I industry report _ obturation The DownPak Device: obturation with heat and vibration Authors_Dr Stephen Cohen, Dr Louis H. Berman & Dr Gabriela Martin, USA _Successful endodontic treatment depends on a proper diagnosis, a favourable prognosis assessment and proper cleaning, disinfection, shaping, and obturation of the canals and their associated radicular spaces. As countless studies have demonstrated that it may not be possible to disinfect and clean all canal ramifications thoroughly, obturation makes it possible to seal the roots internally to prevent leakage coronally or from peri-radicular tissues.1 Presently, there is no ideal obturation material. Gutta-percha remains the primary obturation material in use today, although other obturation filling materials have gained some recent attention, including Resilon (Pentron Clinical Technologies) and ProRoot MTA (DENTSPLY Tulsa Dental). All of these materials have some limitation in their ability to seal the main and accessory canals three-dimensionally. Nevertheless, it is important to obtain an homogenous mass of obturation material that will conform well to the interior walls of the canals when plasticised. Gutta-percha and Resilon are the most suitable materials. Heated gutta-percha changes its crystalline form from a beta phase, which is relatively solid, to an alpha phase, in which it becomes a more plasticised and sticky material that adheres better to the canal walls.2 In its alpha phase, guttapercha can be compacted vertically and laterally, by mechanical or rotary instruments. Resilon, a polyester- and methacrylate-based resin obturation material, has good flow when warmed. One study concludes that Resilon bonds to etched canal walls when heated, which may provide a tighter seal of the canal system while also strengthening the root system.3 Several techniques have been used to facilitate the placement of gutta-percha, including cold and warm lateral compaction, warm vertical compaction, injectable systems, carrier-based obturation and thermomechanical compaction. All of these techniques require various degrees of clinical proficiency and, depending on the canal system that is to be obturated, certain techniques may be more appropriate than others. For example, when a tooth has a large internal resorption defect in the canal, cold lateral compaction may not adequately fill all of the canal space, whereas vertically compacting or injecting warm gutta-percha may provide a more 3-D obturation. Considering the multitude of canal ramifications in any given tooth, it may be impossible to fill these spaces three-dimensionally unless the gutta-percha is heated. In vitro studies have demonstrated that cold lateral compaction of gutta-percha is approximately 25 per cent less dense than warm lateral compaction; additionally, it has been shown that gutta-percha fills significantly more canal space when warm vertical compaction is used.4–6 Even after heating and compacting gutta-percha or Resilon into a canal system, there still may be voids in the obturation. To min- Fig. 1_The DownPak is a self-contained device that transfers heat and vibration to a spreader or plugger tip. All of the controls are easily accessible on the handle. Fig. 1 38 I roots 4_ 2009