Dental fillings are required because of the deterioration of the tooth due to holes caused by tooth decay. Left unchecked, the decay will continue to spread and damage the tooth. During the filling procedure dentists clean away the decay inside the cavity, usually with a drill to prevent further damage. But this doesn’t fix the damage that has already been created, so a filling is necessary. The intent of the filling is to replace the part of the tooth that is missing or destroyed by tooth decay. The dentist molds the filling to match the shape of the surrounding tooth, which restores the strength and integrity of the tooth and prevents further decay from happening.