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Deformation of HyFlex CM instruments and their shape recovery following heat sterilization
Author(s) -
Alfoqom Alazemi M.,
Bryant S. T.,
Dummer P. M. H.
Publication year - 2015
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 - 10.1111/iej.12353
Subject(s) - sterilization (economics) , magnification , materials science , dental instruments , medicine , dentistry , biomedical engineering , computer science , artificial intelligence , monetary economics , economics , foreign exchange market , foreign exchange
Aim To assess the deformation of HyFlex CM instruments (Coltene Whaledent) when used in two instrumentation sequences and to assess their shape recovery after heat sterilization. Methodology Simulated root canals with four different shapes were prepared with HyFlex CM instruments using a single‐length technique ( n = 40) or a crown down technique ( n = 40). Pre‐preparation, post‐preparation and post‐sterilization standardized images of each instrument were recorded. Assessment of instrument deformation and their subsequent shape recovery was carried out visually and by comparing the digitised images. Data analysis was carried out using chi‐square tests. Results None of the 400 instruments fractured. Visual assessment of instruments post‐preparation revealed that 30.5% had unwound and 0.5% had reverse winding. Following sterilization 8.5% remained unwound and 0.5% remained with reverse winding. When assessing instrument shape using digital images, 35.25% were unwound post‐preparation, which reduced to 11% post‐sterilization. Nine size 25, 0.08 instruments deformed, but none fully regained their original shape after sterilization; however, other sizes of deformed instruments did regain their shape ( P < 0.001). Conclusion Approximately one third of instruments became deformed as a result of use. However, two thirds of these fully recovered their shape following sterilization. The number of deformed instruments was underestimated when no magnification was used for assessment. Instrument size was related to incidence of deformation and shape recovery.