Demineralized Human Dentin Matrix as an Osteoinductor in the Dental Socket: An Experimental Study in Wistar Rats.

PURPOSE: This study evaluated the bone-forming potential of the demineralized human dentin matrix by performing histologic and morphometric analyses. The immunolabeling of osteopontin, a determinant protein for bone repair, was also evaluated. MATERIALS AND METHODS: Wistar rats were selected and submitted to the extraction of the right and left second molars. Tooth sockets were separated into two groups: the control group (right), which was filled with the blood clot, and the experimental group (left), which was filled with demineralized human dentin matrix. Animals were sacrificed at 5, 10, and 21 days. Histologic and histoquantitative analyses (analyses of variance [ANOVA] and Tukey's test) were performed, as well as immunostaining for osteopontin as an osteogenesis indicator. RESULTS: After 5 days, demineralized human dentin matrix was incorporated by new trabeculae. After 10 days, connective tissue organization and new trabeculae were observed in the experimental group, and intense staining for osteopontin close to demineralized human dentin matrix was observed in the experimental group. After 21 days, the experimental group was showing mature trabeculae. A statistical difference was observed (P < .05). There was a higher number of trabeculae in the experimental groups in all periods of analysis. The presence of osteopontin was observed more intensely at 10 days close to demineralized human dentin matrix. CONCLUSION: This study indicates that demineralized human dentin matrix implanted in tooth sockets induces the acceleration of osteogenesis.

Effect of PDGF-BB, IGF-I growth factors and their combination carried by liposomes in tooth socket healing.

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.

Effect of PDGF-BB, IGF-I Growth Factors and their Combination Carried by Liposomes in Tooth Socket Healing

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.

Subclinical failures of direct pulp capping of human teeth by using a dentin bonding system.

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.

TGF-ß1 and BMP-4 carried by liposomes enhance the healing process in alveolar bone.

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.

Enhanced bone healing of rat tooth sockets after administration of epidermal growth factor (EGF) carried by liposome.

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.

Prevalência de maloclusões em escolares de baixo nível socioeconômico / Prevalence of malocclusion in schoolchildren with low socioeconomic status

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.

Histological processing of teeth and periodontal tissues for light microscopy analysis.

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.

Morphology of the dentin on primary molars after the application of phosphoric acid under different conditions.

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.

Morphology of the dentin on primary molars after the application of phosphoric acid under different conditions

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.

Pulp reactions in human teeth capped with self-etching or total-etching adhesive systems.

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.

Microscopia eletrônica de varredura da adaptação marginal de materiais retroobturadores: avaliação histoquantitativa / Scanning electron microscopy of the marginal adaptation of retro-filling materials: histoquantitative evaluation

O objetivo deste trabalho foi verificar a adaptação marginal de materias retroobturadores por microscopia eletrônica de varredura (MEV). Utilizou-se 12 pré-molares inferiores epicetomizados, eliminando-se 3.0 milímetros finais de cada raiz e executando-se em seguida os retropreparos com profundidade de 3,0 milímetros mediante o uso de pontas ultra-sônicas. Dividiram-se os espécimes em três grupos de quatro elementos e foram feitas retroobturações com amálgama, Super EBA e MTA, analisadas em aumento de 1000 X para verificação e medição dos gaps eventualmente encontrados entre o material retroobturador e as paredes dentinárias. Os três materiais testados apresentaram falhas na adaptação marginal.

A genética da odontogênese / Genetic model of tooth development

Este artigo apresenta uma revisão bibliográfica sobre a genética da formação dos dentes. São aqui abordadas as principais moléculas envolvidas na interação epitélio-mesênquima, responsável pela formação da estrutura dental. O objetivo é contribuir para um melhor entendimento da cascata genética envolvida na formação do dente, bem como auxiliar na prática odontológica, procurando despertar a atenção do profissional para o conhecimento científico e facilitar assim a identificação de possíveis problemas, como as más oclusões, suas causas e conseqüências.

Through a review of the literature, this article discusses the genetic mechanisms that control tooth morphogenesis. Emphasis is placed upon the structure and function of some key molecules that participate in interactions between its epithelial-mesenchimal components. In this paper we will understand the mechanisms that control tooth morphogenesis and the dentistry should pay special attention to possible consequences of tooth number anomalies.

Epidermal growth factor in liposomes may enhance osteoclast recruitment during tooth movement in rats.

OBJECTIVE: To evaluate the effects of local administration of epidermal growth factor (EGF) located within liposomes on recruitment of osteoclasts during mechanical force in rats. MATERIALS AND METHODS: An orthodontic elastic band was inserted between the left upper first and second molars, to move mesially the first molar. Rats were randomly divided into 4 groups (n = 8): EGF (2 ng/microL) located within liposomes (group 1), liposomes only (group 2), soluble EGF (2 ng/microL; group 3), or vehicle alone (group 4). The solutions were injected into the region of the root furcation of the left first molar after elastic band insertion. Tooth movement was measured using a plaster model of the maxilla, and the number of osteoclasts recruited at the pressure side of the first molar was histologically evaluated. RESULTS: Intergroup analysis showed that there was no significant difference between group 2 and group 4 (P > .05) and between group 1 and group 3 (P > .05). However, group 1 and group 3 exhibited greater differences in tooth movement than group 2 and group 4 (P < .05). On the other hand, group 1 showed greater tooth movement than groups 2 and 4 with statistical significance (P < .01). The increase in the number of osteoclasts in group 1 was significantly higher than in the other groups (P < .05). CONCLUSION: Exogenous EGF-liposome administration has an additive effect when compared with soluble EGF on the rate of osteoclast recruitment, producing faster bone resorption and tooth movement.

