问题
单项选择题 A1型题
临床上，经过治疗也不能保存的年轻第一恒磨牙最佳拔除时间范围宜在（）。
A.6～8岁
B.8～10岁
C.10～12岁
D.12～14岁
E.15岁以上
答案
参考答案：B
解析：第一恒磨牙如过早拔除使对牙伸长，可引起咬合关系错乱；过晚拔除，第二恒磨牙将难以整体向前移动，只能造成牙冠向近中倾斜，同样造成咬合关系不良，因此拔牙时期最好选择在8～9岁为宜，故选B。
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