Qualitative description of a new preparation technique: the balanced-force motion using the Endographe

The forces and torque applied during the balanced-force motion technique of root canal preparation were measured with the Endographe. Five endodontists prepared 100 extracted teeth, all straight and with similar root anatomy. The assignment of "tooth practitioner" was randomized. Gates-Glidden burs were used to prepare the coronal part and ensure apical patency for the other instruments. The balanced-force technique with conventional instruments was then used for the body of the canal. For the apical part either the watch-winding pull with conventional instruments or the reversed balanced-force technique with manual GT files was used. The Endogrammes were similar among endodontists for the coronal phase and showed low vertical forces in contrast with the lateral forces. For the body the Endogrammes were highly specific and described perfectly the different steps of instrument work. For the apical part the Endogrammes of the conventional instruments showed a lack of vertical forces. The Endogrammes of the manual GT files showed that torque was applied inversely to that of the conventional instruments. Force application was similar. In conclusion these objective data indicate the correct way of working with the different techniques incorporated into the balanced-force motion technique.