A "filling" is a form of "direct" dental restoration used to repair a decayed, chipped, cracked or otherwise damaged tooth.
It is called a direct restoration because the material used to repair the tooth undergoes its hardening process while in "direct" contact with the tooth and *inside* the mouth. Other procedures such as inlays and onlays are considered to be "indirect" restorations because the material used to repair the tooth is created *outside the mouth*, either in a lab by a dental technician, or via a computer-controlled milling machine.
There are five surfaces of the tooth where a filling can be placed: the distal, occlusal, buccal, mesial and lingual/palatal surfaces. Additionally, teeth are segmented into two major categories: anterior, and posterior. Anterior, by definition, means "nearer the front," so the teeth in the front of your mouth - up to and including your incisors - are considered to be anterior. The remaining teeth fall under the category of posterior, which means, "further back in position, or nearer the rear."
With this dental procedure code, a "white" or "tooth-colored" filling made of composite resin is used to repair damage on two surfaces of a posterior, permanent tooth. (It’s worth noting this is an older code that existed at a time when there was a distinction in coding between permanent and primary tooth restorations of this nature.)
Such fillings are referred to as "tooth-colored" because of their unique ability to mirror the color, texture and luminescence of your own teeth. Aa resin filling bonds more securely with teeth than does a traditional amalgam filling, and can often be completed in a single visit.
To prepare for a single surface resin filling, a dentist will first remove any decayed or weakened areas of the tooth. Your tooth would then be prepared for bonding by etching it with a mild acid solution. After that, the composite filling would be layered into the areas of your tooth that need to be sealed. Finally, a special light is used to harden these layers and the tooth is shaped and polished to prevent staining and early wear.