DTUK1910

July 19-25, 201012 Endo Tribune United Kingdom Edition T he goals of canal preparation are: • To leave the minor con- striction (MC) of the apical foramen in its original position • To leave the MC at its original size • To leave the canal in its initial position and only enlarge it as de- scribed here • To optimise the taper of the pre- pared canal for ideal irrigation and obturation hydraulics • To prepare a tapering funnel from orifice to apex with narrowing cross sectional diameters • To prepare a taper that achieves the above objectives without risk of per- foration and long-term vertical root fracture While a comprehensive descrip- tion of previous systems used to achieve these objectives is beyond the scope of this article, one new meth- od is described here - the Twisted File (TF) (SybronEndo, Orange, CA, USA). TF allows these objectives to be achieved with the least number of instruments and fewest insertions of any rotary nickel titanium (RNT) system currently available. Evidence exists in the scientific endodontic lit- erature that TF provides the greatest flexibility, fracture resistance and cutting ability of any commercially available system. Clinical Considerations in the Use of the Twisted File • TF is inserted passively to resist- ance. The file should always be either inserted or withdrawn but never held stationary in the canal • TF, as with all RNT files, should be used with copious irrigation • Irrigation and recapitulation should follow every insertion • The flutes of TF should be wiped clean after every insertion • TF insertion should be a smooth and continuous single insertion that lasts two-three seconds followed by withdrawal. The file is not pumped up and down into the canal • TF can be rotated at 500-900 RPM and can be used with any electric motor desired with or without torque control Clinical Use of the Twisted File As mentioned above, TF requires fewer files, fewer insertions and al- lows the preparation of larger tapers and master apical diameters than many other systems. It does so safely and predictably as described with the following steps: • An estimate of the true working length is made before starting the treatment. This is known as the esti- mated working length (EWL) • Access is a straight line and all ca- nals are located before commencing orifice shaping • The cervical dentinal triangle is removed using the .08/25 TF with a brushing motion up and away from the furcation. The intention is to re- move the cervical dentinal triangle, define the orifice, and provide effi- cient tactile control over the subse- quent insertion of hand K files (HKF) into the root • Using TF, after orifice shaping, the clinician should achieve apical pat- ency with a small HKF (usually a #6 or #8 HKF). A #6 HKF is often the first file to routinely achieve or verify api- cal patency. This #6 HKF is optimally precurved with the EndoBender* pli- ers, a modified orthodontic pliers, which delivers the desired curvature to the HKF. Curved canals are more effectively negotiated using curved HKFs. HKFs used for achievement of patency are inserted gently and pas- sively with an intention to find the ca- nal path. At this stage in the process, HKFs are used only to obtain patency and not to shape the canal. In a com- plex three-dimensional curvature and/or calcified canal it may take a number of insertions at different an- gles to obtain patency, especially if a blockage is present. Flexibility is our Strength Using a New and Inno- vative Technology for Routine Endodontics: The Twisted File Richard Mounce looks at the use of twisted files in treatment for patients Fig 1: Clinical cases treated with Twisted Files* in the manner described in the article using RealSeal* master cones via the Elements Obturation Unit* and SystemB technique. Fig 2: Clinical cases treated with Twisted Files* in the manner described in the article using RealSeal One Bonded Obturators.*