RO0111

I 29 clinical technique _ WaveOne I roots1_2011 (Fig. 2) and a convex triangular cross-section at the coronal end (Fig. 3). This design improves instrument flexibilityoverall.Thetipsaremodifiedtofollowcanal curvature accurately. The variable pitch flutes along the length of the instrument considerably improve safety (Fig. 4). Because there is a possibility of cross-contamina- tion associated with the inability to completely clean and sterilise endodontic instruments9 and the possi- blepresenceofprioninhumandentalpulptissue,10 all instruments used inside root canals should be single use.11 WaveOneinstrumentsareanewconceptinthis important standard of care, as they are truly single use. The plastic colour coding in the handle becomes deformed once sterilised, preventing the file from being placed back into the handpiece. The recommendation for single use has the added advantage of reducing instrument fatigue, which is anevenmoreimportantconsiderationwithWaveOne files,asonefiledoestheworktraditionallyperformed by three or more rotary NiTi files. TheWaveOnemotor(Fig.5)isrechargeablebattery operatedwitha6:1reducinghandpiece.Thepre-pro- grammed motor is set for the angles of reciprocation and speed for WaveOne instruments. The counter- clockwise(CCW)movementisgreaterthantheclock- wise (CW) movement. CCW movement advances the instrument, engaging and cutting the dentine. CW movement disengages the instrument from the dentinebeforeitcan(taper)lockintothecanal.Three reciprocating cycles complete one complete reverse rotation and the instrument gradually advances into the canal with little apical pressure required. All brands of NiTi files can be used with the WaveOne motor, as it has additional functions for continuous rotation. However, as WaveOne files have their own unique reverse design, they can ONLY be used with the WaveOne motor with its reverse reciprocating function. The WaveOne technique involves the following stages: 1. straightline access, accepted protocol; 2. WaveOne file selection; 3. single-file shaping; 4. copious irrigation with 5% NaOCl and EDTA before, during and after single-file shaping. _WaveOne file selection and clinical procedure (Figs. 6–8) Whilst a good preoperative periapical radiograph will give an indication of what to expect before the canal is prepared (size and length of the canal, number of canals, degree and severity of curvature), Fig. 4_WaveOne variable pitch flute increases safety. Fig. 5_WaveOne motor and 6:1 reducing handpiece. Figs. 6–8_WaveOne Small, Primary and Large files with their respective file selection and clinical procedural flow chart. Fig. 6 Fig. 7 Fig. 8 Fig. 4 Fig. 5