十 二歲以上的小朋友也開始進入青春期，此時期大部乳齒已經脫落而換成永久齒，顎骨的生長也達到了高峰，臉部美觀問題這時也會被考慮與處理，很多小朋友在此時 期開始進行全口矯正治療。此時期的小朋友如果有口腔不良習慣，還是得要改正，若是沒有改正口腔不良習慣，全口矯正將牙齒排列整齊的成果就很難維持。

Children start to enter puberty after turning 12. During this period most of the baby teeth have shed and been replaced with permanent teeth. Mandibular bone development has reached its height and issues with facial esthetics should be considered and treated. Many children begin to undergo full-mouth orthodontic treatment at this time. If there are any inappropriate dental habits, this is time to be corrected. If not, the results of full-mouth orthodontic treatment will be hard to maintain.