![]() ![]() Accurate working length determination and adherence is of paramount importance in rotary endodontics.Do not use the entire length of the file for cutting as it has a higher potential for fracture.Over using files results in decreased efficiency and increases risk of breakage.Canals with difficult anatomy should be instrumented with hand files prior to rotary instrumentation.Do no force rotary files as they are to be used with a passive technique.Adequate access to the canals is crucial when using NiTi rotary files in biomechanical preparation.Things to keep in mind while using rotary files: Fewer cases of broken instruments, perforations and ledgesĪ comparison of the features of a few commonly used rotary files have been tabulated below:. ![]() Greater resistance to torsional fractures.Higher capacity to withstand stress – 1000% more than stainless steel.Elastic flexibility – 500% more stainless steel.Nickel Titanium has been the material of choice in manufacturing rotary files due to their superior properties. The introduction of rotary files to the field of endodontics came two decades ago and the research and advancements are never-ending. Rotary endodontic practices have gained immense popularity among dental practitioners as they have many advantages over traditional manual instrumentation methods. When the Dentists mastered the method of the using the products for rotary shaping instruments they could see unpredictable file breakage, metal fatigue, variation in length, loss of cutting efficiency, diameter and curvature of the canal can be avoided and better shaping of the canals with deserved taper will be achieved. Rotary shaping instruments are replacing the conventional hand file systems to enhance the shaping ability of the canal, reducing clinical mishaps like blocks, ledges, transportation, and perforation. Modifications of H files such as Safety Hedstroem files, Hyflex files, Unifiles and S files have been designed and manufactured.Ī Nickel Titanium (NiTi) rotary file is an engine-driven, pointed and tapered endodontic instrument made of Nickel Titanium alloy with cutting edges used to mechanically prepare and shape the root canals during endodontic therapy or to remove the root canal obturating material while performing retreatment. Hence H files are to be used in filing motion only. The cross section of a H file can be seen as a “tear drop” with one cutting edge.Ĭare should be taken to not use H files in reaming motion because, the instrument design renders the shaft of the instrument at the junction of two cones weak, facilitating breakage. Due to this design H files cut root dentin only during the pulling stroke. The base of these cones have sharp edges ad function as cutting edges of the file. H files or Hedstrom files are fabricated by machine grinding a round stainless steel wire into a series of intersecting cones. Some modifications of K files include K-Flex files and Flex-R files Counter clockwise rotation leads to brittle fracture.Clockwise rotation leads to unwinding and ductile fracture.When a K file is locked inside the root canals – K files are used in filing and reaming actions. The number of flutes can range from 1.5-2.5 per millimeter. The wire is now twisted in a counter clockwise direction to form flutes. ![]() K file fabrication begins by cutting a round SS wire to form a tapered instrument having a square cross-section and pointed tips. K files were first produced by the Kerr Manufacturing Company. Endodontic hand files are placed under Group 1 under the general classification of endodontic instruments. But stainless steel and nickel titanium were used as the material used for manufacture of endodontic files as they were more flexible and had lesser chances of fracture. Initially hand files were made of carbon steel. Although before 1958 hand files were manufactured according to the manufacturers’ whim, standardization in the length, taper, cutting blades and other aspects were proposed by Ingle and Levine. Rotary endodontic files are used with handpieces powered by endomotors to automate the process of canal preparation.Įndodontic hand files are manually operated instruments used in biomechanical preparation of the root canal. The hand-operated or manual endodontic files are used with filing, reaming, rasping or pulling motions to remove the root canal dentin. Endodontic files can be grouped under two major heads based on their mode of use as, hand-operated or rotary files. ![]()
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