O reparo ósseo de alvéolos após exodontia dos molares superiores em um modelo animal em ratos Wistar (Rattus norvegicus, albinus) de osteonecrose dos maxilares associada ao uso de bisfosfonatos foi avaliado através de analise microscópica e molecular. Foram utilizados 48 ratos (Rattus norvegicus, albinus, Wistar) machos, com 12 semanas de vida e peso aproximado de 300 gramas, que foram dividos em 4 grupos. Cada grupo era composto por 12 animais, sendo 2 grupos experimentais AZ e AZ-Cirúrgico (AZ-C), que foram submetidos a administração de ácido zoledrônico, 0,6 mg/kg a cada 28 dias com um total de 5 doses e 2 grupos controles CO e CO-Cirúrgico (CO-C) com administração de cloreto de sódio 0,9% no mesmo volume e frequencia do ácido zoledrônico. Todas as soluções foram administradas por via intraperitoneal. O grupo AZ-C e o grupo CO-C foram submetidos a exodontia do primeiro, segundo e terceiro molares superiores 45 dias após a primeira aplicação das soluções. Todos os animais foram eutanasiados após 150 dias do início do experimento (105 dias após as exodontias). As maxilas dos animais foram avaliadas macroscopicamente para presença de lesões espontâneas e com uma sonda clinica número 5 as regiões das exodontias dos molares foram avaliadas para presença ou ausência de solução continua do epitélio. Após feita a avaliação macroscópica as regiões das exodontias dos molares superior esquerdo e do lado contralateral de cada animal foram submetidas a análises qualitativa e quantitativa para presença de sequestros ósseos, restos radiculares, área de osteonecrose, área de espaço trabecular, área de reação periosteal, através de estudos por microscopia óptica pela coloração Hematoxilina e Eosina. Análise quantitativa da expressão do RNAm de proteínas envolvidas no processo de reparo ósseo RANK, RANKL, OPG e VEGF, pelo método de reação em cadeia da polimerase em tempo real (RealTimePCR) também foi realizada. A avaliação macroscópica mostrou que 91,66% dos animais do grupo AZ-C e 41,66% do grupo CO-C apresentaram solução de continuidade do epitélio, sendo estatisticamente significante maior no grupo em terapia com ácido zoledrônico pelo este exato de Fischer (p<0,05). Todos animais do grupo AZ-C e nenhum do grupo CO-C apresentaram sequestros ósseos e todos os animais apresentaram presença de restos radiculares na análise microscópica. A área de osteonecrose foi maior nos animais do grupo AZ-C do que no grupo CO-C (p<0,005), não havendo diferença estatística entre as áreas de espaço trabecular, reação periosteal e osso total. Na análise molecular de RANK, RANKL, OPG e VEGF não houve diferença estatisticamente significante entre os grupos CO, AZ, COC e AZ-C, mesmo quando comparadas áreas de exodontia com áreas com dentes. Estes resultados levam a conclusão que o modelo animal utilizado no presente estudo é um modelo seguro, que o ácido zoledrônico interferiu no reparo ósseo dos alvéolos, causando um atraso na remodelação óssea da região e uma maior incidência de osteonecrose e sequestros ósseos. O ácido zoledrônico não afetou a expressão de RANK, RANKL, OPG e VEGF 105 dias após as exodontias. / The alveolar bone repair following extraction of maxillary molars in an animal model of bisphosphonate related osteonecrosis of the jaws in Wistar rats (Rattus norvegicus, Albinus) was assessed through microscopic and molecular analysis. A total of 48 rats (Rattus norvegicus, Albinus, Wistar rats) with 12 weeks old and weighing approximately 300 grams were used, they were divided into 4 groups. Each group consisted of 12 animals, with 2 experimental groups AZ and AZ-Cirúrgico (AZ-C), who underwent the administration of zoledronic acid, 0.6 mg / kg every 28 days with a total of 5 doses. And 2 control groups CO and CO-Cirúrgico (CO-C) with administration of sodium chloride at 0.9% in the same volume and frequency of zoledronic acid. All solutions were administered intraperitoneally. The group AZ-C and CO-C underwent to extraction of the first, second and third molars 45 days after the first application of the solutions. All animals were sacrificed after 150 days from the beginning of the experiment (105 days after extractions). The maxilla of the animals were assessed macroscopically for the presence of spontaneous lesions, and with a clinical probe number five the regions of the molar extractions were evaluated for the presence or absence of loss of continuity of the oral epithelium. After macroscopic evaluation, the upper left molar and contralateral side of the extraction regions of each animal were submitted to qualitative and quantitative analyzes for the presence of bone sequestrum, root fragments, osteonecrosis area, trabecular space area, area of periosteal