In a Class V preparation, what is the wall closest to the pulp known as?

In a Class V preparation, the wall closest to the pulp is referred to as the axial wall. This terminology is grounded in the anatomy of the tooth preparation, where the axial wall runs parallel to the long axis of the tooth and is positioned adjacent to the dental pulp. In this context, 'axial' aptly describes the orientation of the wall in relation to the tooth's structure, as it is on the side that faces inward toward the tooth's central structure.

To give further context to the other terms: the facial wall is oriented toward the cheek or lip, the lingual wall faces the tongue, and the gingival wall is at the bottom of the preparation, near the gumline. Each of these walls plays different roles in the preparation's design, but the axial wall is specifically the one adjacent to the pulp, making it crucial for understanding cavity preparation and protecting the pulp during restorative procedures.