Macroscopic and microscopic evaluation of flapless alveolar perforations on experimental tooth movement

Abstract Objective: The aim of this study was to evaluate a flapless surgical technique as an alternative to traditional alveolar corticotomy used to accelerate orthodontic tooth movement (OTM). Methods: To induce OTM in Wistar rats, 40 cN of orthodontic force were applied to the maxillary left first molars. Forty rats were distributed into control groups (CG1, CG3, CG7 and CG14) and experimental groups (n= 5), in which alveolar perforations were made using a spear-shaped guide bur (EG1, EG3, EG7, EG14). Euthanasia dates were set at 1, 3, 7 and 14 days, respectively, after tooth movement began. The amount of OTM was measured with a caliper, and osteoclasts present in the periodontal ligament of the mesial root of the moved tooth were counted by means of histological evaluation (tartrate-resistant acid phosphatase staining, TRAP). Results: Although there was no difference in the amount of OTM within subgroups of corresponding experimental periods (p> 0.05), when EG14 and CG14 were compared, a larger number of osteoclasts was counted in the experimental group (p< 0.00). Conclusion: The authors concluded that flapless cortical alveolar perforations led to more intense osteoclastic activity on the fourteenth day; nevertheless, no evidence of accelerated OTM could be noted.

Resumo Objetivo: o objetivo do presente estudo foi avaliar a técnica cirúrgica sem retalho como alternativa à tradicional corticotomia alveolar utilizada para acelerar o movimento dentário experimental. Métodos: para induzir a movimentação dentária experimental em ratos Wistar, foram aplicados 40 cN de força ortodôntica aos primeiros molares superiores esquerdos. Quarenta ratos foram distribuídos nos grupos (n = 5) controles (GC1, GC3, GC7 e GC14) e experimentais (GE1, GE3, GE7, GE14), nos quais foram realizadas perfurações alveolares com uma ponta lança. As datas de eutanásia foram estabelecidas em 1, 3, 7 e 14 dias, respectivamente, após o início do movimento dentário. A quantidade de deslocamento dentário foi medida com um paquímetro e os osteoclastos presentes no ligamento periodontal da raiz mesial do dente movimentado foram contados por meio de avaliação histológica (coloração por fosfatase ácida resistente ao tartarato, TRAP). Resultados: embora não tenha havido diferença na quantidade de deslocamento dentário dentro dos subgrupos dos períodos experimentais correspondentes (p> 0,05), quando GC14 e GE14 foram comparados, um número maior de osteoclastos foi contado no grupo experimental (p< 0,00). Conclusão: os autores concluíram que as perfurações alveolares corticais sem retalho levaram a uma atividade osteoclástica mais intensa no décimo quarto dia; entretanto, nenhuma evidência de movimento dentário acelerado pôde ser notada.

Undifferentiated carcinoma of the pancreas with osteoclast-like giant cells reported in an asymptomatic patient: a rare case and literature review

Undifferentiated carcinoma of the pancreas with osteoclast-like giant cells (UC-OGC) is a rare and poorly described pancreatic malignancy. It is comprised of mononuclear, pleomorphic, and undifferentiated cells as well as osteoclast-like giant cells (OGC's). It constitutes less than 1% of pancreatic non-endocrine neoplasia and is twice as likely to occur in females as in males. Its histopathologic properties remain poorly understood. It is suspected that UC-OGC is of epithelial origin that can then transition to mesenchymal elements. As part of this study, we describe a case of a malignant pancreatic neoplasm that was discovered in a 69-year old patient as an incidental finding. We also provide an overview of previously published data to highlight UC-OGC's clinical and pathologic features.

Osteoporosis and autophagy: What is the relationship? / Osteoporose e autofagia: qual é a relação?

Summary Autophagy is a survival pathway wherein non-functional proteins and organelles are degraded in lysosomes for recycling and energy production. Therefore, autophagy is fundamental for the maintenance of cell viability, acting as a quality control process that prevents the accumulation of unnecessary structures and oxidative stress. Increasing evidence has shown that autophagy dysfunction is related to several pathologies including neurodegenerative diseases and cancer. Moreover, recent studies have shown that autophagy plays an important role for the maintenance of bone homeostasis. For instance, in vitro and animal and human studies indicate that autophagy dysfunction in bone cells is associated with the onset of bone diseases such as osteoporosis. This review had the purpose of discussing the issue to confirm whether a relationship between autophagy dysfunction and osteoporosis exits.