reaction, through optical microscopic studies by hematoxylin and eosin staining. And quantitative analysis of mRNA expression of proteins involved in bone repair (RANK, RANKL, OPG and VEGF), by the method of RealTimePCR were carried out. Macroscopic evaluation showed that 91.66% of the AZ -C group and 41.66% of the CO-C group presented a loss of continuity of the epithelium, which was statistically significant higher in the zoledronic acid group according to the Fisher test (p<0.05). All animals in group AZ-C and none in CO-C group showed bone sequestrum and all animals in both groups had root fragments in microscopic analysis. The area of osteonecrosis was higher in the animals of AZ-C group than in CO-C (p<0.005), with no statistical difference between the areas of trabecular space, periosteal reaction and total bone. In the molecular analysis of RANK, RANKL, OPG e VEGF there was no statistically significant difference between the CO, AZ, CO-C e AZ-C groups, even when extraction regions were compared to non extractions areas. These results lead to the conclusion that the animal model described used in this study is a reliable model and zoledronic acid interferes with alveolar bone repair causing a delay in bone emodeling and a higher incidence of osteonecrosis and bone sequestrum. Zoledronic acid did not affect the expression of RANK, RANKL, OPG and VEGF 105 days after dental extractions.

O uso de ciclosporina A (CsA) tem sido associado com aumento na reabsorção óssea como efeito adverso. Porém, há controvérsia sobre quais mecanismos são responsáveis por esta associação. Objetivo: Este estudo investigou o efeito da exposição prévia a CsA sobre a expressão de RANK e perda óssea na periodontite experimental em ratos. Método: Quarenta ratos Wistar, com aproximadamente três semanas de idade, foram divididos em quatro grupos com dez animais cada: Grupo Controle (GC); Grupo CsA (GCsA), Grupo Ligadura (GL) e Grupo Ligadura e CsA (GCsAL). GCsA e GCsAL receberam doses diárias de CsA (10mg / kg) durante sessenta dias desde o início do experimento. Em GL e GCsAL, a ligadura foi colocada em torno do segundo molar superior direito, trinta dias após o início do experimento. Após sessenta dias os animais foram eutanasiados por perfusão cardíaca e as maxilas foram removidas e processadas para análise imunohistoquímica e histomorfométrica da remodelação óssea através da expressão da marcação do RANK (escore) e perda óssea mensurada da junção cemento-esmalte à crista óssea (&#956;m). Os dados foram analisados por Kruskal-Wallis ao nível de 5% de significância. Resultados: Os resultados da marcação de RANK não apresentaram diferença estatística significativa entre os grupos (p=0,122). Em relação à perda óssea, não foi observada influência significativa quanto à aplicação da CsA. GL (735,88 121,82) apresentou perda óssea significativamente superior (p=0,01) a GC (569,13 89,76) e, GCsAL (759,38 198,23) superior (0,001) a GCsA (410,90 105,95). Conclusão: Os resultados sugerem que a exposição prévia a CsA não influenciou a expressão de RANK ou a perda óssea na periodontite experimental em ratos. / The use of cyclosporin A (CsA) has been associated with increased bone resorption as adverse effect. However the mechanisms responsible for this association remains controversy. Aim: The study investigated the effect of prior exposure to CsA on expression of RANK and bone loss in experimental periodontitis in rats. Methods: Forty Wistar rats were divided into four groups with ten animals each: Control Group (CG) CsA group (GCsA), Group Ligation (GL) and Group ligated and CsA (GCsAL). GCsA and GCsAL received daily doses of CsA (10mg / kg) for sixty days from in the beginning of the experiment. In GL and GCsAL, ligature was placed around the upper right second molar, thirty days after in the beginning of the experiment. After sixty days the animals were euthanized by cardiac perfusion and the jaws were removed and processed for immunohistochemistry and histomorphometric analysis of bone remodeling through the expression of RANK marking (score) and bone loss measured from the cemento-enamel junction to bone crest (mm). Data were analyzed by Kruskal-Wallis test at 5% significance level. Results: The results of the marking of RANK showed no statistically significant difference between groups (p = 0.122). In relation to bone loss, there was no significant influence on the application of CsA. GL (735.88 121.82) had significantly higher bone loss (p = 0.01) GC (569.13 89.76) and GCsAL (759.38 198.23) higher (0.001) GCsA (410.90 105.95). Conclusions: The results suggest that prior exposure to CsA did not influence the expression of RANK in bone loss or periodontitis in rats.

