It is caused by poor dental hygiene . a layer of plaque accumulates along the gum margin 牙周病的形成，一般是由于牙不清洁，导致牙垢膜积聚在牙表面。
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It is caused by poor dental hygiene . a layer of plaque accumulates along the gum margin 牙周病的形成，一般是由于牙齿不清洁，导致牙垢膜积聚在牙齿表面。
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A new study suggests that gum disease may result from reduced levels of a key enzyme in cells in addition to indifferent dental hygiene 一项新的研究提示，牙龈疾病除了口腔卫生不良以外，还可能由于细胞内一种重要酶的水平降低而发生。
