Drs. Julian Webber, Pierre Machtou, Wilhelm Pertot, Sergio Kuttler, and John West examine the WaveOne™ system
The new WaveOne™ NiTi file from Dentsply Tulsa Dental Specialties is a single-use, single-file system designed to shape the root canal completely from start to finish. Shaping the root canal to a continuously tapering funnel shape not only fulfills the biological requirements for adequate irrigation to clean the root canal system of all bacteria, bacterial by-products, and pulp tissue (Sjogren et al, 1997), but also provides the perfect shape for three-dimensional obturation with gutta percha (Schilder, 1974; West JD, 2008).
In most cases, the technique requires only one hand file followed by one single WaveOne™ file to shape the canal completely. The specially designed NiTi files work in a similar but reverse “balanced force” action (Roane, Sabala, Duncanson, 1985) using a pre-programmed motor to move the files in a back-and-forth “reciprocal action.” The files are manufactured with M-Wire® technology, improving strength and resistance to cyclic fatigue by up to nearly four times in comparison with other brands of rotary NiTi files (Johnson et al, 2008). There are many dentists who are reluctant to use NiTi rotary instruments to prepare canals, despite the recognized advantages of flexibility, less debris extrusion, and maintaining canal shape, among other advantages (Walia, Brantley, Gerstein, 1998; Reddy, Hicks, 1998; Pettiette, Delano, Trope, 2001). For them, the use of a single reciprocating file would be very attractive both in terms of time and cost saving.
At present, there are three files in the WaveOne™ single-file reciprocating system available in 21-mm, 25-mm, and 31-mm lengths (Figure 1):1. The WaveOne™ Small file is used in fine canals. The tip size is ISO 21 with a continuous taper of 6%2. The WaveOne™ Primary file is used in the majority of canals. The tip size is ISO 25 with an apical taper of 8% that reduces towards the coronal end3. The WaveOne™ Large file is used in large canals. The tip size is ISO 40 with an apical taper of 8% that reduces toward the coronal end.
The instruments are designed to work with a reverse cutting action. All instruments have a modified convex triangular cross section at the tip end (Figure 2) and a convex triangular cross section at the coronal end (Figure 3). This design improves instrument flexibility overall. The tips are modified to follow canal curvature accurately. The variable pitch flutes along the length of the instrument considerably improve safety (Figure 4).
Because there is a possibility of cross-contamination associated with the inability to completely clean and sterilize endodontic instruments (Letters et al, 2005) and the possible presence of prion in human dental pulp tissue (Schneider et al, 2007), all instruments used inside root canals should be single use (Department of Health [UK], 2007). WaveOne™ instruments are a new concept in this important standard of care, as they are truly single use. The plastic color-coding in the handle deforms if sterilized, 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 an even more important consideration with WaveOne™ files, as one file does the work traditionally performed by three or more rotary NiTi files.
The e3™ Torque Control Motor (Dentsply Tulsa, Figure 5) is rechargeable battery-operated with a 6:1 reducing handpiece. The pre-programmed motor is preset for the angles of reciprocation and speed for WaveOne™ instruments. The counter-clockwise (CCW) movement is greater than the clockwise (CW) movement. CCW movement advances the instrument, engaging and cutting the dentin. CW movement disengages the instrument from the dentin before it can (taper) lock into the canal. 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 e3™ 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 e3™ motor with its reverse reciprocating function.
