n.牙龈
Place the bristles of the brush ninety degrees to the gumline. 刷毛和牙龈缘呈90度。
Gently cleaning between teeth and even below the gumline. 轻柔的清洗牙齿、甚至牙龈的下部。
In addition to loose teeth, infection under the gumline can spread to the liver, kidneys, and heart. 此外松动的牙齿、牙龈的感染很容易导致肝脏、肾脏和心脏的感染。
And dental floss can go where no brush has gone before: between teeth, along the gumline. 而牙线可以进到牙刷不能到达的地方：牙间隙，牙龈边沿。
Because the edge of the crown extends to or below the gumline, it is critical to keep this area clean and healthy. 因为牙冠的外部一般都到达或在牙龈线下，很有必要保持这部分的清洁与健康。