Resumo A autofagia é uma via de sobrevivência celular pela qual proteínas e organelas não funcionais são degradadas nos lisossomos, para reciclagem e geração de energia. Assim, a autofagia é fundamental para a manutenção da homeostase e viabilidade da célula, agindo como um controle de qualidade que evita o acúmulo de estruturas desnecessárias e o estresse oxidativo. Um número crescente de estudos tem demonstrado que disfunções na via autofágica estão relacionadas ao surgimento de diversas doenças, como as neurodegenerativas e o câncer. Estudos também têm indicado que a autofagia exerce um importante papel para a manutenção da homeostase óssea; por exemplo, estudos in vitro e em animais e humanos mostram que disfunções da autofagia nas células ósseas estão associadas ao surgimento de doenças ósseas, como a osteoporose. Nesta revisão, foram abordados esses estudos, a fim de melhor esclarecer se há uma relação entre disfunção autofágica e osteoporose.

The negative prognostic impact of bone metastasis with a tumor mass

OBJECTIVE: Typically, bone metastasis causes osteolytic and osteoblastic lesions resulting from the interactions of tumor cells with osteoclasts and osteoblasts. In addition to these interactions, tumor tissues may grow inside bones and cause mass lesions. In the present study, we aimed to demonstrate the negative impact of a tumor mass in a large cohort of patients with bone metastatic cancer. METHODS: Data from 335 patients with bone metastases were retrospectively reviewed. For the analysis, all patients were divided into three subgroups with respect to the type of bone metastasis: osteolytic, osteoblastic, or mixed. The patients were subsequently categorized as having bone metastasis with or without a tumor mass, and statistically significant differences in median survival and 2-year overall survival were observed between these patients (the median survival and 2-year overall survival were respectively 3 months and 16% in patients with a tumor mass and 11 months and 26% in patients without a tumor mass; p<0.001). RESULTS: According to multivariate analysis, the presence of bone metastasis with a tumor mass was found to be an independent prognostic factor (p=0.011, hazard ratio: 1.62, 95% confidence interval: 1.11–1.76). Bone metastasis with a tumor mass was more strongly associated with osteolytic lesions, other primary diseases (except for primary breast and prostate cancers), and spinal cord compression. CONCLUSION: Bone metastasis with a tumor mass is a strong and independent negative prognostic factor for survival in cancer patients. .

Sarcomatoid cholangiocarcinoma with osteoclast-like giant cells associated with hepatolithiasis: A case report

No abstract available.

The effects of binge-pattern alcohol consumption on orthodontic tooth movement

OBJECTIVE: This study aimed to assess tissue changes during orthodontic movement after binge-pattern ethanol 20% exposure. METHODS: Male Wistar rats (n = 54) were divided into two groups. The control group (CG) received 0.9% saline solution, while the experimental group (EG) received 20% ethanol in 0.9% saline solution (3 g/kg/day). On the 30th day, a force of 25 cN was applied with a nickel-titanium closed coil spring to move the maxillary right first molar mesially. The groups were further divided into three subgroups (2, 14 and 28 days). Tartrate-resistant acid phosphatase and picrosirius were used to assess bone resorption and neoformation, respectively. Data were compared by two-way ANOVA, Tukey's HSD, Games-Howell and chi-square test. Significance level was set at 5%. RESULTS: There was a decrease in the number of osteoclasts in EG at day 28. The percentage of collagen showed no interaction between group and time. CONCLUSION: Binge-pattern 20% ethanol promoted less bone resorption at the end of tooth movement, thereby suggesting delay in tooth movement. .

OBJETIVO: objetivou-se avaliar as alterações teciduais decorrentes da administração de etanol a 20% no padrão binge, durante o movimento ortodôntico. MÉTODOS: foram utilizados ratos Wistar machos (n = 54), divididos em dois grupos, sendo Grupo Controle (GC), com administração de soro fisiológico a 0,9%; e Grupo e Experimental (GE), com administração de etanol a 20% em soro fisiológico a 0,9%, no volume de 3g/kg/dia. Após o 30º dia de administração, foi aplicada força de 25cN com mola fechada de níquel-titânio para mover o primeiro molar superior direito para mesial. Os grupos foram subdivididos nos subgrupos 2, 14 e 28 dias, correspondendo ao número de dias de movimentação dentária. Utilizou-se as colorações de fosfatase ácida-tartarato resistente e picrosírius para avaliar reabsorção óssea e neoformação óssea, respectivamente. Os dados foram comparados por ANOVA a dois critérios, Tukey HSD e Games-Howell, ao nível de significância de 5%. RESULTADOS: verificou-se diminuição no número de osteoclastos no GE II no 28º dia. A percentagem de colágeno não demonstrou alteração na interação grupo x tempo. CONCLUSÕES: o etanol no padrão binge a 20% promoveu menor reabsorção óssea no final da movimentação dentária, sugerindo atraso na movimentação dentária. .

