The outer porous layer is damaged after corrosion, while the inner dense layer played a key role to protect the coating from corrosion.

经一定的腐蚀时间后，微弧氧化陶瓷膜的多孔层最终遭到破坏，而紧密层对防腐蚀起着至关重要的作用。

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That's because hydrogen peroxide soaks through the protective outer coating of enamel and into the softer layer of dentin underneath, irritating the nerve-rich dental pulp at the core.

这是因为过氧化氢会渗入釉质的外部保护层并进入牙质下面的较为柔软的一层，刺激神经组织比较多的牙髓。

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The outer side face of the box body can attach an opaque decorative coating or a plated layer.

盒体的外侧面可带有不透光的装饰涂层或镀层。

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