Tooth decay is commonly known as “worm teeth”. Parents often tell their children: if you don’t brush your teeth, the bugs will eat your little teeth! In fact, tooth decay is not caused by worms, but an infectious disease of the hard tissue of teeth, which is also caused by bacteria. But it doesn’t mean that there will be caries if there are bacteria, the final formation of caries depends on four factors, which we call the four elements of caries: bacteria, host (that is, its own cause), food and time. When all four conditions are satisfied, caries can be formed. If the brushing method is incorrect or incomplete, it cannot be called effective brushing, which will make more plaque remain on the tooth surface and cannot play the role of caries prevention. Effective brushing can remove plaque to the maximum, but brushing can not remove all plaque, brushing plus using toothpicks, dental floss and other auxiliary cleaning supplies, can only clean 70%~80% of the tooth surface area, the remaining 20%~30% of the place is still a dead corner, it is easy to become a hotbed of oral disease, the dead corner parts such as the adjacent surface of the teeth, the teeth in the back position are more likely to appear caries. There are some friends who have done a good job of self oral hygiene care, but because there are some deep grooves in the teeth structure itself, it is impossible to clean them, and these parts are also easy to appear caries. Therefore, we suggest you to go to the hospital for oral examination once every six months or so, and our doctor can also guide you how to brush your teeth according to your situation.