Rotatable Endodontic Instruments and Methods for their Manufacture
OwnerEvgueniy A. Rzhanov, Anatoliy E. Rzhanovinventors
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Abstract
A quasi-hyperbolic endodontic instrument having a cylindrical, elongated shaft with a radius that varies as a smooth, continuous curve along the length of the shaft and is larger near the distal portion of the file than near the proximal end of the file. The distal radius may be 10% or more larger than the proximal radius. This design provides a flexible file that minimizes the possibility of breaking, and ensures that if breakage does occur, it will occur near the handle, allowing the broken bit to be easily removed from the tooth canal. The instrument may further, or instead, have a metal cable connecting the cutting head to the handle to help reduce metal fatigue.
Claims10
A quasi-hyperbolic endodontic instrument, comprising:
- an elongated shaft, made of metal, and having a distal end, a proximal end and a rotational axis extending from said distal end to said proximal end, said shaft being machined to comprise:
- a working portion, located proximate to the distal end of said elongated shaft and extending along no more than one-third of said elongated shaft, and shaped to provide at least one cutting surface;
- a capture node, located proximate to the proximal end of said elongated shaft, said capture node having an effective radius at least 10% larger than the radius of the shaft proximate to the capture node, and an outer surface having at least one substantially flat facet;
- and
- wherein the radius of said elongated shaft varies from the end of said working portion to said capture node in a smooth, continuous curve, and is at least 10% larger proximate to said working portion than in the region proximate to said capture node and between said capture node and said working portion, and wherein said shaft has a region of weakest torsional rigidity located proximate to said capture node and between said capture node and the proximal end of said elongated shaft.
A cable endodontic file, comprising:
- a cable comprising at least seven strands of metal wire having substantially equal lengths, and having six of said strands helically wound around the seventh strand, thereby forming said cable having a proximal end, a distal end and an axis of rotation extending from said distal end to said proximal end;
- a cutting head fixedly attached to the distal end of said cable, said cutting head having at least one cutting surface;
- and
- a handle comprising a metal tube enclosing part of said cable and being fixedly attached the proximal end to said cable, and wherein the unenclosed portion of the cable extends at least one third of the length of the combined cable and the enclosing metal tube.
Dependencies are inferred from the claim text.