The aim of this ex vivo study was to evaluate the effect of using a patency file on apical transportation and curve straightening during canal instrumentation with the ProTaper rotary system. Seventy permanent mandibular first molars with mesiobuccal canals, measuring 18–23？mm in length and with a 25–40° curvature (according to the Schneider method), were selected. The working lengths were determined and the teeth were mounted and divided into two experimental groups: (A) prepared by the ProTaper system without using a patency file ( ) and (B) prepared by the ProTaper system using a patency file ( ). Radiographs taken before and after the preparation were imported into Photoshop software and the apical transportation, and curve straightening were measured. Data were analyzed using independent t-test. Partial correlation analysis was performed to evaluate the relationship between the initial curvature, transportation, and curve straightening ( ). Using a patency file during canal preparation significantly decreased both apical transportation and curve straightening ( ). There were significant relationships between the angle of curvature, transportation and curve straightening in pairs ( ). Apical patency is recommended during root canal preparation with the ProTaper rotary system. 1. Introduction Cleaning and shaping the root canal system is an important step in the success of root canal therapy [1]. Three-dimensional maintenance of the original shape of the root canal is necessary during canal preparation. To achieve this goal, cleaning and shaping should be performed circumferentially, foramen transportation should not occur, and apical foramen should be maintained in its original position [1]. During the root canal instrumentation pulpal and dentinal debris can block the apical third of the root canal, which can increase the chance of ledge formation, transportation, and perforation [2]. These procedural errors can be prevented with the use of a patency file during instrumentation. NiTi rotary instruments obviously decrease several clinical complications, such as canal blockage, ledge formation, transportation, and perforation; they also reduce operator fatigue and the time required for canal preparation [3–6]. ProTaper is one of the NiTi rotary systems, with progressive tapering and a convex triangular cross-sectional cutting blade designed for increased flexibility and cutting efficiency. This system has great applicability in curved canals. Several studies have evaluated canal transportation and curve straightening of ProTaper files. In one study,
References
[1]
H. Schilder, “Cleaning and shaping the root canal,” Dental Clinics of North America, vol. 18, no. 2, pp. 269–296, 1974.
[2]
L. S. Buchanan, “Management of the curved root canal,” Journal of the California Dental Association, vol. 17, no. 4, pp. 18–27, 1989.
[3]
L. Bergmans, J. Van Cleynenbreugel, M. Wevers, and P. Lambrechts, “Mechanical root canal preparation with NiTi rotary instruments: rationale, performance and safety. Status Report for the American Journal of Dentistry,” American Journal of Dentistry, vol. 14, no. 5, pp. 324–333, 2001.
[4]
C. C. R. Ferraz, N. V. Gomes, B. P. F. A. Gomes, A. A. Zaia, F. B. Teixeira, and F. J. Souza-Filho, “Apical extrusion of debris and irrigants using two hand and three engine-driven instrumentation techniques,” International Endodontic Journal, vol. 34, no. 5, pp. 354–358, 2001.
[5]
H. Park, “A comparison of Greater Taper files, ProFiles, and stainless steel files to shape curved root canals,” Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontics, vol. 91, no. 6, pp. 715–718, 2001.
[6]
E. Sch？fer and H. Florek, “Efficiency of rotary nickel-titanium K3 instruments compared with stainless steel hand K-Flexofile. Part 1. Shaping ability in simulated curved canals,” International Endodontic Journal, vol. 36, no. 3, pp. 199–207, 2003.
[7]
S. Y. ？zer, “Comparison of root canal transportation induced by three rotary systems with noncutting tips using computed tomography,” Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology and Endodontology, vol. 111, no. 2, pp. 244–250, 2011.
[8]
M. Veltri, A. Mollo, P. P. Pini, L. F. Ghelli, and P. Balleri, “In vitro comparison of shaping abilities of protaper and gt rotary files,” Journal of Endodontics, vol. 30, no. 3, pp. 163–166, 2004.
[9]
H. H. Javaheri and G. H. Javaheri, “A comparison of three Ni-Ti rotary instruments in apical transportation,” Journal of Endodontics, vol. 33, no. 3, pp. 284–286, 2007.