Immunolocalization of FGF-2 and VEGF in rat periodontal ligament during experimental tooth movement

OBJECTIVE: This article aimed at identifying the expression of fibroblast growth factor-2 (FGF-2) and vascular endothelial growth factor (VEGF) in the tension and pressure areas of rat periodontal ligament, in different periods of experimental orthodontic tooth movement. METHODS: An orthodontic force of 0.5 N was applied to the upper right first molar of 18 male Wistar rats for periods of 3 (group I), 7 (group II) and 14 days (group III). The counter-side first molar was used as a control. The animals were euthanized at the aforementioned time periods, and their maxillary bone was removed and fixed. After demineralization, the specimens were histologically processed and embedded in paraffin. FGF-2 and VEGF expressions were studied through immunohistochemistry and morphological analysis. RESULTS: The experimental side showed a higher expression of both FGF-2 and VEGF in all groups, when compared with the control side (P < 0.05). Statistically significant differences were also found between the tension and pressure areas in the experimental side. CONCLUSION: Both FGF-2 and VEGF are expressed in rat periodontal tissue. Additionally, these growth factors are upregulated when orthodontic forces are applied, thereby suggesting that they play an important role in changes that occur in periodontal tissue during orthodontic movement. .

OBJETIVO: o objetivo desse estudo foi identificar a expressão do fator de crescimento de fibroblastos 2 (FGF-2) e do fator de crescimento vascular endotelial (VEGF) nos lados de tensão e pressão do ligamento periodontal de ratos, durante movimento ortodôntico experimental, em diferentes períodos de tempo. MÉTODOS: uma força ortodôntica de 0,5N foi aplicada no primeiro molar superior direito de 18 ratos Wistar machos, por períodos de 3 (grupo I), 7 (grupo II) e 14 dias (grupo III). O primeiro molar do lado oposto foi utilizado como controle. Os animais foram sacrificados nos períodos de tempo mencionados, sendo a arcada superior removida e fixada. Após a desmineralização, os espécimes foram processados histologicamente e embebidos em parafina. A expressão do FGF-2 e do VEGF foram estudadas por meio de análise imuno-histoquímica. RESULTADOS: o ligamento periodontal dos dentes submetidos à movimentação ortodôntica mostraram maior expressão tanto de FGF-2 quanto de VEGF, em todos os grupos experimentais, quando comparados com os dentes do lado controle (p < 0,05). Diferenças estatisticamente significativas entre os lados de tensão e pressão também foram encontradas nos dentes submetidos à movimentação ortodôntica. CONCLUSÕES: tanto o FGF-2 quanto o VEGF são expressos no tecido periodontal de ratos, e esses fatores de crescimento são aumentados quando forças ortodônticas são aplicadas, sugerindo que esses desempenham um papel importante na reorganização do periodonto durante o movimento ortodôntico. .

Sarcomatoid hepatocellular carcinoma with mixed osteoclast-like giant cells and chondroid differentiation

No abstract available.

Remodelação do tecido ósseo peri-implantar e apoptose / Peri-implantar bone tissue remodeling and apoptosis

O processo de remodelação óssea requer aaposição óssea por osteoblastos e a reabsorçãopor osteoclastos. Mecanismos de açãoinfluenciam o equilíbrio celular em contínua remodelaçãoóssea e grande parte das pesquisas direcionou-se para o estudo de fatores capazes de modularas funções. O normal processo de neoformação eadaptação óssea dependem do funcionamento deambos os tipos celulares. O osteoblasto é a célulamais importante nesse processo de reparação durantea osseointegração e o sucesso do tratamentodepende da sua adesão e proliferação. A maiorquota de responsabilidade da plasticidade do tecidoósseo cabe aos osteoclastos que respondema estímulos que promovem reabsorção da matrizinorgânica e liberação de componentes constituintes.Proteínas existentes no interior dososteoclastos atuam como mecanismo de inibiçãosobre as armas de autodestruição ouapoptose. Os processos de morte celular podemser classificados de acordo com suas característicasmorfológicas e bioquímicas em apoptose ou necrose.Na apoptose, não há o derramamento do conteúdocelular como ocorre na necrose e, por estarazão, não existe reação inflamatória.

