I don't know if I'm talking about two upper incisors, that is, between the teeth, which are dark and stick to them like eating, and sometimes it's embarrassing to talk, because I've had them before. It's tooth decay. If you look closely, you can see that there is a small hole on the edge of both teeth. If I say so, you must see a dentist. Because the tooth decay will get bigger and bigger, the cavity will spread with the tooth decay, and the teeth will get darker and darker until the two teeth are completely black, which may lead to tooth decay. Therefore, it is necessary to fill the teeth as soon as possible. If the black range is large, it is recommended to make porcelain teeth, because the filling time is not long, it will fall off, it will be more ugly, wasting time and money. It's for the best.