RESUMO
This work evaluated the bone-forming potential of the platelet-derived growth factor isoform BB (PDGF-BB), insulin-like growth factor I (IGF-I), and mixed PDGF-BB/IGF-I delivered in liposomes compared with phosphate buffered saline (PBS), in the healing process of rat tooth sockets. One hundred and twelve Wistar rats were randomized into 7 groups of 16 animals each and were evaluated at 3, 7, 14 and 21 days after extraction of the maxillary second molars. The left sockets were treated with PBS (P), empty liposome (L), IGF-I in PBS (IP), IGF-I in liposome (IL), PDGF-BB in PBS (PDP), PDGF-BB in liposome (PDL) and both growth factors (GFs) together within liposomes (PDIL). The right sockets were filled with blood clot (BC). Histological and histomorphometric analyses were used to evaluate the formation of new bone and blood vessels. Immunohistochemistry was performed to evaluate the expression of osteocalcin and vascular endothelial growth factor (VEGF) during bone repair. Data were tested statistically using a Tukey's test according to a Dunn's analysis and Mann-Whitney U test followed by Kruskal-Wallis one-way analysis. Results were considered significant when p<0.05. A significantly higher percentage of bone trabeculae and a higher number of blood vessels were observed in the IL, PDL and PDIL groups (p<0.05). However, these GF-liposome groups had statistically similar results. Immunohistochemical assays first detected osteocalcin and VEGF expression at 3 days followed by a peak at 7 days. Lower immunoreactivity levels were observed in the BC, L, P, IP and PDP groups compared with the IL, PDL and PDIL groups (p<0.05). The results suggest that GFs carried by liposomes, either in isolated or mixed forms, enhanced the healing process in rat tooth sockets. The differential expression of the osteogenic markers VEGF and osteocalcin in the early phases of bone healing support these findings.
Assuntos
Fator de Crescimento Insulin-Like I/administração & dosagem , Lipossomos , Proteínas Proto-Oncogênicas c-sis/administração & dosagem , Alvéolo Dental/patologia , Cicatrização/efeitos dos fármacos , Animais , Becaplermina , Fator de Crescimento Insulin-Like I/farmacologia , Masculino , Proteínas Proto-Oncogênicas c-sis/farmacologia , Ratos , Ratos WistarRESUMO
This work evaluated the bone-forming potential of the platelet-derived growth factor isoform BB (PDGF-BB), insulin-like growth factor I (IGF-I), and mixed PDGF-BB/IGF-I delivered in liposomes compared with phosphate buffered saline (PBS), in the healing process of rat tooth sockets. One hundred and twelve Wistar rats were randomized into 7 groups of 16 animals each and were evaluated at 3, 7, 14 and 21 days after extraction of the maxillary second molars. The left sockets were treated with PBS (P), empty liposome (L), IGF-I in PBS (IP), IGF-I in liposome (IL), PDGF-BB in PBS (PDP), PDGF-BB in liposome (PDL) and both growth factors (GFs) together within liposomes (PDIL). The right sockets were filled with blood clot (BC). Histological and histomorphometric analyses were used to evaluate the formation of new bone and blood vessels. Immunohistochemistry was performed to evaluate the expression of osteocalcin and vascular endothelial growth factor (VEGF) during bone repair. Data were tested statistically using a Tukey's test according to a Dunn's analysis and Mann-Whitney U test followed by Kruskal-Wallis one-way analysis. Results were considered significant when p<0.05. A significantly higher percentage of bone trabeculae and a higher number of blood vessels were observed in the IL, PDL and PDIL groups (p<0.05). However, these GF-liposome groups had statistically similar results. Immunohistochemical assays first detected osteocalcin and VEGF expression at 3 days followed by a peak at 7 days. Lower immunoreactivity levels were observed in the BC, L, P, IP and PDP groups compared with the IL, PDL and PDIL groups (p<0.05). The results suggest that GFs carried by liposomes, either in isolated or mixed forms, enhanced the healing process in rat tooth sockets. The differential expression of the osteogenic markers VEGF and osteocalcin in the early phases of bone healing support these findings.
