Avaliação da influência da osteoporose induzida em ratas, e seu tratamento com alendronato e estrógeno, sobre o tecido ósseo ao redor de implantes
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Data
2010-05-17
Autores
Giro, Gabriela [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O presente projeto teve como objetivo avaliar a influência da deficiência de estrógeno, e as implicações dos tratamentos com alendronato e estrógeno, sobre o tecido ósseo ao redor de implantes. Para isso foram realizados dois estudos distintos, visando elucidar as questões em torno desse tema. No primeiro estudo, foram utilizadas ratas Wistar, com idade aproximada de 60 dias, submetidas à colocação de um implante na metáfise tibial com o objetivo de avaliar a influência da deficiência estrogênica e dos tratamentos com alendronato e estrógeno sobre o tecido ósseo em implantes que já se encontravam osseointegrados. Os resultados mostraram efeitos deletérios da referida deficiência, com diminuição da força de torque necessária para remoção dos implantes, menor quantidade de osso em contato com a superfície e área de osso entre as roscas, aumento nos marcadores de remodelação óssea e menor taxa de aposição mineral no período avaliado. Por outro lado, os animais que receberam a administração do alendronato apresentaram os melhores resultados para todas as análises realizadas, apesar do tecido ósseo mostrar-se mais compacto e sem sinais de remodelação. Concluiu-se que a deficiência estrogênica decorrente da ovariectomia (OVX) acarretou alterações sistêmicas, como perda de massa óssea, e alterou as características do tecido ósseo ao redor dos implantes. Esse quadro pôde ser revertido com os tratamentos instituídos, tendo o alendronato apresentado os melhores resultados. O segundo estudo visou avaliar os efeitos da deficiência de estrógeno e de diferentes dosagens de alendronato, sobre implantes instalados na maxila de ratas e, portanto, sob influência da carga mastigatória. Nesse estudo foram avaliadas também as implicações da instalação de implantes em animais que estavam sob terapia...
This study aimed the evaluation of the influence of bone mass loss and its therapies on bone tissue around osseointegrated implants. For that reason two major projects were conducted. First of all, two implants were placed in 66 female rats tibiae. The animals were assigned to 5 groups: control (CTL), sham, ovariectomy (OVX), oestrogen (EST) and alendronate (ALE). While CTL was sacrificed 60 days after implant placement, other groups were subjected to ovariectomy or sham surgery according to group and euthanized after 90 days. Blood and urine samples were collected at sacrifice day for osteocalcin and deoxypyridinoline quantification. Densitometry of femur and lumbar vertebrae were performed in order to evaluate rats’ skeletal impairment. One implant was subjected to the removal torque test, while the remaining one was referred to non-decalcified sections and analysed by fluorescent and light microscopy for analyses of mineral apposition rate (MAR), eroded and osteoclastic surfaces, bone to implant contact (BIC), and bone area fraction occupancy (BAFO). The results of this study showed that OVX presented significantly lower values for all parameters analysed compared to other groups. ALE increased bone mineral density and the removal torque of the implants, but also reduced osteocalcin and deoxypyridinoline concentrations, MAR, osteoclastic and eroded surfaces, and no difference was in BIC and BAFO relative to SHAM. EST and CTL showed similar results to SHAM for measurements. The results lead the authors to conclude that oestrogen deficiency exerted a negative influence on bone tissue around implants, while oestrogen replacement therapy and alendronate were effective against its effects. Although alendronate therapy maintained the amount of bone tissue around implants, studies evaluating bone turnover kinetics ... (Complete abstract, click electronic access below)
This study aimed the evaluation of the influence of bone mass loss and its therapies on bone tissue around osseointegrated implants. For that reason two major projects were conducted. First of all, two implants were placed in 66 female rats tibiae. The animals were assigned to 5 groups: control (CTL), sham, ovariectomy (OVX), oestrogen (EST) and alendronate (ALE). While CTL was sacrificed 60 days after implant placement, other groups were subjected to ovariectomy or sham surgery according to group and euthanized after 90 days. Blood and urine samples were collected at sacrifice day for osteocalcin and deoxypyridinoline quantification. Densitometry of femur and lumbar vertebrae were performed in order to evaluate rats’ skeletal impairment. One implant was subjected to the removal torque test, while the remaining one was referred to non-decalcified sections and analysed by fluorescent and light microscopy for analyses of mineral apposition rate (MAR), eroded and osteoclastic surfaces, bone to implant contact (BIC), and bone area fraction occupancy (BAFO). The results of this study showed that OVX presented significantly lower values for all parameters analysed compared to other groups. ALE increased bone mineral density and the removal torque of the implants, but also reduced osteocalcin and deoxypyridinoline concentrations, MAR, osteoclastic and eroded surfaces, and no difference was in BIC and BAFO relative to SHAM. EST and CTL showed similar results to SHAM for measurements. The results lead the authors to conclude that oestrogen deficiency exerted a negative influence on bone tissue around implants, while oestrogen replacement therapy and alendronate were effective against its effects. Although alendronate therapy maintained the amount of bone tissue around implants, studies evaluating bone turnover kinetics ... (Complete abstract, click electronic access below)
Descrição
Palavras-chave
Implantes dentários, Osteoporose, Ovariectomia, Alendronato, Difosfonatos, Terapia de reposição hormonal, Ovariectomy, Osteoporosis, Dental implants, Alendronate, Bisphosphonate, Rats
Como citar
GIRO, Gabriela. Avaliação da influência da osteoporose induzida em ratas, e seu tratamento com alendronato e estrógeno, sobre o tecido ósseo ao redor de implantes. 2010. 236 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Odontologia de Araraquara, 2010.