[Step-back method for intracanal preparation with multiple length determination of the tooth root canal]

A procedure of intracanal preparation of a cuneiform with cervical extension using a step-back technique is described. The length of the root canal is determined by multiple electric measurement. First, the initial measurement of the canal length (I1) is performed. The measured length is then transferred to the initial extender (No. 15), whereafter extirpation of the pulp and removal of circumpulpal dentin begin. Then the extender NO. 20 is reduced by 1 mm, and the extender No. 25 by 2 mm. When the canal have been narrowed and bent, further extenders are used to additionally reduce the working length by 1 mm more. When the pulp has been extirpated, the second canal length measurement (12) is performed, then starting to form the canal. In phase 1, the apical third from the initial (IAF) to the leading file (MAF) is treated and the cervical extension of the canal prepared by a bur drill. In further instrumentation, each next file is reduced by 1 mm of the measured canal length (12), thus shaping the canal by filling, using a step-back method. Files according to Hedström should be used thereby. Shaping of the canal is completed by a file by four numbers greater than the leading (MAF) one.