Aim: Complex anatomy of roots requires endodontic rotary instruments that respect and follow that anatomy. The purpose of this study was to compare the shaping ability of three engine-driven nickel-titanium instruments in severely curved simulated canals.
Materials and methods: Forty-eight severely curved simulated canals in resin blocks were prepared to an apical size of 25 using the following systems (n = 16 per group): ProTaper Universal (PTU), ProTaper NEXT (PTN), and WaveOne Primary (WO) (all Dentsply Maillefer, Ballaigues, Switzerland). Composite images were made from the superimposition of pre- and post-instrumentation images. The amount of resin removed by each system was measured by using a digital template and image analysis software. Shaping ability of each system was compared using different parameters: total resin removal, centering ability, canal transportation in the apical, middle and coronal third of canal. Preparation times were also recorded. The data were statistically analyzed by using analysis of variance, paired t-test, and Tukey's post hoc test.
Results: Canals prepared with PTN were better centered in the apical part than those prepared with WO and PTU (p < 0.05). WO removed significantly more resin at the outer aspect of the maximum point of curvature. WO and PTU caused similar canal transportations at 7 points out of 11 measuring points. At measuring points 3, 4, and 5 WO caused more canal straightening than PTU. Instrumentation with PTU required more time than with the two other instruments (p <0.05). No preparation error or instrument separation occurred.
Conclusion: In the apical part of the canals PTN obtained the best results with regard to canal transportation.
Clinical Significance: All of the rotary instruments were safe in preparing severely curved canals and PTN showed better preparation of apical part of the canal.
Schilder H. Cleaning and shaping the root canal. Dent Clin North Am. 1974 Apr;18:269-296.
Sanfelice CM, da Costa FB, Reis Só MV, et al. Effects of Four Instruments on Coronal Pre-enlargement by Using Cone Beam Computed Tomography. J Endod. 2010 May;36: 858-861.
Schäfer E, Florek H. Efficiency of rotary nickel-titanium K3 instruments compared with stainless steel hand K-Flexofile. Part 1. Shaping ability in simulated curved canals. Int Endod J. 2003 Mar;36:199-207.
Baugh D, Wallace J. The role of apical instrumentation in root canal treatment: a review of the literature. J Endod. 2005 May;31:333-340.
Peters OA. Current challenges and concepts in the preparation of root canal systems: a review. J Endod. 2004 Aug;30: 559-567.
Yared G. Canal preparation using only one Ni-Ti rotary instrument: preliminary observations. Int Endod J. 2008 Apr;41:339-344.
Bürklein S, Hinschitza K, Dammaschke T, et al. Shaping ability and cleaning effectiveness of two single-file systems in severely curved root canals of extracted teeth: Reciproc and WaveOne versus Mtwo and ProTaper. Int Endod J. 2012 May;45:449-461.
Varela-Patino P, Ibanez-Parraga A, Rivas-Mundina B, et al. Alternating versus continuous rotation: a comparative study of the effect on instrument life. J Endod. 2010 Jan;36:157-159.
Pereira ES, Viana AC, Buono VT, et al. Behavior of nickeltitanium instruments manufactured with different thermal treatments. J Endod. 2015 Jan;41:67-71.
Bürklein S, Mathey D, Schäfer E. Shaping ability of ProTaper NEXT and BT-RaCe nickel-titanium instruments in severely curved root canals. Int Endod J. 2015 Aug;48:774-781.
Maia Filho EM, Dos Reis Santos RM, Lima DM, et al. Shaping Ability of ProTaper Next, WaveOne, and Reciproc in Simulated Root Canals. J Contemp Dent Pract. 2016 Nov;17(11):902- 906.
Troiano G, Dioguardi M, Cocco A, et al. Centering ability of ProTaper Next and WaveOne Classic in J-Shape simulated root canals. Sci World J. 2016;2016.
Wu H, Peng C, Bai Y, et al. Shaping ability of ProTaper Universal, WaveOne and ProTaper Next in simulated L-shaped and S-shaped root canals. BMC Oral health. 2015 Dec;15(1):27.
Pruett JP, Clement DJ Carnes DL, Jr. Cyclic fatigue testing of nickel-titanium endodontic instruments. J Endod. 1997 Feb;23:77-85.
Lim KC, Webber J. The validity of simulated root canals for the investigation of the prepared root canal shape. Int Endod J. 1985 Oct;18:240-246.
Peters OA, Schönenberger K, Laib A. Effects of four Ni–Ti preparation techniques on root canal geometry assessed by micro computed tomography. Int Endod J. 2001 Apr;34:221-30.
Peters OA, Paque F. Root canal preparation of maxillary molars with the self-adjusting file: a micro-computed tomography study. J Endod. 2011 Jan;37:53-57.
Zhao D, Shen Y, Peng B, et al. Root canal preparation of mandibular molars with 3 nickel-titanium rotary instruments: a micro-computed tomographic study. J Endod. 2014 Nov;40:1860-1864.
Shen Y, Zhou HM, Zheng YF, et al. Current challenges and concepts of the thermomechanical treatment of nickeltitanium instruments. J Endod. 2013 Feb;39:163-172.
Pereira ES, Gomes RO, Leroy AM, et al. Mechanical behavior of M-Wire and conventional NiTi wire used to manufacture rotary endodontic instruments. Dent Mater. 2013 Dec;29:e318- e324.
Schäfer E, Vlassis M. Comparative investigation of two rotary nickel-titanium instruments: ProTaper versus RaCe. Part 2. Cleaning effectiveness and shaping ability in severely curved root canals of extracted teeth. Int Endod J. 2004 Apr;37:239-248.
Ha JH, Cheung GS, Versluis A, et al. ‘Screw-in’ tendency of rotary nickel-titanium files due to design geometry. Int Endod J. 2015 Jul;48:666-672.
Bürklein S, Benten S, Schäfer E. Shaping ability of different single-file systems in severely curved root canals of extracted teeth. Int Endod J. 2013 Jul;46:590-597.
Saber SE, Nagy MM, Schäfer E. Comparative evaluation of the shaping ability of WaveOne, Reciproc and OneShape single-file systems in severely curved root canals of extracted teeth. Int Endod J. 2015 Jan;48:109-114.
Elnaghy AM. Cyclic fatigue resistance of ProTaper Next nickeltitanium rotary files. Int Endod J. 2014 Nov;47:1034-1039.
Wu H, Peng C, Bai Y, et al. Shaping ability of ProTaper Universal, WaveOne and ProTaper Next in simulated L-shaped and S-shaped root canals. BMC Oral Health. 2015 Mar; 15:27.
Hülsmann M, Peters OA, Dummer PMH. Mechanical preparation of root canals: shaping goals, techniques and means. Endod Topics. 2005 Aug;10:30-76.
Khalilak Z, Fallahdoost A, Dadresanfar B, et al. Comparison of extracted teeth and simulated resin blocks on apical canal transportation. Iran Endod J. 2008 Fall;3: 109-112.
Saber SE, Nagy MM, Schäfer E. Comparative evaluation of the shaping ability of ProTaper Next, iRaCe and Hyflex CM rotary NiTi files in severely curved root canals. Int Endod J. 2015 Feb;48:131-136.
Lim KC, Webber J. The validity of simulated root canals for the investigation of the prepared root canal shape. Int Endod J. 1985;18(4):240-246.
Carrotte P. Endodontics: Part 4 Morphology of the root canal system. Br Dent J. 2004;197(7):379-383.