Study On The Relation Between Posterior Arch Spaces And Second Molar Malocclusion

Recently there are more and more dislocation and impaction of the second molar are observed clinically. Since it erupts latter and located posterior of the arch, the orthodontic treatment is much more difficult and may result in longer treatment period. Nowadays researches mainly focus on the clinical treatment and the study of etiological factors, which concerns about the lack of posterior arch spaces, but there is not sufficient experimental evidence to support the hypothesis. Thus we set the study to clear the relation between posterior arch spaces and the second molar malocclusion, i. e. whether the disturbance of the teeth and the bone exists on the patients with second molar malocclusion.Through the clinical investigation of the pre-treatment casts and panoramic radiographs of 5012 cases, we investigate the prevalence of the second molar malocclusions in orthodontic...