Este trabalho avaliou o potencial de formação óssea do fator de crescimento derivado de plaquetas na isoforma BB (PDGF-BB), fator de crescimento semelhante à insulina I (IGF-I), e a mistura PDGF-BB/IGF-I administrada em lipossomas comparando com tampão fosfato salino (PBS), no processo de cicatrização de alvéolos dentários de ratos. Cento e doze ratos Wistar foram distribuídos aleatoriamente em 7 grupos de 16 animais cada e foram avaliados aos 3, 7, 14 e 21 dias após a extração dos segundos molares maxilares. Os alvéolos esquerdos foram tratados com PBS (P), lipossomas vazios (L), IGF-I em PBS (IP), IGF-I em lipossomas (IL), PDGF-BB em PBS (PDP), PDGF-BB em lipossomas (PDL) e ambos os fatores de crescimento (GFs) em associação dentro de lipossomas (PDIL). Os alvéolos direitos foram preenchidos com coágulo sanguíneo (BC). As análises histomorfométrica e histológica foram utilizadas para avaliar a formação de novo osso e vasos sanguíneos. Imunohistoquímica foi realizada para avaliar a expressão de osteocalcina e o fator de crescimento endotelial vascular (VEGF) durante o reparo ósseo. Os dados foram testados estatisticamente utilizando o teste de Tukey em acordo com análise de Dunn e o teste Mann-Whitney U seguido pela análise de um passo de Kruskal-Wallis. Os resultados foram considerados significantes quando p<0,05. Uma percentagem altamente significativa de osso trabecular e alto número de vasos sanguíneos foram observados nos grupos IL, PDL e PDIL (p<0,05). Todavia, esses grupos lipossoma-GF tiveram resultados similares estatisticamente. Ensaios de imunohistoquímica inicialmente detectaram a expressão de osteocalcina e VEGF aos 3 dias, seguida por um pico aos 7 dias. Niveis mais baixos de imunorreatividade foram observados em BC, L, P, PI e PDP quando comparados com os grupos IL, PDL e PDIL (p<0,05). Os resultados sugerem que GFs carreados por lipossomas, na forma isolada ou em combinação, aceleram o processo de cicatrização em alvéolos dentários de rato. A expressão diferencial dos marcadores osteogênicos VEGF e osteocalcina, nas fases iniciais de cicatrização óssea, confirma esses achados.
Assuntos
Animais , Masculino , Ratos , Fator de Crescimento Insulin-Like I/administração & dosagem , Lipossomos , Proteínas Proto-Oncogênicas c-sis/administração & dosagem , Alvéolo Dental/patologia , Cicatrização/efeitos dos fármacos , Fator de Crescimento Insulin-Like I/farmacologia , Proteínas Proto-Oncogênicas c-sis/farmacologia , Ratos WistarRESUMO
INTRODUCTION: The goal of this study was to examine the adhesive interface of pulp tissue to investigate subclinical failures after direct pulp capping (DPC) of human teeth by using a dentin adhesive system. METHODS: The pulps of 12 caries-free first premolars scheduled for extraction for orthodontic reasons were exposed and capped with the Single Bond adhesive system. The adhesive technique was carefully performed to ensure complete coverage of the exposed area and a satisfactory clinical aspect. After 1 (n = 6) and 30 days (n = 6), the teeth were extracted for evaluation of the adhesive interface under light microscopy and scanning electron microscopy. Brown-Brenn staining was used to detect bacteria. RESULTS: The clinical aspect of direct pulp capping during the operation was satisfactory, and all patients were asymptomatic in the postoperative phase. Brown-Brenn staining revealed no bacterial microleakage at both time points. A hybrid layer was seen on all walls but decreased gradually toward the area of pulp exposure. In contrast to clinical data, light microscopy and scanning electron microscopy revealed important subclinical bond failures near the area of exposed pulp. Some frequent findings were gaps between the restoration and the dentin substrate; unpolymerized monomers under the adhesive layer; interface breaks with blood extravasation between the layers of the adhesive system; rupture of the odontoblast layer; and multinucleated giant cells close to the bonding agent. CONCLUSIONS: The Single Bond adhesive system should not be used for direct pulp capping of human teeth because subclinical adhesive failures invariably occur at its interface with the pulp tissue.
