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HyFlex CM File

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HyFlex CM

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HyFlex CM File

  1. 1. One of the primary goals of endodontic therapy is the complete debridement of pulp tissue from the canal, coupled with shaping of the root canal system. The ability to enlarge a canal without deviation from the original canal curvature is a primary objective in endodontic instrumentation. Introduction Standard Nickel Titanium rotary endodontic files, because of their shape memory property and larger tapers can often not serve well for complicated cases such as those with very fine and curved canals.
  2. 2. NiTi is a shape-memory alloy also commonly referred to by the name Nitinol, derived from its place of discovery, the Nickel Titanium Naval Ordinance Laboratory. William Buehler, along with Frederick Wang, discovered its properties during research in 1962. The discovery of the shape-memory effect dates to 1932, when Swedish researcher Arne Olander first observed the property in gold-cadmium alloys. The material, if deformed while cool, returns to its undeformed shape when warmed.
  3. 3. Nitinol shape-memory alloys undergo a phase transformation in their crystal structure when cooled from the stronger, high temperature form (austenite) to the weaker, low temperature form (martensite).* How does Nitinol work? *Austenite: it is quite strong and hard. Martensite: it is soft and ductile, and it can be easily deformed. Stress-induced martensite (superelastic): it is highly elastic (rubber-like).
  4. 4. This inherent phase transformation is the basis for the unique properties of these alloys-in particular, shape memory and super elasticity.
  5. 5. Eventually a concept emerged which revolutionized the technology of rotary endodontic files, which was based on ‘Controlled memory’ in contrast to the classical ‘Shape memory’ one. A new Nitinol rotary instrument files with controlled memory (HyFlex® CM, Coltene) was introduced by Riacrdo Caiecedo & Stephen Clark in 2011, which was machined from a wire termed (CM-wire) previously subjected to a proprietary, novel, thermomechanical processing procedure. Clinical and experimental studies have indicated that these new HyFlex® CM rotary instruments have outstanding clinical fatigue resistance. HyFlex CM file
  6. 6. The Controlled memory effect helps the file to retain the shape of the canal even when it is out of the canal. This property is responsible for avoiding procedural errors such as ledge formation, transportation, perforations etc. The extreme flexibility and lesser taper of these files make them very advantageous in curved canal cases.
  7. 7. File Design • ISO color coded on handle-indicates size of file, diameter [mm] at the tip, assortment (19mm, 21mm, 25mm, 31mm lengths). • Printed number indicates degree of taper. • Accelerated flute design provides excellent flexibility, tip strength and debris transportation. • Positive rake angle* (except for orifice opener neutral) for efficient cutting properties. •rake angle is the angle between the leading edge of a cutting tool and perpendicular to the surface being cut.
  8. 8. • Non-active tip of file. • 2 cutting blades. • Sizes of files have 3 tapers 0.04, 0.06, 0.08 • Cross section was double fluted Hedstroem design, 2 cutting blades.
  9. 9. Features of File 1. Unique NiTi wire treatment that controls the material’s memory makes the file extremely flexible without rebound providing superior canal tracking thus virtually eliminates these typical problems with other files such as:
  10. 10. Superior Flexibility + No Rebound = Superior Tracking Standard NiTi File Material Hyflex CM NiTi file Material
  11. 11. 2. Unique NiTi wire treatment controls the material’s memory making the file Up to 339% higher fatigue resistance than standard NiTi files Benefits • Virtually eliminates instrument separation. • File unwinds before it separates, this provides a clear visual warning to remove.
  12. 12. 4. Controlled Memory (HyFlex CM) files , retain their shape in curved canals and do not possess the ‘Spring back action’, thereby avoiding any perforation.
  13. 13. 3. Additional file features: • Increasingly wider flutes provides efficient debris transportation & prevents file from “screwing” into the canal. •Absence of radial lands allows the instrument to be sharper and consequently more efficient. *Pitch is the distance between a point on the leading edge and the corresponding point on the adjacent leading edge. • Accelerated Flute Design (Variable pitch)*.
  14. 14. • The conventional NiTi files have another drawback of not giving a ‘warning sign’ before breakage (unlike stainless steel files, which show such signs in the form of unwinding of flutes, or presence of a shiny spot on the file, indicating that the file should be discarded). HyFlex files have overcome this problem with the unique characteristic of rewinding of the file after autoclaving. • If the file does not rewind, it indicates that it needs to be discarded. This is a very useful criteria for the clinician to decide when to discard the file.
  15. 15. The following are general recommendations for the instrumentation process: • Sterilize files prior to use. • Operate the handpiece at 500 rpm. Recommended torque setting is up to 2.5 N.cm. • Instruments need to be inspected before and after use. • Recapitulate between each step with the patency file. • Irrigate/lubricate the canal frequently when using the files. • Clean file flutes after each insertion into the root canal. • The number of times the instruments can be reused is dependent on treatment and procedure.
  16. 16. An advantage of HyFlex® CM files is that they can be used with multiple techniques (crown-down, step-back) or with the single- length technique proposed by the manufacturer:
  17. 17. Fatigue Resistance: • HyFlex CM showed the highest resistance to fracture than ProTaper Universal and ProTaper next. Some of studies on HyFlex CM file Apical Extrusion of Debris: • Reciprocating files (WaveOne and RECIPROC) had more extrusion than HyFlex CM. • HyFlex CM had significantly less debris extrusion than the ProTaper Next. Dentinal Cracks: • HyFlex CM had less dentinal crack than the ProTaper Universal and ProTaper Next.