The process of bone remodeling requires theaffixing by osteoblasts and bone resorptionby osteoclasts. Mechanisms of action influencethe cellular balance continuous remodelingand most of the research directed to thestudy of factors that modulate the functions.Normal process of neoformation and boneadaptation depends on the functioning ofboth cell types. The osteoblast cell is moreimportant in this repair process during osseointegrationand the success of treatmentdepends on the adhesion and proliferation.The largest share of the responsibility of theplasticity of bone tissue is up to osteoclastswhich respond to stimuli that promote reabsorptionof inorganic matrix and release ofcomponents constituents. Proteins withinthe existing osteoclasts act as a mechanismof inhibition on weapons of destruction orapoptosis. The processes of cell death can beclassified according to their morphologicaland biochemical characteristics: apoptosis ornecrosis. In apoptosis, there is no spillage ofthe contents as in cell necrosis and thereforethere is no inflammatory reaction.

Cinética de expressão de moléculas co-estimulatórias de osteoclastos no desenvolvimento da doença periodontal experimental e sua modulação por citocinas / Kinetics of osteoclast co-stimulatory molecules throughout experimental periodontitis and mice and its modulation by cytokines

O processo de diferenciação e ativação de osteoclastos, essencial para a manutenção da homeostasia do tecido ósseo e também envolvido na patogênese de diversas patologias caracterizadas pela atividade osteolítica, depende de um sistema central de controle que envolve a ligação das moléculas RANK/RANKL. Além do sistema RANK/RANKL, moléculas co-estimulatórias de osteoclastos, tais como os complexos DAP-12, TREM-2 e SIRP1, e FcR, OSCAR e PIR-A, também apresentam um papel importante na geração e ativação de osteoclastos. Entretanto, a possível contribuição de tais moléculas para a progressão da doença periodontal (DP) permanece desconhecida, assim como o possível impacto de citocinas na modulação de sua expressão no microambiente periodontal. Nosso objetivo foi investigar, por RealTimePCR, o padrão de expressão de moléculas co-estimulatórias de osteoclastos (DAP-12, TREM-2 e SIRP1, e FcR, OSCAR e PIR-A) na periodontite crônica em humanos, além de avaliar a cinética de expressão destas moléculas e a sua modulação por citocinas (TNF-, IFN-, IL-17 e IL-10) ao longo do curso da DP em camundongos em camundongos C57Bl/6 wild-type (WT) e geneticamente modificados (TNFp55KO, IFNKO, IL17KO, IL10KO. Nossos resultados demonstram que nas lesões periodontais crônicas a expressão de todas as moléculas co-estimulatórias de osteoclastos apresentaram-se significativamente aumentadas quando comparadas às amostras controle. Com relação à periodontite experimental, verificamos que todas as moléculas co-estimulatórias alvo apresentavam aumento em sua expressão após a indução de doença quando comparado aos controles. Nos camundongos para TNFp55KO, IFNKO e IL17KO, observamos uma redução na severidade da DP (reabsorção óssea e quantidade de células inflamatórias) e na expressão de moléculas co-estimulatórias, ao contrário do observado nos camundongos IL10KO. Entretanto, ao normalizarmos os níveis...

The osteoclast differentiation and activation are essential to bone tissue homeostasis and in the development of bone pathologies, which RANK/RANKL signaling molecules are the major osteoclastogenic factor. However, osteoclast co-stimulatory molecules, such as DAP-12, TREM-2, SIRP1, FcR, OSCAR and PIR-A, also present an important role in the osteoclastogenesis. However, the exact role and regulation of these molecules in human and mice periodontal diseases (PD) development have not completely known. Our aim was to investigate the pattern of osteoclast co-stimulatory expression (DAP-12, TREM-2, SIRP1, FcR, OSCAR and PIR-A) in human chronic periodontitis (CP), apart from analyze the kinetic of these molecules and their regulation by cytokines (TNF-, IFN-, IL-17 and IL-10) in the development of experimental periodontal disease in mice C57Bl/6 and knockout. Our results demonstrated that all osteoclast co-stimulatory molecules presented highly expressed in CP patients when compared with control. Similar results are presented about experimental PD, where all co-stimulatory molecules was presented highly expressed in infected mice when compared with control mice. We observed in TNFp55KO, IFNKO and IL17KO mice a decrease in PD scores and co-stimulatory molecules expression, the opposite of IL10KO mice. However, when we standardized the co-stimulatory molecules levels by the number of inflammatory cells, we found that TNF- and IL-17 are associated with increased expression of co-stimulatory molecules, while IFN- and IL-10 appear to negatively regulate the expression of such molecules. In conclusion, we demonstrated that osteoclast co-stimulatory molecules shown increased in human and experimental PD, and cytokines appear to modulate their expression by direct and indirect mechanisms, such as inflammatory cells migration to the PD infected tissue.

