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The aim of this work was to analyse the behaviour of the dental lamina during the development process of first molar teeth. The offspring of female mice were analysed at the 16th day of intra-uterine life and since birth till 17 days old with the aim to evaluate the dental lamina evolution of upper and lower first molars. The animals were sacrificed, and the heads embedded in paraffin in order to get frontal or sagittal sections whose were stained by hematoxylin and eosin method. The results showed a very clear presence of the dental lamina in all periods under analysis, without the occurrence of its disorganization, in other words, it was permanently connecting the developing tooth germ to the oral epithelium until advanced dental eruption.

Made available in DSpace on 2021-07-14T10:44:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2008. Added 1 bitstream(s) on 2021-07-14T11:37:16Z : No. of bitstreams: 1 S0103-64402008000100007.pdf: 5061182 bytes, checksum: 195bbfb78f3040f8cf4217fa5c53067b (MD5) O objetivo deste estudo foi avaliar histologicamente o efeito da associação do formocresol com endotoxina (LPS) em tecido conjuntivo de camundongos. Noventa camundongos foram divididos em três grupos de 30 camundongos cada. Cada camundongo recebeu um implante subcutâneo de tubo plástico contendo solução de endotoxina (10 mg/ml), formocresol (fórmula original), ou uma mistura de formocresol com endotoxina. Os grupos da endotoxina e formocresol foram considerados grupos controle. Os períodos de análise foram 7, 15 e 30 dias. Após os períodos experimentais, os tecidos foram removidos e submetidos a processamento histológico. Os resultados obtidos indicam que a endotoxina e o formocresol produzem necrose e inflamação tecidual crônica aos 7 e 15 dias e aos 30 dias o grupo da endotoxina não mostrava necrose e no grupo do formocresol a necrose persistiu. A combinação formocresol e endotoxina mostrou necrose e inflamação crônica com resultados semelhantes ao do grupo formocresol para todos os períodos experimentais. Pode-se concluir que o formocresol parece não ser capaz de inativar os efeitos tóxicos da endotoxina. This study performed a histological analysis of the effect of formocresol associated to endotoxin (LPS) in the subcutaneous connective tissue of mice. Ninety mice were randomly assigned to 3 groups (n=30). Each animal received one plastic tube implant containing endotoxin solution (10 mg/mL), formocresol (original formula) or a mixture of endotoxin and formocresol. The endotoxin and formocresol groups served as controls. The periods of analysis were 7, 15 and 30 days. At each experimental period, tissue samples were collected and submitted to routine processing for histological analysis. Endotoxin and formocresol produced necrosis and chronic inflammation at 7 and 15 days. At 30 days, the endotoxin group showed no necrosis, while in the formocresol group necrosis persisted. The formocresol-endotoxin association produced necrosis and chronic inflammation in the same way as observed with formocresol at all experimental periods. In conclusion, formocresol seems not to be able to inactive the toxic effects of endotoxin in connective tissues. Universidade Estadual Paulista, School of Dentistry of Araraquara Universidade Estadual Paulista, School of Dentistry of Araraquara