Assuntos
Capeamento da Polpa Dentária/métodos , Adesivos Dentinários/uso terapêutico , Agentes de Capeamento da Polpa Dentária e Pulpectomia/uso terapêutico , Condicionamento Ácido do Dente/métodos , Dente Pré-Molar/patologia , Bis-Fenol A-Glicidil Metacrilato/uso terapêutico , Corantes , Colagem Dentária , Preparo da Cavidade Dentária/métodos , Infiltração Dentária/classificação , Polpa Dentária/patologia , Exposição da Polpa Dentária/terapia , Eritrócitos/patologia , Seguimentos , Células Gigantes/patologia , Humanos , Microscopia Eletrônica de Varredura , Odontoblastos/patologia , Ácidos Fosfóricos/química , Polimerização , Propriedades de Superfície , Falha de TratamentoRESUMO
OBJECTIVE: In this work we evaluated the bone-forming potential of BMP4, TGFß1 and BMP4/TGFß1 mixed by performing histological and morphometric analysis. We also evaluated the immunolabelling of fibronectin (FN) and collagen type III (Col III), two determinant proteins for the early phase of bone repair. DESIGN: Histological, histomorphometric and immunohistochemistry analysis were used to evaluate new bone and blood vessels formation as well as fibronectin and collagen type III expression. 112 male Wistar rats weighing 250-300g had their maxillary second molar extracted. Sockets filled with blood clot (BC) or treated with L (empty liposome), P (PBS), BP (BMP-4 in PBS) and TP (TGF-ß1 in PBS), as well as with BL (BMP-4 in liposome) and TL (TGF-ß1 in liposome) administered isolated or in association (BTL) were obtained. The animals were sacrificed at 3, 7, 14 and 21 days after surgery. RESULTS: An increased percentage of bone trabeculae, and a higher number of blood vessels were observed in groups BL or TL administered isolated or in association when compared to groups BC, L, P, BP and TP. Fibronectin and collagen type III analysis revealed enhanced expression firstly detected at 3 days followed by a peak at 7 days. Lower levels of immunoreactivity were observed in the sockets filled with blood clot, and treated with L, P, BP and TP when compared with sockets from groups BL, TL and BTL. CONCLUSION: The present study indicates growth factors carried by liposomes, either in isolated or associated forms, as successful enhancers of the healing process in rat tooth sockets. We also conclude that the expression of fibronectin and collagen type III increases during the early phases of bone repair.