[10]
R. Gergi, J. A. Rjeily, J. Sader, and A. Naaman, “Comparison of canal transportation and centering ability of twisted files, Pathfile-ProTaper system, and stainless steel hand K-files by using computed tomography,” Journal of Endodontics, vol. 36, no. 5, pp. 904–907, 2010.
[11]
J. G. Cailleteau, “Prevalence of teaching apical patency and various instrumentation and obturation techniques in United States dental schools,” Journal of Endodontics, vol. 23, no. 6, pp. 394–396, 1997.
[12]
F. Goldberg and E. J. Massone, “Patency file and apical transportation: an in vitro study,” Journal of Endodontics, vol. 28, no. 7, pp. 510–511, 2002.
[13]
S. W. Schneider, “A comparison of canal preparations in straight and curved root canals,” Oral Surgery, Oral Medicine, Oral Pathology, vol. 32, no. 2, pp. 271–275, 1971.
[14]
C. M. Bramante, A. Berbert, and R. P. Borges, “A methodology for evaluation of root canal instrumentation,” Journal of Endodontics, vol. 13, no. 5, pp. 243–245, 1987.
[15]
C. E. Del Rio, “Comparison of nickel-titanium and stainless steel hand-file instrumentation using computed tomography,” Journal of Endodontics, vol. 22, no. 7, pp. 369–375, 1996.
[16]
P. Deplazes, O. Peters, and F. Barbakow, “Comparing apical preparations of root canals shaped by nickel-titanium rotary instruments and nickel-titanium hand instruments,” Journal of Endodontics, vol. 27, no. 3, pp. 196–202, 2001.
[17]
N. Imura, A. S. Kato, N. F. Novo, G.-I. Hata, M. Uemura, and T. Toda, “A comparison of mesial molar root canal preparations using two engine-driven instruments and the balanced-force technique,” Journal of Endodontics, vol. 27, no. 10, pp. 627–631, 2001.
[18]
C. A. Backman, R. J. Oswald, and D. L. Pitts, “A radiographic comparison of two root canal instrumentation techniques,” Journal of Endodontics, vol. 18, no. 1, pp. 19–24, 1992.
[19]
G. B. Sydney, A. Batista, and L. L. de Melo, “The radiographic platform: a new method to evaluate root canal preparation in vitro,” Journal of Endodontics, vol. 17, no. 11, pp. 570–572, 1991.
[20]
M. Hülsmann and F. Stryga, “Comparison of root canal preparation using different automated devices and hand instrumentation,” Journal of Endodontics, vol. 19, no. 3, pp. 141–145, 1993.
[21]
M.-K. Wu, “Leakage along apical root fillings in curved root canals. Part I: effects of apical transportation on seal of root fillings,” Journal of Endodontics, vol. 26, no. 4, pp. 210–216, 2000.
[22]
O. A. Peters, C. I. Peters, K. Sch？nenberger, and F. Barbakow, “ProTaper rotary root canal preparation: effects of canal anatomy on final shape analysed by micro CT,” International Endodontic Journal, vol. 36, no. 2, pp. 86–92, 2003.
[23]
Y. Gao, O. A. Peters, H. Wu, and X. Zhou, “An application framework of three-dimensional reconstruction and measurement for endodontic research,” Journal of Endodontics, vol. 35, no. 2, pp. 269–274, 2009.
[24]
R. A. Bernardes, E. A. Rocha, M. A. H. Duarte et al., “Root canal area increase promoted by the EndoSequence and ProTaper systems: comparison by computed tomography,” Journal of Endodontics, vol. 36, no. 7, pp. 1179–1182, 2010.
[25]
M. T. Sberna, G. Rizzo, E. Zacchi, P. Capparè, and A. Rubinacci, “A preliminary study of the use of peripheral quantitative computed tomography for investigating root canal anatomy,” International Endodontic Journal, vol. 42, no. 1, pp. 66–75, 2009.
[26]
A. Guelzow, O. Stamm, P. Martus, and A. M. Kielbassa, “Comparative study of six rotary nickel-titanium systems and hand instrumentation for root canal preparation,” International Endodontic Journal, vol. 38, no. 10, pp. 743–752, 2005.
