There are four premolars on top and four on the bottom.

上颚有四颗前磨牙，下颚有四颗。

Those fed softer food had more crowded premolars, rotated or displaced teeth, and narrower dental arches.

吃较软食物的松鼠猴，前臼齿会比较拥挤，更多转向或移位的牙齿，牙弓更狭窄。

Baby molar teeth are replaced by adult premolars.

婴儿的磨牙被成人的前磨牙取代。

Unlike its ancestors, Archaeocyon had shorter jaws and thicker premolars.

与其祖先不同，古龙的下颚较短，前臼齿较厚。

While many therapsids have premolars and molars, this one didn't.

虽然许多兽孔目动物有前臼齿和臼齿，但这个没有。

Infants and young children do not have premolars because these teeth do not start to come in until around age 10.

婴幼儿没有前磨牙，因为这些牙齿直到 10 岁左右才开始长出来。

But the fact that they had a few extra premolar teeth suggests their diet  might have included some plant matter.

但事实上，他们有一些额外的前臼齿，这表明他们的饮食可能包括一些植物物质。

Causes It is caused by dental infection or tooth abscess, involving molars and premolars, as well as submandibular sialadenitis, injuries to oral mucosa, and mandibular fracture.

病因原因是牙齿感染或牙齿脓肿，累及磨牙和前磨牙，同时伴有下颌下涎腺炎、口腔黏膜损伤和下颌骨折。

Most adults have 32 teeth called permanent or secondary teeth; 8 incisors, 4 canines, also called cuspids, 8 premolars, also called bicuspids, 12 molars, including 4 wisdom teeth whereas children have 20 teeth.

大多数成年人有 32 颗牙齿，称为恒牙或副牙；8 颗门牙，4 颗尖牙也叫犬牙，8 颗前磨牙，也称为双尖牙，12 颗臼齿，包括 4 颗智齿，而儿童有 20 颗牙齿。

You can feel in your own mouth the sharp tearing teeth of your canines and premolars, while your molars are relatively flat, and can be used for grinding plant material.

您可以在自己的嘴里感觉到犬齿和前臼齿锋利的撕裂牙齿，而您的臼齿相对平坦，可用于研磨植物材料。