Orientadores: Francisco Humberto Nociti Junior, Enilson Antonio Sallum / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-04T03:59:16Z (GMT). No. of bitstreams: 1 Menezes_JulianaBezerraSaldanha_D.pdf: 805559 bytes, checksum: eb703f4648ccb1fb4eeab1900b79a4aa (MD5) Previous issue date: 2005 / Resumo: O objetivo do presente estudo foi avaliar a influência do consumo de cigarros sobre as alterações dimensionais que ocorrem no rebordo alveolar após a extração dentária. Foram selecionados 21 pacientes, com extrações indicadas de elementos anteriores na maxila, por causas periodontais, fraturas ou presença de cáries. Cada participante foi designado para um dos seguintes grupos: grupo 1 (n=11)- não fumantes ou grupo 2 (n=10)-pacientes que fumam um mínimo de 10 cigarros/dia. No período máximo até 7 dias após a extração, os participantes foram submetidos a uma tomografia linear, para determinação da altura e da largura do rebordo alveolar, e a uma radiografia periapical, para cada dente extraído, que foi utilizada para determinação da densidade radiográfica. Os parâmetros foram reavaliados com 6 meses após a extração. A análise intragrupos (teste t-pareado) revelou uma redução estatisticamente significante para o parâmetro altura óssea, no grupo dos não-fumantes (P=0,019) e dos fumantes (P<0,001), entretanto quando as médias de altura dos dois grupos foram comparadas entre si, não houve diferença estatística, em nenhum dos tempos avaliados (teste-t). Para os parâmetros de largura média e coronária, apenas o grupo dos fumantes apresentou uma redução significante do início aos 6 meses do experimento. A densidade radiográfica no centro do alvéolo diferiu estatisticamente, no grupo dos fumantes, na análise intragrupo (P=0,011) e intergrupos (P=0,006), na reavaliação. As análises intergrupos, nos dois períodos de avaliação, apresentaram médias de densidade radiográfica do osso íntegro significativamente inferiores, no grupo dos fumantes. Dentro dos limites do presente estudo, pode-se concluir que o consumo de cigarros influencia negativamente o processo de remodelação do rebordo alveolar pós-extração / Abstract: The aim of the present study was to radiographically evaluate the effect of cigarette smoking on dimensional alveolar bone changes following teeth extraction. Twenty-one subjects were included and designated to one of the groups, regarding their smoking status: group 1(n=11)- non-smoking and group 2 (n=10)- smoking. After tooth extraction, linear tomography images and conventional periapical radiographs were taken to evaluate the following parameters: height, width and density of alveolar ridge. The radiographic examinations were repeated after six months. The intragroup analysis (paired t-test) demonstrated statistically significant difference for the bone height in smokers (P<0,001) and non-smokers (P=0,019), although no differences were noted between smokers and non-smokers (P> 0,05). The smoking group experienced a significant loss in bone width, in the middle (P=0,009) and coronary (P<0,001) region of the alveolar ridge, over six months. The radiographic density of the socket area in smokers was statistically lower than in non-smokers, after six months (P=0,006). In addition, smokers experienced a radiographic density loss over six months (P=0,011). The radiographic density in a well-defined area apical to the socket was also statistically significant different between smokers and non-smokers at baseline (P=0,036) and after 6 months (P=0,023). Within the limits of the present study, it was concluded that cigarette smoking may negatively influence the alveolar ridge remodeling after tooth extraction / Doutorado / Periodontia / Doutor em Clínica Odontológica

La malposición dentaria influye en la estética y funcionalidad de los pacientes. Ante esta situación, es posible realizar la corrección mediante el tratamiento ortodóntico fijo; sin embargo, a la consulta, acuden pacientes con características clínicas tales como corticales vestibulares reducidas, reabsorciones radiculares y posiciones de las piezas dentarias no compatibles con el hueso alveolar, los cuáles limitan la posibilidad de alcanzar los objetivos del tratamiento ortodóntico. A pesar de esto, es posible complementar el tratamiento ortodóntico con procedimientos periodontales para optimizar el movimiento dental y reducir efectos adversos en los tejidos de