Cinética de expressão de moléculas co-estimulatórias de osteoclastos no desenvolvimento da doença periodontal experimental e sua modulação por citocinas / Kinetics of osteoclast co-stimulatory molecules throughout experimental periodontitis and mice and its modulation by cytokines

O processo de diferenciação e ativação de osteoclastos, essencial para a manutenção da homeostasia do tecido ósseo e também envolvido na patogênese de diversas patologias caracterizadas pela atividade osteolítica, depende de um sistema central de controle que envolve a ligação das moléculas RANK/RANKL. Além do sistema RANK/RANKL, moléculas co-estimulatórias de osteoclastos, tais como os complexos DAP-12, TREM-2 e SIRP1, e FcR, OSCAR e PIR-A, também apresentam um papel importante na geração e ativação de osteoclastos. Entretanto, a possível contribuição de tais moléculas para a progressão da doença periodontal (DP) permanece desconhecida, assim como o possível impacto de citocinas na modulação de sua expressão no microambiente periodontal. Nosso objetivo foi investigar, por RealTimePCR, o padrão de expressão de moléculas co-estimulatórias de osteoclastos (DAP-12, TREM-2 e SIRP1, e FcR, OSCAR e PIR-A) na periodontite crônica em humanos, além de avaliar a cinética de expressão destas moléculas e a sua modulação por citocinas (TNF-, IFN-, IL-17 e IL-10) ao longo do curso da DP em camundongos em camundongos C57Bl/6 wild-type (WT) e geneticamente modificados (TNFp55KO, IFNKO, IL17KO, IL10KO. Nossos resultados demonstram que nas lesões periodontais crônicas a expressão de todas as moléculas co-estimulatórias de osteoclastos apresentaram-se significativamente aumentadas quando comparadas às amostras controle. Com relação à periodontite experimental, verificamos que todas as moléculas co-estimulatórias alvo apresentavam aumento em sua expressão após a indução de doença quando comparado aos controles. Nos camundongos para TNFp55KO, IFNKO e IL17KO, observamos uma redução na severidade da DP (reabsorção óssea e quantidade de células inflamatórias) e na expressão de moléculas co-estimulatórias, ao contrário do observado nos camundongos IL10KO. Entretanto, ao normalizarmos os níveis...

The osteoclast differentiation and activation are essential to bone tissue homeostasis and in the development of bone pathologies, which RANK/RANKL signaling molecules are the major osteoclastogenic factor. However, osteoclast co-stimulatory molecules, such as DAP-12, TREM-2, SIRP1, FcR, OSCAR and PIR-A, also present an important role in the osteoclastogenesis. However, the exact role and regulation of these molecules in human and mice periodontal diseases (PD) development have not completely known. Our aim was to investigate the pattern of osteoclast co-stimulatory expression (DAP-12, TREM-2, SIRP1, FcR, OSCAR and PIR-A) in human chronic periodontitis (CP), apart from analyze the kinetic of these molecules and their regulation by cytokines (TNF-, IFN-, IL-17 and IL-10) in the development of experimental periodontal disease in mice C57Bl/6 and knockout. Our results demonstrated that all osteoclast co-stimulatory molecules presented highly expressed in CP patients when compared with control. Similar results are presented about experimental PD, where all co-stimulatory molecules was presented highly expressed in infected mice when compared with control mice. We observed in TNFp55KO, IFNKO and IL17KO mice a decrease in PD scores and co-stimulatory molecules expression, the opposite of IL10KO mice. However, when we standardized the co-stimulatory molecules levels by the number of inflammatory cells, we found that TNF- and IL-17 are associated with increased expression of co-stimulatory molecules, while IFN- and IL-10 appear to negatively regulate the expression of such molecules. In conclusion, we demonstrated that osteoclast co-stimulatory molecules shown increased in human and experimental PD, and cytokines appear to modulate their expression by direct and indirect mechanisms, such as inflammatory cells migration to the PD infected tissue.

