When the enamel of the tooth becomes too weak, small holes will start to develop in the actual tooth. If this is the case, your dentist will need to fix the problem, most likely with a filling, or else it will become worse.
Fillings are placed when dentists remove all the damaged tooth and other material from the small hole and then fill the hole with a substance to block any future damage to that part of the tooth. Fillings are made with resins or a combination of materials to protect the tooth.