In vitro comparison in a manikin model: increasing apical enlargement with K3 and K3XF rotary instruments.
INTRODUCTION
The aim of the study was to compare the K3 and K3XF systems (SybronEndo, Glendora, CA) after 1 and 2 uses by evaluating apical transportation, working length loss, and working time in a manikin model.


METHODS
Mesial canals of 40 extracted first mandibular molars were instrumented. Radiographs taken after instrumentation with #25, #30, #35, and #40 files were superimposed on the preoperative image in both mesiodistal and buccolingual angulations. AutoCAD (Autodesk Inc, San Rafael, CA) was used to measure working length loss and apical transportation at 0, 0.5, and 1 mm from the working length (WL). The working time was measured. Group comparison was analyzed using post hoc Tukey honestly significant difference tests (P < .05).


RESULTS
No significant differences were found in apical transportation, working length loss between K3 and K3XF systems, or between the number of uses. Significant differences were found when canal enlargement was performed to a #35-40 (P < .05). K3 instrumentation performed significantly faster (29.6 ± 15.4) than with the K3XF system (40.2 ± 17.7) (P < .05). No differences were observed in working time when comparing the number of uses.


CONCLUSIONS
K3 and R-phase K3XF rotary systems shaped curved root canals safely with minimal apical transportation, even up to a 40/04 file.
['Olivieri|Juan Gonzalo|JG|', 'Stöber|Eva|E|', 'García Font|Marc|M|', 'González|Jose Antonio|JA|', 'Bragado|Pablo|P|', 'Roig|Miguel|M|', 'Duran-Sindreu|Fernando|F|']
D003754:Dental High-Speed Equipment D003786:Dental Pulp Cavity D018130:Diamond D006801:Humans D007091:Image Processing, Computer-Assisted D008348:Manikins D008422:Materials Testing D008963:Molar D009811:Odontometry D011859:Radiography D018915:Root Canal Preparation D012399:Rotation D013997:Time Factors D019227:Tooth Apex D019415:Torque
manikin increased apical enlargement K3 K3XF Apical transportation R-phase root canal preparation