Influence of single-file endodontics on apical transportation in curved root canals: an ex vivo micro-computed tomographic study.
BACKGROUND
More information regarding the ability of single files to maintain the original canal position is required before adopting a single-file approach to cleaning and shaping. This study compares apical transportation in curved root canals when instrumenting with a single WaveOne (WO) file (Dentsply Tulsa Dental Specialties, Tulsa, OK) in a reciprocating motion with that incurred when using a sequence of Twisted Files (TFs; SybronEndo, Orange, CA) in a continuous rotating motion.


METHODS
Forty mesial canals of mandibular molars were evenly allocated into 2 balanced groups (n = 20) with a 17-mm average canal length and 20° average curvature. Canals were accessed in a conventional manner and instrumentation was completed with a single WO file or a series of TFs. The canals were instrumented according to the manufacturers' protocol. Apical transportation was assessed on a comparison of the pre- and postinstrumentation micro-computed tomographic scans at 1-, 2-, 3-, 4-, and 5-mm sections. One-way analysis of variance was performed to assess if a significant difference between systems exists.


RESULTS
No significant difference (P > .05) was found between the WO and TF groups. Transportation in the mesial direction was of greater magnitude than distal transportation for both files systems. The mean transportation in the mesial direction was 100.1 ± 8.8 μm (WO group) and 101.0 ± 10.9 μm (TF group) (P = .5), whereas distal transportation was found to be 80.9 ± 14.6 μm (WO group) and 60.3 ± 11.0 μm (TF group) (P = .3).


CONCLUSIONS
The results suggest that no difference exists between the WO file system and the conventional multifile TF system when considering apical transportation in curved canals.
University of Manitoba, Winnipeg, Manitoba, Canada.
Alanna
A
Junaid
University of Sao Paulo, Sao Paulo, Sao Paulo, Brazil.
Laila Gonzales
LG
Freire
Centre for Dental Research, Sao Leopoldo Mandic, Campinas, Sao Paulo, Brazil.
Carlos Eduardo
CE
da Silveira Bueno
Department of Restorative Dentistry, University of Manitoba, Winnipeg, Manitoba, Canada.
Isabel
I
Mello
Department of Restorative Dentistry, University of Manitoba, Winnipeg, Manitoba, Canada. Electronic address: rodrigo.cunha@ad.umanitoba.ca.
Rodrigo Sanches
RS
Cunha
D019412:Anatomy, Cross-Sectional / Q000379:methods; D003786:Dental Pulp Cavity / Q000000981:diagnostic imaging*; D004867:Equipment Design; D006801:Humans; D066298:In Vitro Techniques; D008963:Molar / Q000000981:diagnostic imaging; D011897:Random Allocation; D012388:Root Canal Irrigants / Q000627:therapeutic use; D018915:Root Canal Preparation / Q000295:instrumentation*; D012399:Rotation; D012973:Sodium Hypochlorite / Q000627:therapeutic use; D007507:Therapeutic Irrigation / Q000379:methods; D019227:Tooth Apex / Q000000981:diagnostic imaging*; D055114:X-Ray Microtomography / Q000379:methods*
D012388:Root Canal Irrigants; D012973:Sodium Hypochlorite
Continuous rotating motion; micro–computed tomography; reciprocating motion; root canal preparation; transportation