The WaveOne™ technique involves the following stages:1. Straightline access, accepted protocol2. WaveOne™ file selection3. Single-file shaping 4. Copious irrigation with 5% NaOCl and EDTA before, during and after single-file shaping.WaveOneTM file selection and clinical procedure (Figures 6, 7, 8)While a good preoperative periapical radiograph will give an indication of what to expect before the canal is prepared (size and length of canal, number of canals, degree and severity of curvature), only the first hand file into the canal will aid in the selection of the WaveOne™ file as follows:1. If a 10 K-file is very resistant to movement, use the WaveOne™ Small file2. If a 10 K-file moves to length easily, or is loose or very loose, use the WaveOne™ Primary file3. If a size 20 hand file or larger goes to length, use the WaveOne™ Large file. Single file shaping1. Take the hand file into the canal and watch-wind to length or resistance (approximately two-thirds of canal length)2. Use the appropriate WaveOne™ file to approximately two-thirds of canal length3. Irrigate copiously4. Take the hand file to length and confirm with an apex locator and radiograph5. Take the WaveOne™ to length6. Confirm the foramen diameter with a hand file the same size as the WaveOne™ file. If snug, preparation is complete7. If the foramen diameter is larger than WaveOne™ file, consider the next larger WaveOne™ file8. The majority of cases will be completed with the WaveOne™ Primary file.Guidelines for use1. Use WaveOne™ files with a progressive up-and-down movement no more than three to four times; only little force is required2. Remove the file regularly, wipe clean, irrigate, and continue3. If the file does not progress, confirm patent canal and consider using a smaller WaveOne™ file4. While glide path management is minimal with WaveOne™ shaping files, some practitioners will be more comfortable if the glide path is first secured with PathFiles™ (Dentsply Tulsa Dental Specialties)5. In severely curved canals, complete apical preparation by hand if a reproducible glide path is not possible6. WaveOne™ files can be used to relocate the canal orifice and expand coronal shape; even in a reciprocating motion, use them with a “brushing” action short of length to achieve this7. Never work in a dry canal, and constantly irrigate with NaOCl and later EDTA8. As preparation time is short, activate the irrigating solutions to enhance their effect; the EndoActivator® (Dentsply Tulsa Dental Specialties) is ideal for this (Figure 9) (Ruddle, 2008).WaveOne™ obturating solutionsObturation of the root canal system is the final step of the endodontic procedure. The WaveOne™ system includes matching paper points, gutta-percha points, and obturators (Figures 10-12). The matching gutta-percha points can be used in conjunction with the Dentsply Tulsa Dental Specialties Calamus® Dual 3D Obturation System as demonstrated in the following cases. Case I (Figures 13A-13C)Tooth No. 36 presented with symptoms of irreversible pulpitis and early apical periodontitis. Initial radiographic assessment showed four narrow and curved canals. Access was made, and all canals were worked to length with a 10 K-file. A WaveOne™ Primary file (25 .08) was selected, and length was reconfirmed with a 10 K-file. The WaveOne™ Primary file was worked to length in all four canals. Obturation was done with warm vertical condensation (WVC) using Calamus® Dual.Case II (Figures 14A-14C)Tooth No. 16 had symptoms of acute pulpitis with a temporary filling, covering exposure distally, as well as severe curvature of the mesiobuccal (MB) canals and apically in the distal canal. K-files 8 and 10 were taken to length in all the canals. A WaveOne™ Primary file (25.08) was selected. Length was confirmed with a 10 K-file. The WaveOne™ Primary file was taken to length in all the canals. Obturation was done with WVC using Calamus® Dual.
Case III (Figures 15A-15C)Tooth No. 17 presented with radiographic evidence of apical periodontitis and was nonvital. The canals were hardly visible on the preoperative x-ray. Primary consideration would have been a WaveOneTM Small file (21.06). In all canals, the 8 K-file moved to length easily. The 10 K-file also moved to length, but was tight. A WaveOne™ Primary file (25.08) was selected and taken to approximately three-quarters of the length. Recapitulation was achieved with a 10 K-file to length. The WaveOne™ Primary file was taken to length in all the canals, and the canals were then obturated with WVC.Case IV (Figures 16A-16C)Tooth No. 16 presented with radiographic evidence of asymptomatic apical periodontitis. The canals were hardly visible on the preoperative x-ray. The MB canal was severely curved, and the distobuccal (DB) and palatal were not visible. A 10 K-file moved to length easily in the MB and DB canals. In the palatal canal, 10 and 15 K-files moved to length easily. A WaveOne™ Primary file (25.08) was selected for all canals. Lengths were confirmed, and the canals were shaped to length with WaveOne™ files.
