1. A hole in a tooth produced in response to caries or non-biological tooth loss such as abrasion or trauma.
2. A hole in a tooth prepared by mechanical instrumentation prior to the insertion of a restorative material. An approximal cavity is located on the mesial or distal surface of a tooth. A compound or complex cavity involves more than one tooth surface. The internal walls and margins of a cavity are defined according to their location. See also Black's classification of cavities.
The walls of a mesio-occlusal cavity in a lower left first molar