title: Preference of undergraduate students after first experience on nickel-titanium endodontic instruments.
abstract: OBJECTIVE
  This study aimed to compare two nickel-titanium systems (rotary vs. reciprocating) for their acceptance by undergraduate students who experienced nickel-titanium (NiTi) instruments for the first time.
  
  
  METHODS
  Eighty-one sophomore dental students were first taught on manual root canal preparation with stainless-steel files. After that, they were instructed on the use of ProTaper Universal system (PTU, Dentsply Maillefer), then the WaveOne (WO, Dentsply Maillefer). They practiced with each system on 2 extracted molars, before using those files to shape the buccal or mesial canals of additional first molars. A questionnaire was completed after using each file system, seeking students' perception about 'Ease of use', 'Flexibility', 'Cutting-efficiency', 'Screwing-effect', 'Feeling-safety', and 'Instrumentation-time' of the NiTi files, relative to stainless-steel instrumentation, on a 5-point Likert-type scale. They were also requested to indicate their preference between the two systems. Data was compared between groups using t-test, and with Chi-square test for correlation of each perception value with the preferred choice (p = 0.05).
  
  
  RESULTS
  Among the 81 students, 55 indicated their preferred file system as WO and 22 as PTU. All scores were greater than 4 (better) for both systems, compared with stainless-steel files, except for 'Screwing-effect' for PTU. The scores for WO in the categories of 'Flexibility', 'Screwing-effect', and 'Feeling-safety' were significantly higher scores than those of PTU. A significant association between the 'Screwing-effect' and students' preference for WO was observed.
  
  
  CONCLUSIONS
  Novice operators preferred nickel-titanium instruments to stainless-steel, and majority of them opted for reciprocating file instead of continuous rotating system.
authors: Department of Conservative Dentistry, School of Dentistry, Pusan National University, Dental Research Institute, Yangsan, Korea.
authors: Sang Won
authors: SW
authors: Kwak
authors: Area of Endodontics, Faculty of Dentistry, the University of Hong Kong, Hong Kong SAR, China.
authors: Gary Shun-Pan
authors: GS
authors: Cheung
authors: Department of Conservative Dentistry, School of Dentistry, Kyungpook National University, Daegu, Korea.
authors: Jung-Hong
authors: JH
authors: Ha
authors: Department of Conservative Dentistry, School of Dentistry, Kyungpook National University, Daegu, Korea.
authors: Sung Kyo
authors: SK
authors: Kim
authors: Climate Research Department, APEC Climate Center, Busan, Korea.
authors: Hyojin
authors: H
authors: Lee
authors: Department of Conservative Dentistry, School of Dentistry, Pusan National University, Dental Research Institute, Yangsan, Korea.
authors: Hyeon-Cheol
authors: 0000-0001-8032-1194
authors: HC
authors: Kim
keywords: Nickel-titanium file; Preference; Reciprocating; Rotary; Undergraduate student