In tooth No. 15, a large, single canal was clearly visible. Size 20 and 25 K-files went to length and a WaveOne™ Large file (40:08) was selected. Canal length was confirmed, and the WaveOne™ Large file was used to shape the canal.Advantages of the WaveOne™ file reciprocating system1. Only one NiTi instrument is used per root canal and in most cases per tooth2. Lower cost3. Less instrument separation due to the unique reciprocating movement that will prevent and/or delay the instrument from advancing from plastic deformation to its plastic limit4. Decreases global shaping time, allowing the clinician to spend more time cleaning the root canal system with enhanced irrigation techniques5. Eliminates procedural errors by using a single instrument rather than using multiple files6. A new standard of care, eliminating the possibility of prion contamination owing to single use7. Easy to learn8. Easy to teach.WaveOne™ researchThe Nova Southeastern University College of Dental Medicine in Ft. Lauderdale-Davie, Florida, is conducting research into WaveOne™. The following areas of research, among others, are being investigated using micro-focus CT scanning technology, which provides remarkable insight into:1. Canal centering ability of WaveOne™ (Kuttler et al, 2011) (Figures 17A-17C)2. Remaining canal wall thickness after instrumentation with WaveOne™ (Webber et al, 2011)3. Final shape versus initial shape of the canal with WaveOne™ (Pertot et al, 2011)4. Canal wall cleanliness with WaveOne™ (Machtou et al, 2011) (Figures 18A-18C).
Other areas of research are flexibility (Mclean et al, 2011), fatigue (Coil et al, 2011), and debris extrusion (Armando et al, 2011). To date, the results of these studies suggest that WaveOne™ single reciprocating files are comparable in performance to all the major leading brands of NiTi files that operate in continuous rotation.
ConclusionThe WaveOne™ system is an exciting new concept in the preparation of the root canal. While current teaching advocates the use of multiple NiTi files of different diameters and tapers to gradually enlarge the root canal, only one WaveOne™ single shaping file is required to prepare the canal to an adequate size and taper, even in narrow and curved canals.
However, along with this, there must be a caveat. WaveOne™ files only shape the canal, extremely quickly in many instances, but they do not clean the root canal. It is the duty of teachers, clinicians, and manufacturers to emphasize the role and importance of irrigation as a major determinant of endodontic success. Once it is fully appreciated that shaping and cleaning the root canal system are irrevocably intertwined, then endodontics will be easier for all and available to all, and WaveOne™ will truly become the root canal preparation instrument of the future.
AcknowledgementThis article originally appeared in roots_international magazine of endodontology 7(1):2011. It is adapted and reprinted with permission from Oemus Media AG. © 2011 Oemus Media AG. Drs. Julian Webber, Pierre Machtou, Wilhem Pertot, Sergio Kuttler, Clifford Ruddle, and John West were involved in the development, field testing, and research associated with WaveOne™. Figures 19A-21C have been added to this Endodontic Practice US version from recent cases. Figures 19A-C have been added courtesy of Dr. Sergio Kuttler, and Figures 20A-21C have been added courtesy of Dr. Rigoberto Perez, Acapulco, Mexico. Dr. Perez has completed more than 300 endodontic cases with the WaveOne™ Single File Reciprocating NiTi System.
Dr. Julian Webber has been a practicing endodontist in London for more than 30 years. He was the first UK dentist to receive a Master’s degree in endodontics from a university in the United States (Northwestern University Dental School, Chicago) in 1978. He has lectured extensively and given many hands-on courses on endodontics worldwide. He is a fellow of the International College of Dentists and an active member of the American Association of Endodontists. Dr. Webber is the editor-in-chief of Endodontic Practice (UK).Dr. Pierre Machtou graduated in 1967 at the Paris 7-Denis Diderot University. He completed his habilitation and became a professor at the same university in 1997. He is the past scientific director and general secretary of the French Endodontic Society. He is a member of numerous national and international endodontic and dental societies, such as AAE, ESE, Pierre Fauchard Academy, and is a Fellow of the International College of Dentists. In 2006, he was the recipient of the Pierre Fauchard Elmer S. Best Memorial Award. He serves as an associate editor of Endodontic Practice (UK). He has limited his practice to endodontics since 1978.Wilhelm Pertot, DCD, DEA, PhD, graduated in 1988. He earned a Master in Endodontics from Marseille Dental School and obtained a PhD thesis in 1996. He was nominated assistant professor in 1991, promoted to lecturer in 1994, and served as co-director for the postgraduate program in endodontics in Marseille Dental School from 1992 to 2000.
