Three interworking items used to maintain artificial walls around a cavity prep are

Answer;

-Matrix

Explanation;

Matrix is used to maintain artificial wall around the tooth preparation.

Cavity preparation is the mechanical alteration of a tooth to receive a restorative material which will return the tooth and area to proper form, function and esthetics.

-Objectives of cavity Preparation: remove all defects and give the necessary protection to the pulp, locate the margins of the restoration as conservatively, form the cavity so that under the forces of mastication the tooth or the restoration will not be displaced and also Allow for the esthetic and functional placement of a restorative material.