soporte. Este trabajo reporta el tratamiento ortodóntico realizado en seis meses de un paciente de sexo femenino de 25 de edad complementado con corticotomía e injerto óseo para corregir el apiñamiento de las piezas dentarias sin efectos adversos de los tejidos de soporte. Es recomendable contar con un análisis tomográfico previo al tratamiento para poder evaluar correctamente la topográfica del hueso alveolar, de tal forma que se puedan identificar factores que puedan alterar la estabilidad del tratamiento ortodóntico. / Dental malposition influences the aesthetics and functionality of patients. In this situation, it is possible to make the correction by means of fixed orthodontic treatment; However, at the consultation, patients with clinical features such as reduced vestibular cortices, root resorption and positions of teeth not compatible with alveolar bone, which limit the possibility of achieving the objectives of orthodontic treatment. Despite this, it is possible to complement orthodontic treatment with periodontal procedures to optimize dental movement and reduce adverse effects on supportive tissues. This work reports the orthodontic treatment performed in six months of a 25-year-old female patient supplemented with corticotomy and bone graft to correct the crowding of the dental pieces without adverse effects of the support tissues. It is advisable to have a tomographic analysis prior to treatment in order to correctly assess the topography of the alveolar bone, so that factors that can alter the stability of the orthodontic treatment can be identified. / Trabajo académico

OBJECTIVE: To determine the effects of vitamin C and insulin on osteoblasts harvested from neonatal mouse calvaria. To determine the effects of experimental media (vitamin C and insulin and a combination) on the ex-vivo live bone organ culture model and explore the capacity of addition of osteoblasts to allow for bone formation within a critical defect. To use the chick chorioallantoic membrane (CAM) model to explore bone formation within critical bone defect. METHODS: Osteoblasts were harvested from neonatal mice were tested using four types of experimental media: control DMEM, media prepared with 150 μg/ml vitamin C, 10 nM media, or a combination of both vitamin C, insulin, and a combination of vitamin C and insulin media. Cell were cultured for 18 days at 37°C. Neutral red was done to identify cellular activity and silver nitrate to detect calcium deposits. Two types of scaffolds were inserted into the defect: collagen membrane scaffold and NuOss (xenograft) with collagen scaffold. After 30 days the samples were collected for histological analysis. Neonatal mouse calvaria were harvested and a 2mm critical defect made on each calvaria. Each calvaria received a scaffold of collagen or NuOss with or without osteoblasts with one of three experimental media within the CAM model. After 7 days, the amnion membrane of the egg was dropped and a window was made. The calvaria with the scaffold samples were placed on the amnion membrane. The eggs were incubated for 10 days then the experiment was terminated. Calvaria were collected and processed for histological evaluation. RESULTS: Neutral red and silver nitrate of 2D in-vitro cells revealed calcium deposits in culture well using vitamin C media, cell cultured with insulin media showed calcium deposits and cell morphological change, and cell cultured with a combination of vitamin C and insulin media showed the most calcium deposits and morphological changed. Ex-Vivo samples with collagen scaffold had bone thickening but not enough nutrients for bone regeneration, despite the addition of cells. The collagen scaffold is a more suitable material than xenograft due to particle size. The CAM model showed new bone formation and new vessels were most abundant in areas closest to lining cells in collagen samples. Samples with additional osteoblasts added showed greater results. NuOss scaffold samples did not show the same bone formation or vessel growth. CONCLUSIONS: The results indicate and confirm the basic principles of tissue engineering. In order to have bone regeneration more cells allow for better results. The quality of the scaffold is important and should have stability as well as enough space for cellular migration and recruitment for new blood vessel to support regeneration of bone to its original state.