Secretory A immunoglobulin, total proteins and salivary flow in Recurrent Aphthous Ulceration.

UNLABELLED: Clinical and experimental study. Introduction. Of debatable etiology, Recurrent Aphthous Ulcerations (R.A.U), is most of the time considered an immunological deficiency. AIM: The aim of this paper is to review the literature and clinical investigations regarding IgA-s, total proteins salivary concentration and basal salivary flow of patients with R.A.U. during activity and quiescence. METHODOLOGY: Nephelometry was used to measure salivary IgA-s; Pyrogallol red was used for total salivary proteins and the gravimetrical analysis for salivary flow measurement. RESULTS: Results demonstrated a significant increase in salivary IgA-s in active lesions in relation to quiescence. On the other hand, protein concentration rates were similar in both periods. CONCLUSION: Salivary IgA-s can be used as a parameter to study the immune status of the oral mucosa.

Imunoglobulina A secretora, proteínas totais e fluxo de saliva nas ulcerações aftosas recorrentes / Secretory A immunoglobulin, total proteins and salivary flow in Recurrent Aphthous Ulceration

De etiologia discutível, as ulcerações aftosas recorrentes (UAR) são, na maioria das vezes, consideradas em um quadro de deficiência imunológica. OBJETIVOS: Este trabalho baseia-se na revisão de literatura e em investigações clínico-laboratoriais dos títulos salivares de imunoglobulina A secretora (IgA-s), proteínas totais e fluxo de saliva (em repouso) de pacientes nos períodos de atividade e quiescência das Ulcerações aftosas recorrentes. Forma de Estudo: Estudo clínico e experimental. MATERIAL E MÉTODOS: Empregou-se a Nefelometria na quantificação das IgA-s salivares, o vermelho de Pirogalol para as proteínas totais salivares e a análise gravimétrica para a determinação do fluxo de saliva. RESULTADOS: Os resultados demonstraram aumento estatisticamente significativo das IgA-s salivares nos períodos de lesão ativa em relação aos de quiescência. Não houve diferença estatística nas concentrações de proteínas totais e no fluxo de saliva. CONCLUSÃO: Sugere-se que a IgA-s pode ser usada como parâmetro do status imune da mucosa oral.

Clinical and experimental study. Introduction. Of debatable etiology, Recurrent Aphthous Ulcerations (R.A.U), is most of the time considered an immunological deficiency. AIM: The aim of this paper is to review the literature and clinical investigations regarding IgA-s, total proteins salivary concentration and basal salivary flow of patients with R.A.U. during activity and quiescence. METHODOLOGY: Nephelometry was used to measure salivary IgA-s; Pyrogallol red was used for total salivary proteins and the gravimetrical analysis for salivary flow measurement. RESULTS: Results demonstrated a significant increase in salivary IgA-s in active lesions in relation to quiescence. On the other hand, protein concentration rates were similar in both periods. CONCLUSION: Salivary IgA-s can be used as a parameter to study the immune status of the oral mucosa.

Efeito da matriz dentinária humana no reparo alveolar de ratos: avaliação histológica e imunohistoquímica / Effect of human dentin matrix on alveolar repair of rats: histological and immunohistochemical study

Objetivos: A dentina pode ser considerada um tecido mineralizado que exibe muitas similaridades com o osso, dentre elas a presença de fatores de crescimento e proteínas morfogenéticas do osso. A capacidade de osteoindução da matriz dentinária parece ser devido à presença das proteínas morfogenéticas do osso. O presente estudo avaliou o efeito da matriz dentinária no reparo alveolar de ratos. Métodos: Dezessete ratos da raça Holtzman, adultos, do sexo feminino fizeram parte da pesquisa. Os primeiros molares maxilares direito e esquerdo foram extraídos e os alvéolos do lado esquerdo preenchidos com matriz dentinária humana desmineralizada, os alvéolos direitos foram os controles. A amostra foi dividida em quatro grupos. O grupo I era composto por dois animais, sacrificados imediatamente após a exodontia, enquanto os demais grupos II, III e IV por cinco animais cada sacrificados no tempo cinco, dez e vinte e um dias, respectivamente. Após a fixação e desmineralização, os espécimes foram incluídos em parafina, cortados em micrótomo com 6mm de espessura, corados em H.E. e analisados a microscopia de luz. Resultados: No grupo de cinco dias, a matriz dentinária reduziu a reação inflamatória e o tecido conjuntivo estava mais organizado, quando comparado ao grupo controle. A dentina implantada possuía células aderidas à superfície bem como no interior dos canalículos dentinários. Entretanto, em alguns animais desse grupo, ocorreu uma resposta inflamatória intensa que levou à expulsão da matriz dentinária, caracterizando o processo de rejeição do material de implante. Nestes casos realizou-se a técnica imunohistoquímica para células sugestivas de macrófagos e células gigantes. No grupo de dez dias, essa matriz parecia estar promovendo a angiogênese e no grupo de vinte e um dias a dentina estava incorporada na matriz óssea. Conclusão: Esses resultados sugerem que a matriz dentinária possui propriedades compatíveis com a redução da reação inflamatória e de acelerar...

