Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C5/00—Filling or capping teeth
  • A61C5/40—Implements for surgical treatment of the roots or nerves of the teeth; Nerve needles; Methods or instruments for medication of the roots
  • A61C5/42—Files for root canals; Handgrips or guiding means therefor

Definitions

• Root canal file and method of manufacturing it.
• the present invention relates to a root canal file and to a method of manufacturing such a file.
• Root canal files are used by dentists for widening the root canal of a tooth at treatments of the root.
• Hedstr ⁇ m file or H-file is manufactured by grinding a helical groove 3 having a special shape as shown in fig. 1 and 2 in a tapered file blank, so that the outer edges of the groove are forming a helical cutting edge 2 of the file.
• the two other previously known files are manufactured by first grinding the file blank to a quadrangular or triangular cross section, whereupon the file blank is twisted, so that the edges of the quadrangular or triangular file blank are forming cutting edges which extend helically along the periphery of the file. It can also be grinded in helical cross section.
• the above mentioned previously known files have different characteristics and partly different functions, and in clearing root canals it is often necessary to use both files.
• the so-called K-file forms in its weaker design * a fine, light and flexible root canal instrument which is used as "path ⁇ finder". It is moved by spiral movement down into the root canal.
• the cutting edges of the K-file are, however, not very keen and the capacity of the file of removing material is small, and therefore the so-called H-file is used for widening the root canal after a small passage being formed down into the root canal by the K-file.
• the H-file has large capacity of removing material in the root canal but it has difficulties in finding its way down through the root canal if this has not been prepared by a K-file.
• the purpose of the present invention is to provide a new ty of root canal file which is intended to replace the above described, previously known files as well as a new method o manufacturing this new type of root canal file.
• a root canal file wherein the working part presents two, helically along the working part extending,continous cutting edgeswhich are displaced in rela to each other in the longitudinal direction of the working part, so that each turn in one of the helices is situated between two turns following after each other of the other cutting edge helix
• a method of manufacturing such a root canal file wherein two continous, helically extendi grooves are grinded in the outer surface of a file blank, which grooves are displaced in relation to each other in th longitudinal direction of the file blank, so that each helix turn of one of the grooves is situated between two helix turns following after each other of the other groove and so that the outer edges of the grooves are forming two continous, along the file blank helically extending cutting edges which are displaced in relation to each other along th longitudinal direction of the file blank.
• a root canal file which, on one hand,is so flexible and of such a strength that can be moved down also into curved root canals without being broken and which, on the other hand, has large capacity of removing material in the root canal.
• fig. 1 shows the working part of a previously known root canal file, cf. above
• fig. 2 a portion of the working part of such a previously known root canal file in enlarged scale and partly in cross section through the longitudinal ax ⁇ s of the root canal file and a cross section of the working part through the plane B-B
• fig. 3 an embodiment of the working part of the root canal file according to the invention
• fig. 4 a portion of the working part in fig.3 in enlarged scale and partly in cross section along the longitudinal axis of the root canal file and a cross section of the working part through the plane A-A
• fig. 5 an enlarged view of a part of the working part in fig. 3, fig.
• fig. 6 a portion of the working part in fig. 3 in a cross section along the longitudinal axis of the root canal file
• fig. 7 an enlarged view of a part of fig. 6,
• fig. 8 a schematic view of the working part of a root canal file according to the invention.
• the root canal file according to the invention shown in figs. 3-8 is produced by grinding of two grooves 4, 6 which extend helically along a tapered file blank, see fig. 3 and 4.
• the grooves are displaced in relation to each other in the longitudinal direction of the file blank,so that each helix turn of one of the grooves is situated between two helix turns following after each other of the other groove and so that the entrances of the grooves at the tip of the working part are positioned at diametrically opposite points, i.e. displaced 180 in relation to each other.
• the grooves are so designed that they form two continous, helical edges 8,10, see figs. 3, 4 and 7.
• these cutting edge helices are displaced in relation to each other along the longitudinal direction of the file so that each turn in one of the cutting edge helices is situated between two turns following after each other of the other cutting edge helix.
• the pitch of the cutting edge helices 8,10 of the file according to the invention (and also the pitch of the helical grooves 4,6 between the cuttin edges) is twice as large as the pitch of the only helix of the H-file, cf. figs. 2 and 4.
• the file according to the invention in this way can be designed with a comparatively large pitch of the grooves and the cutting edges respectivel it becomes pliable and flexible and can easily be moved down into curved root canals with no risk of being broken or cracked.
• the large pitch material which is cut away in the root canal is effectively transported out of the canal by turning the file. Consequently the file gets a large capacity of removing material.
• the working part of the root canal file according to the invention is in general cone-shaped.
• fig. 8 the working part of a file according to th'e invention is schematically shown.
• generatrices 18,20 of the cone are schematically shown.
• the cutting angle ⁇ can be varied by making the grooves between the cutting edges deeper or more shallow, i.e. the file is formed with a bigger or smaller core, the angle being largerfor a file having bigger core thanfor a file having smaller core. Consequently, the angle ⁇ can be varied by changing the depth of the groove in the file.
• the file according to the invention comprises two helical cutting edges which are manufactured by grinding two helical grooves, displaced 180 in relation to each other, at each level along the longitudinal direction the file has two operating cutting - edges situated opposite to each other which minimizes the risk of breaking the file when it is used.
• the file can be formed with much thinner core and yet resists the stresseswhen it is used.
• the thin core of the file together with the large pitch of its cutting edges, or grooves between the cutting edges, make the 'file pliant and flexible, so that it without difficulty can be moved down also into curved root canals.
• the deep grooves between the cutting edges (i.e. the thin core) in combination with the large pitch of the grooves also result in a large capac of the file of effectively removing out of the root canal material which has been cut away by rotating the file.

Landscapes

• Health & Medical Sciences (AREA)
• Engineering & Computer Science (AREA)
• Biomedical Technology (AREA)
• Neurology (AREA)
• Neurosurgery (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• Surgery (AREA)
• Oral & Maxillofacial Surgery (AREA)
• Dentistry (AREA)
• Epidemiology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Dental Tools And Instruments Or Auxiliary Dental Instruments (AREA)
• Milling, Broaching, Filing, Reaming, And Others (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20333111

Family Applications (1)

Country Status (6)

Cited By (5)

Families Citing this family (5)

Citations (8)

• 1977
  • 1977-12-05 SE SE7713787A patent/SE416518B/sv unknown
• 1978
  • 1978-11-29 CH CH721479A patent/CH623224A5/de not_active IP Right Cessation
  • 1978-11-29 GB GB7942982A patent/GB2035806B/en not_active Expired
  • 1978-11-29 WO PCT/SE1978/000086 patent/WO1979000344A1/en unknown
  • 1978-11-29 JP JP54500122A patent/JPS5816893B2/ja not_active Expired
• 1979
  • 1979-07-03 EP EP78900300A patent/EP0006956A1/en not_active Ceased

Patent Citations (8)

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