Thesis (doctoral)--University of Lund. / "Also published in Odontologisk Tidskrift, Scandinavian Dental Journal no.4/5 v.76."

Thesis (doctoral)--University of Lund. / "Also published in Odontologisk Tidskrift, Scandinavian Dental Journal no.4/5 v.76."

Orientador: Marcelo Rocha Marques / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-17T18:04:39Z (GMT). No. of bitstreams: 1 Guimaraes_GustavoNarvaes_M.pdf: 1921416 bytes, checksum: 319cb7463f7d5db1e0d6718f74a0b426 (MD5) Previous issue date: 2011 / Resumo: A dentina, assim como o osso, é um tecido mineralizado de natureza conjuntiva. Embora já tenha sido relatado que o hormônio paratireóideo (PTH), um dos reguladores da homeostasia do cálcio, participe do processo de formação de dentina, a maioria dos trabalhos envolvendo este hormônio é relacionado ao tecido ósseo. Tal hormônio, que fisiologicamente promove a reabsorção óssea, quando administrado de forma intermitente, pode promover anabolismo ósseo, sendo hoje um dos tratamentos para osteoporose. Por serem ainda pouco conhecidas as funções do PTH na dentinogênese, o objetivo deste estudo foi investigar os efeitos da administração intermitente de PTH sobre a taxa de aposição e características estruturais da dentina em incisivos de camundongos. Para tanto, camundongos A/J Unib foram divididos em quatro grupos: C6, T6, C10 e T10 (n=10). Os animais dos grupos T6 e T10 receberam injeções subcutâneas de 40µg/Kg de hPTH(1-34), durante 6 e 10 dias respectivamente; os dos grupos C6 e C10 receberam injeções subcutâneas do veículo do PTH, também durante 6 e 10 dias respectivamente. Para delimitação da dentina formada no período experimental, os animais dos grupos T6 e C6 receberam injeções intraperitoneais de dois marcadores fluorescentes. Ao término do período experimental, o sangue dos animais dos grupos C6 e T6 foram coletados para quantificação de fosfatase alcalina e, suas hemimandíbulas esquerdas foram removidas para medição das taxas de aposição dentinária. Os animais dos grupos T10 e C10 foram sacrificados e as hemimandíbulas, direita e esquerda, foram processadas para os testes de microdureza knoop da dentina e conteúdo elementar (% de átomos) de cálcio (Ca), fósforo (P), oxigênio (O) e magnésio (Mg) na dentina peritubular e na dentina intertubular por meio da microanálise de energia dispersiva de raios-X (EDX). Após análise estatística pelo teste T de student, verificou-se um aumento significativo de 5% na taxa de aposição de dentina e a análise enzimática detectou um aumento significativo de 25% de fosfatase alcalina no grupo T6 em relação ao grupo C6. Os animais do grupo T10 apresentaram maior (11%) microdureza na dentina do que os animais do grupo C10. A microanálise por EDX demonstrou que o tratamento com PTH (T10) levou ao aumento do conteúdo (% de átomos) de P (23%) e Ca (53%), bem como da relação Ca/P (24%) na dentina peritubular, em relação ao grupo C10 (p<0.01). Estes resultados indicam que a administração intermitente de PTH, teve um efeito anabólico na formação de dentina em camundongos, acompanhado de significativas alterações estruturais na dentina formada / Abstract: Parathyroid hormone (PTH) has been widely studied, especially in the treatment of osteoporosis, since when administered intermittently promotes bone anabolism. Dentin is a mineralized tissue that share certain similarities to the bone. owever, the role of this hormone on dentin formation is poorly known. The purpose f this study was to investigate the effects of intermittent PTH administration on the apposition rate and structural features of dentin from mouse incisors. Forty young male mice A / J Unib were divided into four groups (n = 10): T6 and T10 = animals received subcutaneous injections of 40µg/Kg of hPTH (1-34) diluted in 0.01% acetic acid for 6 and 10 days respectively; C6 and C10 = animals received subcutaneous injections of PTH vehicle, also for 6 and 10 days, which served as control. The animals of C6 and T6 groups received intraperitoneal injections of fluorescent markers for delimitation of dentin formed during the experimental period. Dentin apposition rates, measured by fluorescence microscopy, and the detection of alkaline phosphatase (ALP) plasma levels were evaluated in the animals of T6 and C6 groups. Knoop microhardness testing and element content measurements in atom % of calcium (Ca), phosphorus (P), oxygen (O), and magnesium (Mg) in the peritubular and intertubular dentin by Energy Dispersive ray (EDX) microanalysis via Scanning Electron Microscopy (SEM) were performed in the animals of T10 and C10 groups. Statistical analysis of all tests was completed using unpaired Student's t test (two-tailed). Statistical significance limit was set at 5%, (p<0.05). Histometrical analysis by fluorecence microscopy showed that the animals of T6 group had a significant increase of 5% in the dentin apposition rate when compared with the control animals (C6). In the T6 group, ALP plasma levels were 25% higher than those in the C6 group. The results obtained from the knoop microhardness testing, demonstrated that the animals of T10 group showed greater microhardness than did the control animals (C10) (10%). In addition, EDX microanalysis showed that the P (23%) and Ca (53%) atom % content in the peritubular dentin was increased in the T10 group, compared with C10 group. The Ca/P ratio of T10 animals was also higher than the C10 animals (24%). The chemical composition of intertubular dentin did not differ between the groups. These results indicate that the short-time PTH administration had an anabolic effect on the dentin formation of incisor teeth of young healthy mice; this effect was following by mechanical and composition changes in the dentin / Mestrado / Histologia e Embriologia / Mestre em Biologia Buco-Dental