Consideraciones en el tratamiento odontológico de pacientes en terapia con bifosfonatos / Considerations in the dental treatment of patients on bisphosphonate therapy

Los bifosfonatos son fármacos de gran utilidad en el diagnóstico y tratamiento de ciertas enfermedades metabólicas óseas. Son utilizados en el tratamiento de mielomas múltiples, metástasis óseas y la hipercalcemia maligna, así como en la prevención y tratamiento de enfermedades del sistema óseo esquelético como la enfermedad de Paget y especialmente la osteoporosis. El objetivo de este artículo es presentar las consideraciones para el tratamiento odontológico de pacientes que van a iniciar o se encuentran en terapia con bifosfonatos a fin de ofrecerles las mejores alternativas terapéuticas que garanticen el correcto manejo de los tejidos bucales y mejorar su calidad de vida

Bisphosphonates are drugs useful in the diagnosis and treatment of certain metabolic bone diseases. This used in the treatment of multiple myeloma, bone metastases and malignant hypercalcemia and in the prevention and treatment of bones diseases skeletal system such as Paget diseases especially osteoporosis. The aim of this paper is to present considerations for dental treatment of patients that will begin or are in bisphosphonate therapy in order to provide the best treatment options to ensure the proper management of the oral tissues and improve their quality of life

Mecanismos celulares e moleculares envolvidos na reabsorção radicular fisiológica de dentes decíduos / Cellular and molecular mechanisms involved in the physiological root resorption of primary teeth

Introdução: A reabsorção fisiológica dos dentes decíduos constitui um fenômeno fisiológico complexo não completamente conhecido; assunto de grande interesse clínico. Os mecanismos celulares e moleculares envolvidos no fenômeno de reabsorção radicular fisiológica parecem ser similares aos mecanismos envolvidos na reabsorção óssea, mediada por osteoclastos. As principais células responsáveis pela reabsorção ativa dos tecidos dentais são os odontoclastos, também denominados de clastos ou osteoclastos; células gigantes multinucleadas originadas de precursores hematopoiéticos de monócitos ou macrófagos. Avanços recentes na literatura específica têm mostrado que a diferenciação e atividade dos osteoclastos, fenômeno também conhecido como osteoclastogênese, são iniciadas e reguladas por diferentes estímulos e sinalizadores moleculares como as citocinas, quimiocinas, produtos de degradação liberados pela superfície radicular afetada, moléculas de adesão, metaloproteinases e pelo sistema RANK/RANKL/OPG. Ainda, o contato físico entre os precursores de osteoclastos e osteoblastos ou células estromais também parece ser necessário para a ativação da osteoclastogênese. Entretanto, o papel específico dos fatores envolvidos no início e modulação da reabsorção radicular dos dentes decíduos permanece desconhecido. Objetivo: Realizar uma revisão de literatura sobre os mecanismos celulares e moleculares envolvidos no processo de reabsorção fisiológica dos dentes decíduos, enfatizando suas implicações clínicas.

Conclusão: Uma complexa interação entre osteclastos, osteoblastos, macrófagos, citocinas, quimiocinas, metaloproteinases, moléculas de adesão e o sistema RANK/RANKL/OPG parecem contribuir para a reabsorção dentária fisiológica. O conhecimento dos mecanismos celulares e moleculares envolvidos no processo de reabsorção fisiológica dos dentes decíduos pode contribuir para o estudo da imunopatogenia das reabsorções dentárias e futuramente resultar na aplicação clínica de mediadores moleculares para atrasar ou mesmo inibir esse processo

Introduction: The physiological resorption of primary teeth is a complex physiological phenomenon that is not completely known and is a subject of great interest. The cellular and molecular mechanisms involved in the phenomenon of physiological root resorption seem to be similar to those involved in bone resorption mediated by osteoclasts. The main cells responsible for the active resorption of the dental tissues are the odontoclasts, which are also known as clasts or osteoclasts; multi nucleated giant cells originated from hematopoietic precursors of monocytes or macrophages. Recent advances published in the literature have shown that the differentiation and activity of osteoclasts, a phenomenon that is also known as osteoclastgenesis, are initiated and regulated by different stimuli and molecular signalizing agents such as cytokines, chemokines, products of degradation released by the affected root surface, adhesion molecules, metalloproteinases, and the RANK/RANKL/OPG system. Moreover, the physical contact between the osteoclasts and osteoblast precursors or stromal cells also seems to be necessary for the activation of osteoclastgenesis. However, the specific role of the factors involved in the initiation and modulation of root resorption of the primary teeth remains unknown. Objective: To perform a review of the literature about the cellular and molecular mechanisms involved in the process of physiological resorption of the primary teeth, emphasizing their clinical implications.

Conclusion: A complex integration among osteoclasts, osteoblasts, macrophages, cytokines, chemokines, metalloproteinases, adhesion molecules and the RANK/RANKL/OPG system seems to contribute to the physiological resorption of teeth. Knowing the cellular and molecular mechanisms involved in the process of physiological root resorption of primary teeth may contribute to the investigation of the immunepathogenesis of dental resorptions, and allow for the clinical application of molecular mediators to delay or even inhibit this process

Effect of carbonated drink on excisional palatal wound healing: A study on Wistar rats.

