? 1. Endogenous blackening: This may be caused by some oral diseases, such as dental caries, tetracycline teeth and other common oral diseases. Because the bacteria contained in these diseases, through chemical reaction with food residues, then produce some acidic substances, and at the same time continue to corrode enamel, coupled with some pigments attached at ordinary times, make teeth constantly black and damaged, and gradually erode dentin and other tissues. So the teeth look black. 2. Exogenous blackening: This is mainly because patients may often eat some foods with high melanin, but food residues are left behind and not cleaned up in time. Therefore, it remains on the inside of the teeth for a long time, and even some melanin penetrates into the teeth through chemical reaction, resulting in signs of blackening inside the teeth. All the above situations need to go to a regular hospital as soon as possible in order to better prevent and treat dental problems. Shanghai Wanzhong Stomatological Hospital is a very professional stomatological hospital, adhering to the advanced oral service and business philosophy, and building the best stomatological hospital in Shanghai. After years of development, it has become a modern large-scale stomatological hospital with international standards, which integrates prevention, health care, treatment, beauty, plastic surgery and repair in Shanghai market. With exquisite medical technology, authoritative departments and professional medical team, it has formed a medical influence centered on Shanghai and radiating around.