Direct pulp capping with a dentin bonding system in human teeth: a clinical and histological evaluation.

This study evaluated the pulpal response in human dental pulp to direct pulp capping with the Single Bond Adhesive System (SBAS) after 10% or 37% phosphoric acid etching and after capping with Calcium Hydroxide (CH). The degree of bleeding and hemostasis conditions was considered during the adhesive technique. The pulps of 78 sound premolars were capped with SBAS after 37% phosphoric acid etching (Group I) or 10% phosphoric acid etching (Group II) and CH (Group III-control). The cavities were restored with a resin composite (Charisma). After 1, 3, 7 and 30 days, the teeth were extracted and processed for light microscopical examination (H/E, AgNOR silver stain and Brown-Brenn). The patients were followed for postoperative symptomatology evaluation. Clinical results showed the possibility of hemostasis with saline solution only. There was no statistical difference between bleeding generated by 10% and 37% acid solutions. In some cases, contact of the pulp tissue with SASB started the bleeding process, thus damaging the adhesive technique. The histological response was similar in Groups I and II, without signs of cellular differentiation and dentin neoformation up to 30 days. Bacteria were not observed in any specimens. In the control group (CH) at day 7, the pulps exhibited cells with high synthetic activity (Ag-NOR-positive) underneath the area of coagulation necrosis. Dentin bridging was observed at the thirtieth day. The postoperative period was asymptomatic for all groups. In conclusion, SBAS should be avoided for vital pulp therapy, while CH remains the capping agent of choice for mechanically exposed human dental pulp.

A morphological in vitro study of the effects of Nd:YAG laser on irradiated cervical dentin.

OBJECTIVE: The purpose of this in vitro study was to verify the efficacy of Nd:YAG pulsed laser at 1064 nm in sealing dentinal tubules in vitro, with its resulting morphological changes using clinical parameters applicable to the treatment of dentin hypersensitivity. BACKGROUND DATA: Although many papers have been written on the subject, no rapid, efficient, and long-lasting treatment for this problem has been developed. MATERIALS AND METHODS: Twenty healthy extracted human teeth were kept in saline solution. Cervical cement was removed with a no. 57FG bur to expose approximately 4 mm(2) of dentin. Two groups were in the buccal aspect (A and B-irradiated) and one group in the lingual aspect (C-control not irradiated) of the same tooth. Samples with a remaining dentinal thickness between 1 and 1.5 mm were selected. Irradiation parameters were 30 mJ, 0.3W(Group A) and 40 mJ, 0.4 W(Group B); 7 Hz was used in both groups in two 43-sec applications each, with a 10-sec interval. In 10 samples, the dentinal surface underwent SEM examination for study. The other 10 remaining irradiated samples were centrally cleaved to study laser penetration depth in dentin (SEM). RESULTS: Obliteration of dentinal tubule openings and solidification of the dentin surface were observed in all irradiated samples. Laser penetration depth in dentin (SEM) varied from 1 to 7 microm, depending on irradiation parameters used in each group. CONCLUSION: We concluded that the use of the Nd:YAG laser was a very effective measure for obliterating dentinal tubule openings.

Modulation of granulomatous hypersensitivity against Schistosoma mansoni eggs in mice vaccinated with culture-derived macrophages loaded with PIII.

Granuloma modulation induced by antigen is an attractive model for vaccination studies of experimental schistosomiasis to test the effect of anti-pathology vaccine. We describe here an immunization procedure with culture derived macrophages-pulsed PIII, a known anionic antigen purified from S. mansoni adult worm, involved in the inhibition of granulomatous response to eggs. For our studies, peritoneal or spleen macrophages cultured over 15 days were loaded with PIII. Both macrophage sub-populations were capable to efficiently take up and subsequently present PIII to lymphocytes as evidenced by immunofluorescence assay. The vaccination of mice with intravenous injection of PIII-loaded macrophages potently induced antigen-specific immune response to S. mansoni antigens as determined by cell proliferation assay. This immunization procedure of mice caused significant decrease in hepatic granuloma formation and in vitro granuloma reaction to S. mansoni antigens coupled to polyacrylamide beads (PB-SEA, PB-SWAP or PB-PIII). Assessment of in vitro granuloma supernatant of spleen cells from PIII-loaded macrophages vaccinated mice revealed significant amounts of Th1-cytokines IFN-gamma and IL-2 compared to control cells. Collectively, our results indicate that culture derived-macrophages provided a valuable research tool to investigate aspects of immune response that promote modulation of granulomatous hypersensitivity to S. mansoni eggs in mice.