Background: Millions of people worldwide consume carbonated drinks every day. The effects of these drinks on hard tissues in the mouth have been proved beyond doubt. Only a little has been done so far to assess the effects of carbonated drinks on oral soft tissues. This study was an attempt to assess the effect of carbonated drinks on oral wound healing. Materials and Methods: Twenty female Wistar rats were considered for the study. A circular wound was created on the palate and the animals were divided into two groups (experimental and control group). The experimental group animals were fed with a commercially available carbonated drink instead of water, and two animals from each group were euthanized at 3, 7, 14 and 21 days. Wound site was assessed morphometrically and histologically. Results: There was a marked difference in the healing pattern between the experimental group and control group animals. Control group animals showed a normal healing pattern with formation of a fibrous connective tissue at the end of 21 days. In the experimental group, healing was delayed and disrupted. The wound site showed a definite palatal perforation in experimental group animals after 14 days, but osteoclasts were not noticed in the histological sections. Conclusion: Consumption of carbonated drinks can disrupt oral wound healing. Results suggest that the bone changes seen in experimental group samples are not mediated by osteoclasts, and acidity of the carbonated drinks could be one of the reasons for these changes.

Enhanced bone apposition to Brazilian microrough titanium surfaces

It has recently been reported that machined and microrough (micro) Brazilian titanium (Ti) implants have good production standards. The aim of this study was to evaluate in vivo bone formation around 2 different implant surfaces placed in dog's mandible. Thirty-two screw-typed Ti implants were used in this study. Mandibular premolars were extracted in 8 dogs and, after 12 weeks, 2 machined (Neodent Titamax, Brazil) and 2 micro implants (Neodent Titamax Porous, Brazil) were placed in each animal. Biopsies were taken at 3 and 8 weeks post-implantation and stained with Stevenel's blue and Alizarin red for histomorphometric measurements of bone-to-implant contact (BIC), bone area between threads (BABT) and bone area within the mirror area (BAMA). Data were analyzed statistically by two-way ANOVA (á=0.05). While at 3 weeks micro implants exhibited significantly more BIC than machined ones (55 ± 12.5 percent and 35.6 ± 15 percent, p<0.05), no significant difference in such parameter was detected at 8 weeks (51.2 ± 21 percent and 48.6 ± 18.1 percent, p>0.05). There were no significant differences in BABT and BAMA between the implants. Micro surfaces promoted higher contact osteogenesis. These data indicate that this commercial micro Ti implant surface enhances contact osteogenesis at an early post-implantation period when compared to the machined one.

Estudos recentes demonstram que implantes nacionais de titânio (Ti) usinados e micro-rugosos apresentam padrões adequados de produção. O objetivo deste estudo foi de avaliar a neo-formação óssea in vivo em 2 tipos diferentes de implantes colocados em mandíbulas de cães. Trinta e dois implantes rosqueáveis de Ti foram utilizados neste estudo. Os pré-molares mandibulares de 8 cães foram extraídos e, após 12 semanas, 2 implantes usinados (Neodent Titamax) e 2 implantes micro-rugosos (Neodent Titamax Porous) foram colocados em cada animal. Após 3 e 8 semanas da implantação os espécimes foram biopsiados, corados com Stevenel's blue e Alizarin red e analisados histomorfometricamente quanto à porcentagem de contato-osso-implante (COI), área de osso mineralizado entre as roscas (OMER) e área de osso mineralizado na área em espelho (OMAE). Os resultados foram analisados estatisticamente pelo teste de ANOVA a dois fatores. Os implantes micro-rugosos apresentaram maior COI do que os implantes controle em 3 semanas (55,0 ± 12,5 por cento e 35,6 ± 15,0 por cento; p<0,05), enquanto não houve diferença em 8 semanas (51,2 ± 21,0 por cento e 48,6 ± 18,1 por cento; p>0,05). Não houve diferença quanto ao OMER e OMAE. Esses dados nos indicaram que os implantes micro-rugosos utilizados neste estudo aumentam a osteogênese de contato nos períodos iniciais pós-implantação quando comparados com implantes usinados.

