RESUMO
Patients undergoing orthodontic therapy were evaluated for longitudinal changes in relative S. mutans numbers in plaque at discrete sites on the tooth surface associated with direct bond appliances. There was a significant linear increase in the percentage of S. mutans in the total streptococci isolated from the last pre-bracket sample through the last bracket sample.
Assuntos
Placa Dentária/microbiologia , Aparelhos Ortodônticos , Streptococcus mutans/citologia , Adolescente , Criança , Colagem Dentária/métodos , Feminino , Humanos , Masculino , Higiene Bucal , Índice PeriodontalRESUMO
Hypervitaminosis A in treated pregnant rats has been shown to interfere with normal palatal closure and fusion, as demonstrated by the presence of cleft palates in offspring. The observation that palatal shelves of excess vitamin A exposed fetuses are stunted and delayed in rotation suggests that vitamin A may inhibit a biochemical event crucial to the successful contact of the palatal shelves. Maxillary explants from 16 day Wistar rat embryos cultured in the presence or absence of 30 IU/ml retinyl palmitate were analyzed for DNA, glycosaminoglycan, and collagen synthesis. Maxillary explants cultured in vitamin A-containing medium showed an inhibition in DNA, GAG, and collagen synthesis in comparison to control explants. Excess vitamin A in the culture medium of maxillary explants also resulted in a reduction of intermolecular cross-links in collagen. The possible significance of the results in terms of cleft palate and normal secondary palate formation is discussed.
Assuntos
Fissura Palatina/induzido quimicamente , Maxila/embriologia , Vitamina A/efeitos adversos , Animais , Colágeno/biossíntese , Colágeno/fisiologia , Técnicas de Cultura , DNA/biossíntese , Glicosaminoglicanos/biossíntese , Palato/embriologia , RatosRESUMO
References in the endodontic literature specifically warn that orthodontic treatment may initiate the formation of secondary dentin deposition within a tooth to the extent of obstructing the entire root canal. Comparison of forty-six orthodontically treated patients with a control group of age- and sex-matched patients who had not undergone orthodontic treatment revealed two orthodontically treated patients with a total of three teeth that showed evidence of canal calcification. Although this incidence is not statistically significant, the clinical significance of canal calcification in the orthodontic population is discussed.