RESUMO
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.
Assuntos
Dente Serotino/anatomia & histologia , Adolescente , Cefalometria , Criança , Feminino , Humanos , Masculino , Movimento Mesial dos Dentes/diagnóstico , Movimento Mesial dos Dentes/etiologia , Dente Molar/cirurgia , Dente Serotino/diagnóstico por imagem , Radiografia Panorâmica , Extração Dentária/efeitos adversosRESUMO
The angulation of lower third molars is compared in two groups of radiographs of children aged 10.1--13.0 years, one group showing lower second deciduous molars present, the other showing mesial migration of lower first permanent molars and impaction of second premolars following early extraction of lower second deciduous molars. The lower third molar crypts are significantly less tilted in the group where deciduous molars had been removed, the difference between the means of the two groups being 12.5 degrees (p less than 0.001). The findings are discussed in relation to the hypothesis that early mesial migration improves the orientation of third molar crypts by enabling them to develop further forward. There is some evidence that the mean angle of tilt may be reduced by about 20 degrees when mesial migration occurs before third molar crypts begin to form.