Assuntos
Processo Alveolar/efeitos dos fármacos , Proteína Morfogenética Óssea 4/administração & dosagem , Osteogênese/efeitos dos fármacos , Fator de Crescimento Transformador beta1/administração & dosagem , Processo Alveolar/irrigação sanguínea , Processo Alveolar/patologia , Animais , Coagulação Sanguínea/fisiologia , Proteína Morfogenética Óssea 4/farmacologia , Colágeno Tipo III/efeitos dos fármacos , Portadores de Fármacos , Fibronectinas/efeitos dos fármacos , Lipossomos , Masculino , Maxila/irrigação sanguínea , Maxila/efeitos dos fármacos , Maxila/patologia , Maxila/cirurgia , Neovascularização Fisiológica/efeitos dos fármacos , Osteoblastos/efeitos dos fármacos , Osteoblastos/patologia , Osteoclastos/efeitos dos fármacos , Osteoclastos/patologia , Distribuição Aleatória , Ratos , Ratos Wistar , Fatores de Tempo , Extração Dentária , Alvéolo Dental/irrigação sanguínea , Alvéolo Dental/efeitos dos fármacos , Alvéolo Dental/patologia , Alvéolo Dental/cirurgia , Fator de Crescimento Transformador beta1/farmacologia , Cicatrização/efeitos dos fármacosRESUMO
Considering the potential use of growth factors carried by liposomes for bone repair, this study aimed to assess the progress of bone healing process in injured alveoli of rats after administering EGF within liposomes. For this assessment we used 48 male Wistar rats that had their maxillary second molar extracted and separated into 5 groups: sockets filled with blood clot (BC), treated with empty liposome (L), PBS (P), EGF in PBS (EGF-P) and EGF in liposome (EGF-L). The animals were sacrificed after 3, 7, 14 and 21 days after surgery. Histological, histomorphometric and immunohistochemistry analysis were performed to evaluate new bone and blood vessels formation as well as the expression of fibronectin and collagen type III, two determinant proteins for early wound regeneration. Our analysis showed a continuous transformation of sockets during all stages of wound healing. Nevertheless, groups BC, L, P and EGF-P followed a regular time for regeneration significantly different from the EGF-L group, which showed faster recovering. A higher expression of fibronectin and type III collagen in the group EGF-L after 3 and 7 days of surgery was observed and might be explained by the ability of the liposome to deliver EGF in a controlled manner, stimulating mesenchymal cells migration and osteoblast differentiation. As liposome efficiently regulated the availability of EGF without risks for its function and protected the factor from early absorption and degradation, the present work indicates that liposomes can be successful used as carriers for controlled delivery of growth factors in bone healing.
Assuntos
Regeneração Óssea , Fator de Crescimento Epidérmico/metabolismo , Lipossomos/metabolismo , Maxila/metabolismo , Alvéolo Dental/metabolismo , Cicatrização , Animais , Preparações de Ação Retardada , Fator de Crescimento Epidérmico/farmacologia , Lipossomos/farmacologia , Masculino , Ratos , Ratos WistarRESUMO
OBJETIVO: Caracterizar a prevalência de maloclusões em escolares de 5 a 7 anos, com baixo nível socioeconômico e contribuir para o planejamento de ações de intervenção em Uberaba, Minas Gerais. MÉTODOS: Foram selecionadas, aleatoriamente, três escolas públicas para participarem do estudo localizadas nos três distritos sanitários da cidade. As crianças foram examinadas em ambiente escolar por examinadora e auxiliares treinadas. Foi examinado o universo de crianças, cujos responsáveis consentiram a participação no estudo. O instrumento de coleta de dados utilizou itens que constam nas classificações de Fisk e Moyers e outros auxiliares no diagnóstico das maloclusões. Para verificar a relação entre as variáveis foi realizado o teste qui-quadrado. Os dados foram analisados no programa estatístico SPSS 14.0 e o nível de significância adotado foi α<0,05. RESULTADOS: Apresentaram algum tipo de maloclusão 87,7 por cento das crianças, sendo que 55,8 por cento de pele branca ou parda e oclusão tipo I (χ2 = 39,210 p<0,0001). Apresentaram fala normal 88,6 por cento, porém as crianças com 6 anos apresentaram um índice elevado de anormalidade na fala (49,2 por cento), quando comparadas às demais (χ2 = 18,455 p<0,05). A prevalência de mordida cruzada foi igual a 12,6 por cento. CONCLUSÃO: A prevalência das maloclusões apresentou-se alta em escolares de 5 a 7 anos de baixo nível socioeconômico em Uberaba, Minas Gerais. Há necessidade de elaboração de propostas de orientação para as crianças e seus familiares, envolvendo o sistema de saúde pública municipal para a adoção de estratégias preventivas.
