A standard predetermined endodontic preparation concept

Cleaning and shaping the root canal system is the most tedious and demanding phase of endodontic therapy. Using a predetermined endodontic preparation allows for a routine approach to instrumentation and produces high-quality results with better efficiency. Schilder states, "Inherent in the concept of cleaning and shaping is the fact that each root canal system, like each carious lesion, is different from another and that, within certain prescribed guidelines no two root canal preparations should be exactly alike, anymore than any two intracoronal preparations are exactly alike." The concept of predetermined preparation does not conflict with Schilder's statement, it merely refines prescribed instrumentation guidelines and establishes instrumenting parameters. The goals of endodontic instrumentation are to: (1) instrument with control so that there is enlargement without deviation from the original canal; (2) instrument to a size that is consistent with total mechanical and chemical debridement; (3) debride the root canal system from its coronal orifice to the periodontal ligament, regardless of canal curvature; and (4) create a canal shape that tapers from the coronal orifice to the apical opening. The authors will discuss each endodontic goal as it is accomplished in the predetermined preparation. Techniques for instrumenting to the predetermined sizes are also described.