A new endodontic instrumentation system, Protaper Next from Dentsply, has been developed to make mechanical tapering of the root canal system more efficient. Decreasing preparation time maximizes the potential for thorough irrigation of the root canal system with sodium hypochlorite, a prerequisite for successful endodontic treatment. The instruments are manufactured in NiTi M-wire, have a rectangular cross section and rotate with ‘swagger’; this eccentric motion delivers less torque and greater flexibility whilst cutting and allows greater debris removal.
A 13 year old girl was referred for root canal treatment of her mandibular right first molar (46). The tooth had become necrotic following gross caries. The curved and delicate roots had fine root canals visible on the radiograph, and there was a radiolucent area present in the furcation region (fig 1).
Under good local anaesthesia, a rubber dam was applied and, following caries removal, the canal orifices exposed. The ProTaper Next instruments are available in sizes X1 to X5, and, in most cases, you only need to use X1 and X2 to complete preparation. They are rotated at 300rpm in an electric motor with a torque control of 2Ncm.
The canals were prepared according to the manufacturer’s protocol:
? Preparation of straight-line access.
? Explore the canal using small-sized hand files, determine working length,
verify patency and confirm a smooth,reproducible glide path.
? In the presence of NaOCl, brush and follow, along the glide path, with the ProTaper Next X1 (017/04) file, in one or more passes, alternating with smallsized hand files if necessary, until the working length is reached.
? Use ProTaper Next X2 (025/06), exactly as described for ProTaper Next X1 file, until the working length is passively reached.
? Inspect the apical flutes of the ProTaper Next X2 file; if they are loaded with dentine, then the shaping is finished. The correspondingly sized gutta percha master cone or size verifier may be fitted, and the canal is ready for disinfection.
A brushing technique is invaluable as it creates space for the instrument to advance along the canal. The pulp chamber is always flooded with sodium
hypochlorite and debris carted in the flutes is dispersed into it on the outstroke.
In this case the X2 instrument had debris in the flutes of the tip when taken to the working length and therefore preparation was complete at this point
in all canals.
A three per cent sodium hypochlorite solution was used throughout preparation and during the irrigation phase. Passive sonic irrigation in 20 second bursts was used to agitate the solution and smear layer removal carried out with 20 per cent citric acid.
Finally, when thorough disinfection was complete, the case was obturated
with Gutta-Core combined with AH Plus sealer and the access completely sealed with a composite core. The final radiograph shows a clear lateral canal in the vicinity of the lateral furcal radiolucency. The case was reviewed at six months to assess bony healing (fig 2).
ProTaper Next proved extremely easy to use. The total mechanical preparation time for this particular molar from the point of confirming working length to completion of tapering was approximately six minutes. Excessive tapering could have resulted in a strip perforation, making ProTaper Next a good option for this case.
The ProTaper Next system is easy to use, with pre-programmed torque and speed control on the dedicated X-Smart Plus motor. The files are extremely flexible which can be helpful in cases with limited access and in highly curved canals. With most rotary instruments working through a pool of sodium hypochlorite is imperative, it helps to wash away debris being carried in the flutes of the instruments and thereby prevents locking of the instrument in the root canal. In cases with very thin roots, for example premolars with S-shaped configurations and bi-concave cross-sectional shape, strip perforation is a risk if an instrument with too great a taper is used. ProTaper Next instruments will respect the original canal morphology and glide path and have a variable taper meaning taper gradually increases as you move up the file system, helping to manage the more complex cases.