Does not tooth decay occur after filling?

The only treatment method after caries occurs is to remove dirt, that is, to remove decay and then fill it. After filling teeth may also occur caries. Why? First, our filling material and teeth are not absolutely seamless, not seamless connection, it has extremely small gaps, when conditions permit, but also along the original filling and teeth between caries. Second, where there is no filling, caries will continue to occur. Therefore, our filled teeth are not foolproof, and there may continue to occur caries, should cause enough attention to patients, do not ignore these treated teeth, do not let him re-attack.