In most cases, teeth undergoing endodontic treatment suffer extensive coronal destruction. In order to guarantee the success of our treatment, we must avoid both bacterial contamination of the oral environment and the exit of the irrigants or instruments that we are going to use into the patient’s mouth. Prior reconstruction of the area can be a very simple and quick procedure, provided the appropriate techniques and materials are known. Similarly, the placement of an absolute isolation, which offers a wide working field and allows for an aseptic environment, is a simple task once the clinician acquires the necessary skills. The aim of this paper is to describe the materials required and to outline the various current techniques.  A series of case studies will allow all the knowledge acquired to be applied directly to daily clinical work.