Analysis of forces developed during obturations. Wedging effect: Part I.

The aim of this study was to define the "wedging effect" created by the intracanal forces developed during obturations and to measure it using a force analyzer device. In endodontics, the wedging effect is the result of, for example, a plugger pushing gutta-percha into a canal: the plugger functions much as the rod of a hydraulic jack and the vertical force applied by this rod induces in the cylinder (i.e. the canal) a hydrostatic pressure that is relatively equal in all directions. It is these forces resulting from the hydrostatic pressure that have been labeled the wedging effect. The original device, the Endographe, had a monobloc cupule for measuring the external vertical and horizontal forces developed by a practitioner, but it was unable to measure the intracanal forces. With a new cupule composed of two independent parts joined under pressure, the wedging effect was recorded and analyzed. Two obturation methods, warm vertical compaction and lateral condensation, were performed by endodontists. The forces were depicted by Endogrammes as a function of time. For all of the forces developed during the two techniques, the mean values showed a nonsignificant difference between the different practitioners. The use of graphs provides a new approach to the analysis of intracanal forces as they develop our time and permits the comparison of different obturation techniques.