n.牙齦

Place the bristles of the brush ninety degrees to the gumline. 刷毛和牙齦緣呈90度。

Gently cleaning between teeth and even below the gumline. 輕柔的清洗牙齒、甚至牙齦的下部。

In addition to loose teeth, infection under the gumline can spread to the liver, kidneys, and heart. 此外松動的牙齒、牙齦的感染很容易導致肝臟、腎臟和心臟的感染。

And dental floss can go where no brush has gone before: between teeth, along the gumline. 而牙線可以進到牙刷不能到達的地方：牙間隙，牙齦邊沿。

Because the edge of the crown extends to or below the gumline, it is critical to keep this area clean and healthy. 因為牙冠的外部一般都到達或在牙齦線下，很有必要保持這部分的清潔與健康。