Deposits of plaque build up between the tooth and the gum.

牙菌斑的沉积物在牙齿和牙龈间形成。

《柯林斯英汉双解大词典》

Plaque is always forming on the teeth, especially at the gum line.

牙菌斑往往长在牙齿上，特别是在牙龈线上。

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If plaque is not removed, it builds up and gets under the gum line.

如果不清除牙菌斑，它就会堆积起来并钻到牙龈下面。

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And removal is called for in cases where fluid collects around a wisdom tooth that is partly or fully below the gum.

VOA: special.2011.08.10

It's providing a means of deciding where the gum has decayed.

提供了决定牙周炎在哪恶化的手段。

耶鲁公开课 - 死亡课程节选

"This is a gum ball, same shape and size, poses the same threat to a child's airway.

VOA: standard.2010.02.23

You have the store right in front of where the gum tree used to be?

NPR: Philadelphia's Gum Tree Cut Down

Nestle remains cautious about the funds being pumped into research by the gum industry.

CNN: Chew on this: Gum may be good for body, mind

In 1848, feather balls were replaced by gutta-percha balls made from the gum of a Malaysian tree.

WSJ: Collecting: Mementos of a Gentleman's Game | The Jaime Ortiz-Pati?o Collection