A tooth is made up of several surfaces, somewhat like dice, that have several surfaces. The top of the tooth also has several small surfaces. Cavities can occur on more than one surface of the tooth and require separate drilling and filling. If there have been several cavities filled on different surfaces of one tooth you will see this in your bill. You will see for example a two-surfaced filling or three surfaced filling. (tweevlaks of drievlaks restauratie).