ABSTRACT A Study of Osteocyte Apoptosis by Region and Quadrant in Murine Cortical Bone Jessica Kristen Chan Osteocytes undergo apoptosis to spatially and temporally initiate bone remodeling. This study investigates the distribution of apoptotic osteocytes within different quadrants and regions of cortical bone and compares the frequency of osteocyte apoptosis to regional factors associated with bone remodeling. Specifically, the quantity of apoptosis was compared to levels of the bone morphagenic protein antagonists noggin and gremlin. Samples of unloaded right tibial bone obtained from C57/Bl/6 mice underwent TUNEL staining for apoptotic osteocytes and were counterstained with methyl green to detect osteocyte viability. Cross sectional areas of bone were divided into four quadrants (cranial, caudal, medial, and lateral) and three regions (proximal, midshaft, and distal) for analysis. Densities and percentages of osteocytes were measured within each area. While the results show that there were no differences among quadrants, regional variations were found in osteocyte apoptosis. A significantly higher density of apoptotic osteocytes was found in the midshaft region which also displayed higher levels of BMP antagonists. Using regression analysis, a positive linear relationship between apoptotic osteocytes and gremlin was established while noggin showed a negative linear correlation for the percentage of apoptotic osteocytes. Further studies are needed to observe the distribution of apoptotic osteocytes within loaded bone to confirm the exact relationship between osteocyte apoptosis and bone remodeling. Keywords: osteocyte apoptosis, bone remodeling

The purpose of this study is to characterize the compact bone remodeling of the ovariectomized ewe and its effectiveness as an animal model for studies of postmenopausal osteoporosis. The use of animal models is a beneficial way to evaluate the effectiveness of medical devices and therapeutic agents for treating diseases. The ovine model is an attractive option because of its large size and similar bone remodeling to humans. However, this species, like most animals, does not undergo a natural menopause, making an ovariectomy necessary for studies of estrogen depletion. The OVX (ovariectomized) sheep has been widely accepted as a model for loss of BMD. However, even with its advantages seasonality has been shown to have an effect on the bone remodeling in the ovine model. Thus, this study focused on characterizing the seasonal and anatomical variation in the compact bone remodeling in the ovine model. In doing so, 28 skeletally mature Columbia-Rambouillet cross ewes underwent an ovariectomy. The animals were divided into groups of 7 based on each season: autumn, winter, spring, and summer. During its specified season each group of 7 underwent ovariectomy and then was sacrificed 12 months post-surgery. The radii and ulnae were harvested and then divided into 6 anatomical locations: craniolateral, cranial, craniomedial, craniolateral, caudal, and caudomedial. This allowed for analysis through the fabrication of microradiographs. Histomorphometric analysis involved measurements to quantify the bone volume to tissue volume ratio, the percent of tissue and material remodeling, the mean secondary osteonal radius, and number of tissue and material cement line interfaces. Densitometry analysis was then performed to determine the density of each sector relative to an aluminum step wedge, serving as the key. Using a 2-way repeated measures ANOVA statistical analysis was performed to evaluate for seasonal and anatomical differences as well as a possible interaction between season and anatomical region. The OVX data showed significant seasonal and anatomical differences as well as seasonality within anatomical section in the remodeling parameters. When this data was combined with earlier data from a control, sham-cohort from the same experiment a 3-way ANOVA was also performed to evaluate the effects of season, anatomical sector, and treatment on the remodeling parameters. Again, there was significant seasonal, anatomical, and treatment differences, as well as interactions of all three. The results of this study showed that varying levels of remodeling occurs in the adult OVX ovine model and differences between the control and OVX model can be attributed to seasonal and anatomical variations. Thus, it will be an important consideration when developing new test protocols for research incorporating the sheep model for studying osteoporosis.

