RESUMO
Introduction: The purpose of this study was to investigate the effect of pregnancy on orthodontic tooth movement in Wistar rats. Material and Methods: Forty eight female three-month old Wistar rats with an average weight of 250±25 gr were selected and randomly divided into two experimental (pregnant) and control groups (non-pregnant). Maxillary central incisors were tipped distally by insertion of springs exerting 30g force. Two, seven and fourteen days after spring insertion animals were sacrificed. Then the mesioincisal distance between maxillary incisors were measured. Subsequently, histological sections were prepared to count osteoclasts under a light microscope. The data on the extent of orthodontic tooth movement, and the number of osteoclasts were analyzed by independent sample t-test. Results: The results indicated that 2,7 and 14 days after force application there was no significant difference inorthodontic tooth movement between experimental and control groups (p>0.05). The number of osteoclasts were significantly lower in the experimental group 7 and 14 days after spring insertion (p<0.05).Conclusion: Pregnancy may decrease the amount of tooth movement in the linear phase but it is not statistically significant. The number of osteoclasts is significantly decreased during pregnancy (AU)
Assuntos
Animais , Feminino , Gravidez , Ratos , Movimento Mesial dos Dentes/diagnóstico , Osteoclastos , Complicações na GravidezRESUMO
The goal of this study is to analyze using structural cephalometric superimpositions the quantity of mesial molar drift in the maximum anchorage cases, with mainly extractions of the first four premolars. Molar anchorage is appreciated in cases treated with or without use of directional forces. The influence of various parameters: age, facial divergence, discrepancy and incisor repositioning, on the loss of anchorage is also evaluated. The statistical study called upon the test of Student for independent groups. A value of the risk of first species p<0.05 was considered as significant. The loss of anchorage seems less important with the use of the directional forces. On the other hand it is raised in teenagers and the cases of important incisor repositioning.
Assuntos
Cefalometria/métodos , Análise do Estresse Dentário , Movimento Mesial dos Dentes/diagnóstico , Procedimentos de Ancoragem Ortodôntica , Adolescente , Adulto , Fatores Etários , Dente Pré-Molar/cirurgia , Criança , Aparelhos de Tração Extrabucal , Feminino , Humanos , Masculino , Movimento Mesial dos Dentes/etiologia , Procedimentos de Ancoragem Ortodôntica/efeitos adversos , Técnica de Subtração , Extração DentáriaRESUMO
The angulation of lower third molars on opposite sides of the jaw was compared on 50 orthopantographic radiographs of children who had mesial migration of lower first permanent molars on one side only following unilateral extraction of lower second deciduous molars. On 36 films the lower third molar was less tilted on the extraction side. Applying a paired t-test this difference is significant (p less than 0.001). The distance of mesial migration was estimated, and the findings are discussed in relation to the hypothesis that early mesial migration of posterior teeth reduces the tilt of lower third molars.
