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Dentine chips produced by nickel‐titanium rotary instruments
Author(s) -
Guppy D. R.,
Curtis R. V.,
Ford T. R. Pitt
Publication year - 2000
Publication title -
dental traumatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 81
eISSN - 1600-9657
pISSN - 1600-4469
DOI - 10.1034/j.1600-9657.2000.016006258.x
Subject(s) - roundness (object) , reamer , dental instruments , materials science , root canal , nickel titanium , biomedical engineering , dentistry , orthodontics , composite material , metallurgy , medicine , shape memory alloy
– This study aimed to compare the cross‐sectional shape of two nickel‐titanium rotary instruments, namely ProFile and Quantec files, both ISO 25, 0.06 taper, and sought to relate this to the chips produced by cutting dentine. A limited comparison was made with stainless steel engine reamers. First, five files of each type were sectioned transversely at 12 mm, 8 mm and 4 mm from the tip and examined by scanning electron microscopy. The cutting angles were assessed by a direct measurement technique which allowed for the inclination of a cutting edge to the root canal. Second, eight samples of cutting debris were collected from instrumentation by each type of nickel‐titanium file and four samples from the engine reamers. The major and minor axis, area and roundness of the dentine chips in each sample were measured using computerized particle analysis. The results demonstrated that all files had a negative cutting angle which varied at the different levels (ProFiles range 69.4° to 58.4° and Quantec range 74.8° to 56.8°). The consistency within files of the same type was good as demonstrated by low standard deviations, except for Quantec files at the 4 mm level where higher standard deviations of 4.1° and 5.5° for the two blades were found. The chip analysis showed significant differences between chips produced by ProFile and Quantec files ( P <0.05). The latter were larger and rounder. The chips from the ProFile and the engine reamer chips were similar in dimension ( P >0.05). No simple relationship existed between file geometry and the dentine chips produced during instrumentation.