As early as 4 months, the first primary, or baby, teeth to erupt through the gums are the lower central incisors, followed closely by the upper central incisors.

• 最早在4个月大时，第一颗乳齿或婴儿齿开始从牙龈突出的是下面中间的门牙，紧跟著的是上面中间的门牙。