After a tooth cavity is removed and cleaned the hole made is then filled with a dental material that restores the function and form so that it can stay healthy. This material can be gold, white composite, porcelain, or silver amalgam. The technique and cost depends on the material being used. A prescription strength fluoride toothpaste can be prescribed by the doctor when there is a high risk of cavities to help strengthen the tooth and prevent further decay in the future.
Dental joke: What do you call a dentist in the Army? A Drill Sergeant.