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

上有四颗磨牙，下有四颗。

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

吃较软食物的松鼠，会比较拥挤，更多转向或移位的牙，牙弓更狭窄。

Baby molar teeth are replaced by adult premolars.

婴儿的磨牙被成人的磨牙取代。

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

与其祖先不同，古龙的下较短，较厚。

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

婴幼儿没有磨牙，因为这些牙直到 10 岁左右才开始长出来。

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

虽然许多兽孔目动物有，但这个没有。

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，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.

病因原因是牙感染或牙脓肿，累及磨牙磨牙，同时伴有下颌下涎腺炎、口腔黏膜损伤下颌骨折。

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，称为恒牙或副牙；8 颗门牙，4 颗尖牙也叫犬牙，8 颗磨牙，也称为双尖牙，12 颗，包括 4 颗智，而儿童有 20 颗牙。

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锋利的撕裂牙，而您的相对平坦，可用于研磨植物材料。

The rest of its dentition was made to shear through flesh, too, like specialized premolars that resembled bolt cutters – kinda like the extreme version of the scissor-like carnassial teeth of carnivorans.

它的其余列也被用来剪断肉，就像专门的， 类似于断线钳——有点像食肉动物剪刀状的食肉牙的极端版本​​。