At 30 days, the demineralized cortical bone cover was totally resorbed in both groups. HA was totally resorbed from Group A defects, whereas HA persisted in Group B defects. A prominent foreign body reaction was evident with both products, more pronounced in sections from Group B. At 90 days, the defects in Group B exhibited more new bone than Group A. However, at 150 days after surgery, neither treatment had stimulated complete repair of the defect. CONCLUSION: The partial bone healing of the segmental defect occurred with low or none performance of the biomaterials tested.


OBJETIVO: Avaliar a capacidade osteo-regenerativa de dois biomateriais utilizando um modelo de defeito segmentar efetuado nas diáfises do rádio de coelhos. MÉTODOS: O defeito direito foi preenchido com pool de proteínas morfogenéticas ósseas (pBMPs) e hidroxiapatita em pó ultrafina absorvível (HA) combinada com matriz óssea inorgânica desmineralizada e colágeno, derivados do osso bovino (Grupo A). O defeito esquerdo foi preenchido com matriz óssea desmineralizada bovina com pBMPs e hidroxiapatita em pó ultrafina absorvível (Grupo B). Em ambos os defeitos utilizou-se membrana reabsorvível de cortical bovina desmineralizada para reter os biomateriais no defeito ósseo e guiar a regeneração tecidual. Os coelhos foram submetidos à eutanásia aos 30, 90 e 150 dias após a cirurgia. Foram efetuados exames radiográficos, tomográficos e histológicos em todos os espécimes. RESULTADOS: Aos 30 dias de pós-cirúrgico, o osso cortical desmineralizado foi totalmente reabsorvido em ambos os grupos. A HA tinha reabsorvido nos defeitos do Grupo A, mas persistiu nos do Grupo B. Uma reação de corpo estranho foi evidente com ambos os produtos, porém mais pronunciada no Grupo B. Aos 90 dias os defeitos do grupo B tinham mais formação óssea que os do Grupo A. Entretanto, aos 150 dias após a cirurgia, nenhum tratamento havia promovido o completo reparo do defeito. CONCLUSÃO: Os biomateriais testados contribuíram pouco ou quase nada para a reconstituição do defeito segmentar.


Assuntos
Animais , Bovinos , Coelhos , Materiais Biocompatíveis/uso terapêutico , Proteínas Morfogenéticas Ósseas/uso terapêutico , Regeneração Óssea/efeitos dos fármacos , Osso e Ossos/efeitos dos fármacos , Durapatita/farmacocinética , Análise de Variância , Técnica de Desmineralização Óssea , Materiais Biocompatíveis/farmacologia , Matriz Óssea/transplante , Proteínas Morfogenéticas Ósseas/farmacologia , Proteínas Morfogenéticas Ósseas/ultraestrutura , Osso e Ossos/cirurgia , Osso e Ossos/ultraestrutura , Colágeno/administração & dosagem , Modelos Animais de Doenças , Portadores de Fármacos/farmacologia , Portadores de Fármacos/uso terapêutico , Durapatita/uso terapêutico , Regeneração Tecidual Guiada , Período Pós-Operatório , Fatores de Tempo
12.
Rev. ciênc. farm ; 25(2): 111-114, 2004. ilus
Artigo em Português | LILACS | ID: lil-418899

RESUMO

Neste estudo, a formação de biofilme por Candida albicans na superfície de corpos-de-prova de titânio comercialmente puro (Ti-cp) revestidos com hidroxiapatita foi observada por meio de microscópio eletrônico de varredura. O biofilme foi formado após 45 dias de incubação do corpo-de-prova de Ti-cp revestido, em meio de cultura líquido inoculado com as células leveduriformes, contido em tubo de poliestireno com tampa de rosca e esterilização. Após a remoção do biofilme com solução de EDTA 10%, pontos de corrosão foram observados na superfície rugosa/porosa do Ti-cp revestido com hidroxiapatita


Assuntos
Biofilmes/crescimento & desenvolvimento , Candida albicans , Durapatita , Titânio , Materiais Biocompatíveis , Microscopia Eletrônica de Varredura/métodos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA