The tooth is placed through a hole in the dam, and the dam is held in place by a clamp attached to the tooth. This keeps the tooth dry and isolated. In addition, the rubber dam prevents files and irrigants from going down the patient's throat. Once the canals are located, files are used to clean the canals. Files can either be used with hands only or with a handpiece.
Endodontic files come in various lengths and diameters.
Different files are necessary for the many different lengths of canals. Various diameters are needed to properly shape the canal. When the canal is being cleaned, it is also being shaped. Canals need to be conically shaped to be properly filled. Electronic apex finders can help locate the apex.