OBJECTIVE: To characterize the prevalence of malocclusion in children 5 to 7 years, with low socioeconomic status, and contribute to the planning of interventions in Uberaba, Minas Gerais, Brazil. METHODS: We randomly selected three schools to participate in the study, located in three health districts. Children were examined in the school environment by trained examiners and assistants. We examined the population of children whose parents consented for their children to participate in the study. The instrument used for data items contained in the classifications of Fisk and Moyers and other aid in the diagnosis of malocclusion. The relationship between malocclusion and collected variables was determined using chi-square test. The data were analyzed with SPSS 14.0 and the level of significance was set at α < 0.05. RESULTS: 87.7 percent of children had some type of malocclusion, and 55.8 percent had white skin or brown and occlusion type I (χ2 = 39.210 p<0.0001). 88.6 percent had normal speech, and children under 6 years showed a high rate of abnormality in speech (49.2 percent) compared with other children (χ2 = 18.455 p<0.05). The prevalence of crossbite was 12.6 percent. CONCLUSION: The prevalence of malocclusion was high in children 5 to 7 years with low socioeconomic status in Uberaba, MG. It is important to develop guidelines for children and their families and to involve the public health system to implement preventive strategies.
Assuntos
Humanos , Masculino , Feminino , Pré-Escolar , Criança , Má Oclusão/epidemiologia , Fatores Etários , Fatores Sexuais , Fatores SocioeconômicosRESUMO
It is possible to obtain histological preparation of teeth and periodontium with satisfactory levels of quality by means of routine histological techniques, since specific cares are implemented during the sample processing. The formation of access ducts for the quick penetration of the fixative solution, the complete removal of the demineralizing agent and the increase of the time of dehydration, clearing, and paraffin embedding are some of these cares. A variety of fixing and demineralizing solutions have been proposed in the literature for teeth and periodontium processing. The author's' experience along the years demonstrated the possibility of satisfactory results with 10% buffered neutral formalin as fixative solution and 10% pH 7.3 EDTA as demineralizing solution. Sections of 6 µm in thickness obtained from paraffin-embedded samples, stained with hematoxylin and eosin, comply with the most morphological and morphometric evaluations. Besides, this routine protocol allows the use of serial sectioning for more specific techniques such as histochemical and immunohistochemical analyses, which are suitable for cellular constituent and extracellular matrix evaluation of teeth and periodontium. For the study of mineralized phases of isolated human teeth, ground sections can be obtained by the cutting-grinding technique. Though it is a recognized method of study, there are some technical difficulties involved, which are little exploited in the literature. This chapter presents a detailed cutting-grinding protocol for the histological evaluation of undecalcified isolated teeth and routine histology, which can be easily reproduced in any research or teaching support laboratory.
Assuntos
Técnicas de Preparação Histocitológica/métodos , Microscopia/métodos , Periodonto/citologia , Preservação de Tecido/métodos , Dente/anatomia & histologia , Ácido Edético , Fixadores , Formaldeído , Hematoxilina , HumanosRESUMO
The aim of this study was to evaluate changes in the superficial dentin pattern of primary teeth after applying different phosphoric acid concentrations and conditioning times. Twenty-four dentin surfaces were divided in 4 groups with 10 teeth each: GI -no treatment; GII to GIV -phosphoric acid at 37%, 32%, and 10% respectively. The samples were divided into two halves: one treated for 7 seconds (T1) and the other one for 15 seconds (T2). They were submitted to scanning electronic microscopy (SEM). A reticule was superimposed upon the images to randomly select dentinal tubules measured in µm². The conditioning times did not cause significant differences in the mean diameter values of the dentin tubules within each test group: GII (T1= 4.86; T2= 4.70); GIII (T1 = 3.83; T2= 3.08); GIV (T1= 5.04; T2= 5.23). Comparing different groups, there were no differences in T1. The same results were observed in T2, except for GIV which presented higher mean diameter values than GIII. The extent of acid conditioning did not influence tubule opening within groups. When different types of acids where compared, only the 10% phosphoric acid showed upper tubule opening than 32% phosphoric acid. The dentin pattern varied according to the type of acid used for conditioning.