[27]
Y. Yoshimine, M. Ono, and A. Akamine, “The shaping effects of three nickel-titanium rotary instruments in simulated S-shaped canals,” Journal of Endodontics, vol. 31, no. 5, pp. 373–375, 2005.
[28]
J. H. Gutiérrez, C. Brizuela, and E. Villota, “Human teeth with periapical pathosis after overinstrumentation and overfilling of the root canals: a scanning electron microscopic study,” International Endodontic Journal, vol. 32, no. 1, pp. 40–48, 1999.
[29]
J. A. Gonzalez Sanchez, F. Duran-Sindreu, M. Albuquerque Matos et al., “Apical transportation created using three different patency instruments,” International Endodontic Journal, vol. 43, no. 7, pp. 560–564, 2010.
[30]
S. M. Hasheminia and M. Shafiee Ardestani, “The effect of using patency file on apical transportation in canals prepared with passive step back technique,” Journal of Research in Medical Sciences, vol. 9, no. 5, pp. 12–17, 2004.
[31]
I. Tsesis, B. Amdor, A. Tamse, and A. Kfir, “The effect of maintaining apical patency on canal transportation,” International Endodontic Journal, vol. 41, no. 5, pp. 431–435, 2008.
[32]
S. A. Thompson and P. M. H. Dummer, “Shaping ability of lightspeed rotary nickel-titanium instruments in simulated root canals. Part 1,” Journal of Endodontics, vol. 23, no. 11, pp. 698–702, 1997.
[33]
S. A. Thompson, “Shaping ability of lightspeed rotary nickel-titanium instruments in simulated root canals. Part 2,” Journal of Endodontics, vol. 23, no. 12, pp. 742–747, 1997.
[34]
S. A. Thompson and P. M. H. Dummer, “Shaping ability of Hero 642 rotary nickel-titanium instruments in simulated root canals: part 2,” International Endodontic Journal, vol. 33, no. 3, pp. 255–261, 2000.
[35]
S. A. Thompson and P. M. H. Dummer, “Shaping ability of Hero 642 rotary nickel-titanium instruments in simulated root canals: part 1,” International Endodontic Journal, vol. 33, no. 3, pp. 248–254, 2000.
[36]
S. T. Bryant, P. M. H. Dummer, C. Pitoni, M. Bourba, and M. Moghal, “Shaping ability of .04 and .06 taper ProFile rotary nickel-titanium instruments in simulated root canals,” International Endodontic Journal, vol. 32, no. 3, pp. 155–164, 1999.
[37]
S. T. Bryant, S. A. Thompson, M. A. O. Al-Omari, and P. M. H. Dummer, “Shaping ability of ProFile rotary nickel-titanium instruments with ISO sized tips in simulated root canals: part 2,” International Endodontic Journal, vol. 31, no. 4, pp. 282–289, 1998.
[38]
S. T. Bryant, S. A. Thompson, M. A. O. Al-Omari, and P. M. H. Dummer, “Shaping ability of Profile rotary nickel-titanium instruments with ISO sized tips in simulated root canals: part 1,” International Endodontic Journal, vol. 31, no. 4, pp. 275–281, 1998.
[39]
I. T. Griffiths, S. T. Bryant, and P. M. H. Dummer, “Canal shapes produced sequentially during instrumentation with Quantec LX rotary nickel-titanium instruments: a study in simulated canals,” International Endodontic Journal, vol. 33, no. 4, pp. 346–354, 2000.
[40]
I. T. Griffiths, A. L. Chassot, M. F. Nascimento, S. T. Bryant, and P. M. H. Dummer, “Canal shapes produced sequentially during instrumentation with Quantec SC rotary nickel-titanium instruments: a study in simulated canals,” International Endodontic Journal, vol. 34, no. 2, pp. 107–112, 2001.
[41]
J. M. Campos and C. del Rio, “Comparison of mechanical and standard hand instrumentation techniques in curved root canals,” Journal of Endodontics, vol. 16, no. 5, pp. 230–234, 1990.