Bone regeneration after demineralized bone matrix and castor oil (Ricinus communis) polyurethane implantation

Innocuous biocompatible materials have been searched to repair or reconstruct bone defects. Their goal is to restore the function of live or dead tissues. This study compared connective tissue and bone reaction when exposed to demineralized bovine bone matrix and a polyurethane resin derived from castor bean (Ricinus communis). Forty-five rats were assigned to 3 groups of 15 animals (control, bovine bone and polyurethane). A cylindrical defect was created on mandible base and filled with bovine bone matrix and the polyurethane. Control group received no treatment. Analyses were performed after 15, 45 and 60 days (5 animals each). Histological analysis revealed connective tissue tolerance to bovine bone with local inflammatory response similar to that of the control group. After 15 days, all groups demonstrated similar outcomes, with mild inflammatory reaction, probably due to the surgical procedure rather than to the material. In the polymer group, after 60 days, scarce multinucleated cells could still be observed. In general, all groups showed good stability and osteogenic connective tissue with blood vessels into the surgical area. The results suggest biocompatibility of both materials, seen by their integration into rat mandible. Moreover, the polyurethane seems to be an alternative in bone reconstruction and it is an inexhaustible source of biomaterial.

Bone response to a Ca- and P-enriched titanium surface obtained by anodization

This study evaluated bone response to a Ca- and P- enriched titanium (Ti) surface treated by a multiphase anodic spark deposition coating (BSP-AK). Two mongrel dogs received bilateral implantation of 3 Ti cylinders (4.1 x 12 mm) in the humerus, being either BSP-AK treated or untreated (machined - control). At 8 weeks postimplantation, bone fragments containing the implants were harvested and processed for histologic and histomorphometric analyses. Bone formation was observed in cortical area and towards the medullary canal associated to approximately 1/3 of implant extension. In most cases, in the medullary area, collagen fiber bundles were detected adjacent and oriented parallel to Ti surfaces. Such connective tissue formation exhibited focal areas of mineralized matrix lined by active osteoblasts. The mean percentages of bone-to-implant contact were 2.3 (0.0-7.2 range) for BSP-AK and 0.4 (0.0-1.3 range) for control. Although the Mann-Whitney test did not detect statistically significant differences between groups, these results indicate a trend of BSP-AK treated surfaces to support contact osteogenesis in an experimental model that produces low bone-to-implant contact values.

O objetivo desse estudo foi avaliar a resposta do tecido ósseo à superfície de titânio (Ti) enriquecida com Ca e P obtida por anodização (BSP-AK). Três cilindros de Ti (4,1 x 12 mm) BSP-AK ou usinado (controle) foram implantados bilateralmente nos úmeros de dois cães de raça indefinida. Oito semanas após a implantação, os fragmentos ósseos contendo os implantes foram removidos e processados para análises histológica e histomorfométrica. A formação óssea foi observada na região cortical e no canal medular até aproximadamente um terço da extensão do implante. Na maioria dos casos, feixes de fibras colágenas dispostos paralelamente à superfície do implante foram observados na região medular. Nessa região observaram-se também áreas focais de formação de matriz mineralizada e osteoblastos ativos. Os implantes do grupo BSP-AK apresentaram média de contato osso-implante 2,3 por cento, com medidas variando de 0,0 a 7,2 por cento e os do grupo controle tiveram média 0,4 por cento, com medidas variando de 0,0 a 1,3 por cento. Apesar do teste de Mann-Whitney não mostrar diferença estatisticamente significante entre os grupos, nossos resultados indicaram uma tendência para a ocorrência de osteogênese de contato na superfície BSP-AK em um modelo experimental que resulta em baixos valores de contato osso-implante.

Undiffentiated Carcinoma with Osteoclast-like Giant Cells of the Pancreas / 대한소화기학회지

Undifferentiated carcinoma with osteoclast-like giant cells is a rare neoplasm of exocrine pancreas. Till recently, some cases have been reported, however histogenesis of the tumors are controversial and their characteristic findings have not been described yet. Thirty five-year-old men and 75-year-old men were presented with upper abdominal pain and a palpable mass. On computed tomography, one case showed a well enhancing solid tumor with low density and the other was showed a mainly cystic tumor with peripheral enhancement in the body and tail of the pancreas. One case accompanied multiple metastatic liver masses with subhepatic lymph node enlargement. Tumor staining was seen on angiography. Biopsy and pancreatectomy were performed. Pathological findings revealed tumors composed of neoplastic spindle shaped or pleomorphic large cells with scattered non-neoplastic osteoclast-like giant cells. In one case, there were small foci of adenocarcinoma components in the periphery of the tumor. On immunohistochemical stain, neoplastic cells showed focal positivity for epithelial membrane antigen and vimentin. Tumors were diagnosed as undifferented carcinoma with osteoclast-like giant cells. We report these rare cases with a review of literature.