Sergio Kuttler, DDS, BS, received his dental degree in 1978 from the Universidad Tecnologica De Mexico, Mexico City, Mexico. In 1984, Dr. Kuttler received his endodontic certificate from the University of Southern California. He has been involved in academics since his graduation from USC, and practicing exclusively endodontics. Dr. Kuttler is presently professor of the department of endodontics and associate dean for advanced education programs at Nova Southeastern University, College Of Dental Medicine in Fort Lauderdale, Florida. He also practices endodontics exclusively in the faculty practice at the university. As the founder and director of the Center for Endodontics, John West, DDS, continues to be recognized as one of the premier educators in clinical and interdisciplinary endodontics. Dr. West received his DDS from the University of Washington in 1971 where he is an affiliate associate professor. He then received his MSD in endodontics at Boston University Henry M. Goldman School of Dental Medicine in 1975, where he is a clinical instructor and has been awarded the Distinguished Alumni Award. Dr. West has presented more than 400 days of continuing education in North America, South America, and Europe, while maintaining a private practice in Tacoma, Washington.
ReferencesArmando L, Kuttler S, Bonilla C, et al (2011) Comparison of the extruded debris of a new nickel titanium reciprocating file versus four conventional rotary systems. In press.Coil J, Shen Y, Kuttler S, et al (2011) Incidence of instrument failure of a new nickel titanium reciprocating file system: a clinical evaluation in a postgraduate endodontic program and private practice. In press.Department of Health (UK) (2007) Advice for dentists on the re-use of endodontic instruments and variant Creutzfeldt-Jacob Disease (vCJD) Johnson E, Lloyd A, Kuttler S, et al (2008) Comparison between a novel nickel titanium alloy and 508 Nitinol on the cyclic fatigue life of ProFile 25/.04 rotary instruments. J Endod 34(11):1406-1409.Letters S, Smith AJ, McHugh S, et al (2005) A study of visual and blood contamination on reprocessed endodontic files from general dental practice. Brit Dent J 199:522-525.Kuttler S, Bonilla C, Perez R, et al (2011) Evaluation of remaining canal wall thickness and center ability after instrumentation with a new reciprocating system. In press.Machtou P, Kuttler S, Bonilla C, et al (2011) Evaluation of canal wall cleanliness after instrumentation with four nickel titanium rotary file systems and one reciprocating system. In press.Mclean R, Kuttler S, et al (2011) Evaluation of the flexibility of four nickel titanium rotary file systems and one reciprocating file system. In press.Pertot W, Machtou M, Kuttler S, et al (2011) Evaluation of remaining canal wall thickness and center ability after instrumentation with WaveOne reciprocating system vs Revo-S rotary NiTi system. In press.Pettiette MT, Delano EO, Trope M (2001) Evaluation of success rate of endodontic treatment performed by students with stainless steel K-files and nickel titanium hand files. J Endod 27(2):124-127.Reddy SA, Hicks ML (1998) Apical extrusion of debris using two hand and two rotary instrumentation techniques. J Endod 24:180-183.Roane JB, Sabala CL, Duncanson MG (1985) The ‘balanced force’ concept for instrumentation of curved canals. J Endod 11(5):203-211.Ruddle CJ (2008) Endodontic disinfection: tsunami irrigtion. Endo Prac 11:7-16.Schilder H (1974) Cleaning and shaping the root canal. Dent Clin Amer 18(2):269-296. Schneider K, Korkmaz Y, Addicks K, et al (2007) Prion Protein (PrP) in human teeth: an unprecedented pointer to PrP’s function. J Endod 33(2):110-113.Sjogren U, Figdor D, Persson S, et al (1997) Influence of infection at the time of root filling on the outcome of endodontic treatment of teeth with apical periodontitis. Int Endod J 30(5):297-306. Walia HM, Brantley WA, Gerstein H (1998) An initial investigation on the bending and torsional properties of Nitinol root canal files. J Endod 14(7):340-351. Webber J, Kuttler S, Bonilla C, et al (2011a) Evaluation of remaining canal wall thickness and center ability after instrumentation with WaveOne reciprocating system vs rotary BioRace NiTi system. In press.West JD (2008) Endodontic predictability–restore or remove: how do I choose? In: Cohen M, ed. Interdisciplinary Treatment Planning: Principles, Design, Implementation. Quintessence Publishing Co, Chicago:123-164.
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