No description available.

Thesis (doctoral)--University of Göteborg, Sweden, 1981. / Includes bibliographical references.

Thesis (doctoral)--University of Göteborg, Sweden, 1981. / Includes bibliographical references.

Thesis (M.S.)--University of Michigan, 1993.

Healthy tooth formation is crucially dependent on normal development of enamel and dentin. Any deviation from norm could lead to serious effects on the teeth function. Amelogenesis Imperfecta (AI) and Dentinogenesis Imperfecta (DGI) are genetically inherited conditions that affect the teeth formation. Thus is imperative to investigate the genes and proteins that contribute to these conditions. Some of the known proteins that play a role in amelogenesis include AMELOGENIN (AMLEX), KALLIKREIN 4(KLK4), FAMILY WITH SEQUENCE SIMILARITY 83H (FAM83H), WD REPEAT-CONTAINING PROTEIN 72 (WDR72) and DENTIN SIALOPHSOPHPROTEIN (DSPP). The purpose of this research project was to investigate the expression/localization pattern of gene products which are known to be causative for Amelogenesis Imperfecta and Dentinogenesis Imperfecta.The study was carried out using mouse heads which were fixed, demineralized and paraffin-embedded. Samples were then sectioned and immunohistochemical analysis was performed with various enamel/dentin protein antibodies. The data showed the following results: KLK4 showed immunoreactivity mainly in ameloblasts and in the pulp, DSPP showed immunoreactivity in dentin, in the pulp and in the epithelial cells on one location as indicated by the arrow in figure 3 of the tooth cross section, FAM83H has a faint immunoreactivity identified in the ameloblasts, WDR72 showed weak immunoreactivity in the ameloblasts and AMELX showed immunoreactivity on the enamel and the ameloblasts. In conclusion these findings were supported by previous studies and conveyed the validity of IHC experiments in locating these proteins in odontogenic tissues.

Thesis--Göteborg. / Extra t.p. with thesis statement inserted. Includes bibliographical references (p. 27-34).

Thesis--Göteborg. / Extra t.p. with thesis statement inserted. Includes bibliographical references (p. 27-34).