Assuntos
Condicionamento Ácido do Dente , Dentina/efeitos dos fármacos , Dente Molar/efeitos dos fármacos , Ácidos Fosfóricos/farmacologia , Dente Decíduo/efeitos dos fármacos , Análise de Variância , Dentina/anatomia & histologia , Humanos , Microscopia Eletrônica de Varredura , Dente Molar/anatomia & histologia , Ácidos Fosfóricos/administração & dosagem , Camada de Esfregaço , Propriedades de Superfície/efeitos dos fármacos , Fatores de Tempo , Dente Decíduo/anatomia & histologiaRESUMO
The aim of this study was to evaluate changes in the superficial dentin pattern of primary teeth after applying different phosphoric acid concentrations and conditioning times. Twenty-four dentin surfaces were divided in 4 groups with 10 teeth each: GI -no treatment; GII to GIV -phosphoric acid at 37 percent, 32 percent, and 10 percent respectively. The samples were divided into two halves: one treated for 7 seconds (T1) and the other one for 15 seconds (T2). They were submitted to scanning electronic microscopy (SEM). A reticule was superimposed upon the images to randomly select dentinal tubules measured in µm². The conditioning times did not cause significant differences in the mean diameter values of the dentin tubules within each test group: GII (T1= 4.86; T2= 4.70); GIII (T1 = 3.83; T2= 3.08); GIV (T1= 5.04; T2= 5.23). Comparing different groups, there were no differences in T1. The same results were observed in T2, except for GIV which presented higher mean diameter values than GIII. The extent of acid conditioning did not influence tubule opening within groups. When different types of acids where compared, only the 10 percent phosphoric acid showed upper tubule opening than 32 percent phosphoric acid. The dentin pattern varied according to the type of acid used for conditioning.
Assuntos
Humanos , Condicionamento Ácido do Dente , Dentina/efeitos dos fármacos , Dente Molar/efeitos dos fármacos , Ácidos Fosfóricos/farmacologia , Dente Decíduo/efeitos dos fármacos , Análise de Variância , Dentina/anatomia & histologia , Microscopia Eletrônica de Varredura , Dente Molar/anatomia & histologia , Ácidos Fosfóricos/administração & dosagem , Camada de Esfregaço , Propriedades de Superfície/efeitos dos fármacos , Fatores de Tempo , Dente Decíduo/anatomia & histologiaRESUMO
OBJECTIVE: Restorative procedures of the dentin-pulp complex stimulate damages that, depending on the technique and materials used, may induce pulpal reactions. The purpose of this study was to evaluate immunochemistry, morphologic, and morphometric pulpal alterations of human teeth pulps capped with self-etching or total-etching adhesive systems. METHOD AND MATERIALS: Thirty human third molars were restored with a resin-based composite and adhesive system, either Clearfil (Kuraray; n = 10) or Scotchbond (3M ESPE; n = 10). After 7, 30, or 60 days, the teeth were extracted and longitudinally sectioned. The pulps were removed for histopathologic and immunochemistry evaluation for interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, and inducible nitric oxide synthase (iNOS). RESULTS: The density of fibrous connective tissue was significantly higher after 30 days in both groups (P < .001). Congestion, hemorrhage, calcification, and swelling of the odontoblasts were similar in both groups. The total capillary area was significantly higher after 7 and 30 days in both groups. Positive immunoreactions for iNOS were found in 1 case (20%) of the 30-day Scotchbond group. Immunoreactions for IFN-gamma were positive in a few cells in 1 case (20%) of the 7-day Clearfil group. There were no positive immunoreactions for TNF-alpha in any case. CONCLUSION: No inflammatory reactions, necrotic areas, or severe immunoreactions for proinflammatory cytokines were found, suggesting biocompatibility of self-etching or total-etching adhesive systems when placed directly on dentin.