Indiana University-Purdue University Indianapolis (IUPUI) / Bisphosphonates, drugs which inhibit bone resorption and remodeling, are currently prescribed for the treatment of osteoporosis. Previous research suggests that decreased bone turnover may lead to accumulation of microdamage, possibly increasing the risk for fracture in some sites. The effects of bisphosphonate therapy on the mandibular condyle have not been quantitatively studied. The purpose of the proposed study was to histomorphometrically quantify the effects of etidronate (a bisphosphonate) on trabecular bone sites of the dog mandibular condyle and to compare this to another trabecular bone site (vertebrae) to determine whether the two sites were affected differently. Eleven mature female dogs were treated with high- (5 mg/kg/d) and low- (0.5 mg/kg/d) dose etidronate therapy for seven months. Fluorochrome labels were used to mark sites of bone mineralization for the calculation of static and dynamic histomorphometric parameters. High-dose therapy resulted in a complete inhibition of remodeling, as shown by the reduction of mineral apposition rate (MAR), bone formation rate (BFR), and mineralizing surface (MS/BS) to zero. Low-dose therapy also decreased BFR and MS/BS. Osteoid accumulation was only significant in the high-dose therapy group, but there was no evidence of osteomalacia (osteoid volume < 5%). Etidronate treatment had no significant effect on bone volume, trabecular number, trabecular thickness, or trabecular separation. Vertebral trabeculae ranged from 5.5 to 9.5 times greater in number than mandibular trabeculae, but were 45 to 60 percent thinner and closer together. The interaction between dosage and site was insignificant for all parameters studied. Further investigation is needed to determine whether these effects will prove to be harmful to the mandibular condyle, especially over a long period of time.

Indiana University-Purdue University Indianapolis (IUPUI) / Bisphosphonates, effective inhibitors of bone resorption, are used in the treatment of postmenopausal osteoporosis. At present, the effects of bisphosphonate therapy on the maxilla have not been quantitatively studied. As part of the masticatory system, dentate alveolar bone is exposed to a unique pattern of loading. As such, data obtained from bisphosphonate studies of other bones may not be applicable to the cortical bone of the dentate maxilla. The objective of this study is to histomorphometrically quantify the effects of alendronate and risedronate therapy on alveolar bone of the dog maxilla (MX) and to determine if this site is affected differently than the cortical bone in the rib (R) from these same animals. Twenty-two female dogs were divided into three treatment groups of 1 mg/kg/day alendronate, 0.5 mg/kg/day risedronate, and a saline vehicle control. Fluorochrome labels were used to mark sites of bone formation. Maxillary and rib specimens from each dog were prepared for analysis of static and dynamic histomorphometric parameters. MX cortical bone surrounding the third premolar was further analyzed by side (buccal vs. lingual) and region (coronal vs. apical). Mineralizing surface (MS/BS) and bone formation rate (BFR) in the coronal maxilla of the control group is significantly (p < 0.05) higher than that of the bisphosphonate groups. In bisphosphonate treated animals, MS/BS, BFR, and activation frequency (AcF) were significantly (p < 0.05) higher in the R than in the MX. In all treatment groups, very little osteoid was detected, and no significant difference in the mineral apposition rate (MAR) was noted. These results indicate that: (1) bisphosphonate dosages used in this study effectively inhibited remodeling within the dog maxilla; (2) alveolar bone remodeling was decreased more than remodeling in rib cortical bone; (3) within the dentate maxilla, alveolar bone remodeling was decreased more in the coronal than in the apical region, and (4) none of the groups appears to show inhibition of mineralization.

No description available.