The bravery insideenamel: the enamel of bravery surface is metalloid material inside, both neither is rusty, also do not have furring, have stronger compression capacity.
搪瓷内胆：内胆表面的瓷釉为非金属材料，既不生锈，也无水垢，有较强的耐压能力。
2
A white spot appears on the enamel where the tooth has started to weaken inside.