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Canal shapes produced sequentially during instrumentation with Quantec LX rotary nickel‐titanium instruments: a study in simulated canals
Author(s) -
Griffiths I. T.,
Bryant S. T.,
Dummer P. M. H.
Publication year - 2000
Publication title -
international endodontic journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.988
H-Index - 119
eISSN - 1365-2591
pISSN - 0143-2885
DOI - 10.1046/j.1365-2591.2000.00311.x
Subject(s) - root canal , nickel titanium , instrumentation (computer programming) , materials science , point (geometry) , position (finance) , dental instruments , biomedical engineering , mathematics , dentistry , computer science , engineering , composite material , medicine , geometry , finance , shape memory alloy , economics , operating system
Aim The aim of this study was to determine the shaping ability of Quantec LX nickel‐titanium rotary instruments in simulated root canals. Methodology Forty simulated canals consisting of four different shapes in terms of angle and position of curvature were prepared with Quantec LX instruments. Sequential still images were taken of the canals using a video camera attached to a computer with image analysis software. Images were taken preoperatively; after, instrument 7 (Size 25, 0.05 taper), instrument 8 (size 25, 0.06 taper), and instrument 10 (size 45, 0.02 taper) were taken to length. Each sequential postoperative image was superimposed individually over the preoperative image in order to highlight the amount and position of material removed during preparation. Intra‐canal impressions after preparation to size 10 were taken to evaluate three‐dimensional canal form. Results Overall, the mean preparation time to size 10 was 4.7 min; canal shape did not have a significant effect on speed of preparation. No instruments fractured within the canal, but 7 instruments separated from the latch grip, and a further 3 instruments deformed. All canals remained patent. Following preparation to size 10, 29 canals (72%) retained their length, 7 (17%) lost length, and 4 gained length; the magnitude of the change in length was always below 1 mm. Zips were created in 3 canals (7%) after use of size 10 instruments, but no perforations or danger zones were produced. Excess removal of material along the outer aspect of the curve between the beginning of the curve and the end‐point (outer widening) was found in 22 canals (55%) after instrument 7, in 30 (75%) canals after size 8 and in 35 canals (88%) after size 10. There was a significant difference ( P < 0.0001) between canal shapes for the incidence of this aberration at all sizes. Conclusions Under the conditions of the study, Quantec LX instruments tended to remove excess material from the outside of the curve between the beginning of the curve and the end‐point. These aberrations increased in prevalence and severity following the use of larger instruments when they were taken to length. Size 8, 9 and 10 Quantec LX instruments should be used with care and short of length, especially in severely curved canals.