title: Shaping ability of ProTaper Universal, WaveOne and ProTaper Next in simulated L-shaped and S-shaped root canals.
abstract: BACKGROUND
  The purpose of this study was to compare the shaping ability of the ProTaper Universal (PTU; Dentsply Maillefer, Ballaigues, Switzerland), WaveOne (WO; Dentsply Maillefer) and ProTaper Next (PTN; Dentsply Maillefer) in simulated L-shaped and S-shaped root canals respectively.
  
  
  METHODS
  30 simulated L-shaped and 30 simulated S-shaped root canals in resin blocks were employed and randomly divided into 3 groups (n = 10), respectively. The canals were prepared to a tip size 25 using PTU, WO or PTN: PTU F2 (taper 0.08 over the first 3 mm from apical tip), WO Primary (taper 0.08 over the first 3 mm from apical tip), and PTN X2 (taper 0.06 over the first 3 mm from apical tip). Photos of the simulated root canals were taken pre- and postinstrumentation. The 2 layers were superimposed after a series of image processing and 10 points were selected from apical constriction with 1 mm interval. And then the central axis transportation and straightened curvature were measured with software of image analysis.
  
  
  RESULTS
  In simulated L-shaped root canals, PTU and PTN caused less transportation than WO at curved section (P < 0.05), and PTN caused the least transportation at apical constriction (P < 0.05). Moreover, PTN maintained the canal curvature best among the 3 groups (P < 0.05). But PTN produced more transportation at straight section compared with PTU and WO (P < 0.05). In simulated S-shaped root canals, PTN preserved the coronal curvature best (P < 0.05), but there was no significant difference in apical curvature since all the files straightened the curvature obviously.
  
  
  CONCLUSIONS
  PTN showed a better shaping ability than PTU and WO at the curved section of root canals, and PTN maintained the best apical constriction. But all the files had a tendency to straighten the apical curvature in multi-curved canals.
authors.affiliation: School of Stomatology, Tianjin Medical University, #12 Qi Xiang Tai Road, He Ping District, Tianjin, 300070, PR China. 34384751@qq.com.
authors.forename: Hui
authors.initials: H
authors.lastname: Wu
authors.affiliation: School of Stomatology, Tianjin Medical University, #12 Qi Xiang Tai Road, He Ping District, Tianjin, 300070, PR China. Peng_cheng2013@163.com.|Department of Stomatology, The Second Hospital of Tianjin Medical University, Tianjin Medical University, Tianjin, China. Peng_cheng2013@163.com.
authors.forename: Cheng
authors.initials: C
authors.lastname: Peng
authors.affiliation: School of Stomatology, Tianjin Medical University, #12 Qi Xiang Tai Road, He Ping District, Tianjin, 300070, PR China. 108108550@qq.com.
authors.forename: Yulong
authors.initials: Y
authors.lastname: Bai
authors.affiliation: School of Stomatology, Tianjin Medical University, #12 Qi Xiang Tai Road, He Ping District, Tianjin, 300070, PR China. huxin90@126.com.
authors.forename: Xin
authors.initials: X
authors.lastname: Hu
authors.affiliation: School of Stomatology, Tianjin Medical University, #12 Qi Xiang Tai Road, He Ping District, Tianjin, 300070, PR China. 15822680967@163.com.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: School of Stomatology, Tianjin Medical University, #12 Qi Xiang Tai Road, He Ping District, Tianjin, 300070, PR China. changyi_li@sina.com.
authors.forename: Changyi
authors.initials: C
authors.lastname: Li
mesh_terms: D004396:Coloring Agents; D003722:Dental Alloys / Q000737:chemistry; D003786:Dental Pulp Cavity / Q000033:anatomy & histology*; D004867:Equipment Design; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008422:Materials Testing; D008953:Models, Anatomic; D009532:Nickel / Q000737:chemistry; D010781:Photography / Q000379:methods; D011897:Random Allocation; D018915:Root Canal Preparation / Q000295:instrumentation*; D012399:Rotation; D014025:Titanium / Q000737:chemistry; D019227:Tooth Apex / Q000033:anatomy & histology; D019415:Torque
chemical_list: D004396:Coloring Agents; D003722:Dental Alloys; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium