This application claims priority to U.S. patent application Ser. No. 29/445,322 for Hybrid Rotary File, filed Feb. 11, 2013.
All prior art endodontic file systems consist of either a landed rotary file or a non-landed rotary file. Landed rotary files are considered safer but less efficient than non-landed rotary files. Non-landed rotary files are considered more efficient but also more susceptible to procedural mishaps.
The radial lands of a landed rotary file keep the file centered in the root canal and help the file follow the natural canal anatomy. Therefore, when the file passes through the apical foramen of the canal, the file does not transport or destroy the natural apical anatomy. However, the file is less efficient at cutting because the radial lands prepare the canal in a planing motion. The landed file also has less flexibility leading to increased risk of file separation resulting in pre-mature loss of the tooth.
A non-landed file, while cutting more efficiently and having greater flexibility than a landed file, does not naturally stay centered in the root canal. Therefore, it can transport or straighten curved root canals. Further, when non-landed files of medium to large size (i.e., size 20 mm or greater) pass through the apical foramen of the canal, the files can transport the natural position of the apical foramen and rip the apical foramen. This transportation and ripping of the apical foramen leads to difficulty in filling the root canal and can lead to overfilling the root canal resulting in pre-mature tooth loss.
An endodontic system made according to this invention includes a set of at least three endodontic files, the first file of the set being entirely non-landed and tapered and having a diameter at its tip end which is smaller in diameter than that of a second and a third file of the set at their respective tip end, and the second and third files each having the following characteristics:
The active length of the second is at least one of a different diameter at the tip end and a different taper than the third file. Preferably, the second and third files each have a diameter of at least 0.20 mm at the tip end and a taper of at least 4% along the active length. Beginning no sooner than 3 mm from the tip end, each file transitions from the landed portion to the non-landed portion.
An endodontic file made according to this invention has the same characteristics as the second and third file of the set.
An endodontic system made according to this invention includes at least two different types of endodontic files. The first type of file is a non-landed file 20. The second type of file is a “hybrid” file 30, having radial lands in the apical third 43 of the active length 41 of the file 30 and being non-landed in the middle third 47 and coronal third 49, which form the cutting length 45.
Table 1 lists the preferred dimensions of the files 20 and 30 used in the system, with each hybrid file 30 preferably being 25 mm in overall length under the shank. The non-landed files 20 are of a kind well-known in the art. Preferably, there are two non-landed files 20 in the system 10, with each file 20 being less than 0.20 mm in diameter at its tip end and having less than a 6% taper.
The hybrid files 30 each include a tapered active length 41 and a non-tapered non-active length 51, the two lengths 41, 51 making up the overall machined length 31 of the file 30 (e.g. a 25 mm file 30 having a 16 mm machined length 31 of which 10 mm is the active length 41 and 6 mm is the non-active length 51). The apical third 43 of each file 30 is landed and extends to at least 3 mm from the tip end 39 of the file 30, depending on the active length 41. The cross section of apical third 43 is preferably formed by three flutes 35 with landed cutting surfaces or radial lands 37 in between (see
The file 30 transitions between the radial lands 37 in the apical third 43 to no radial lands in the middle third 47 (see e.g.
Preferably, there are four hybrid files 30 in the system having a minimum diameter at the tip end of no less than 20 mm and a tapered active length 41 of at least 4%, with each file 30 having a non-tapered non-active length 51. In one preferred embodiment, the four files 30 are sized 20-06%, 25-04%, 30-06%, and 40-06% respectively. The pitch of each file 30 preferably increases along the active length 41 toward the non-active length 51.
Each hybrid file 30 combines the efficiency of a non-landed file with the safety of a landed file to provide a clinician with an efficient and safe file. The landed portion 43 of the file 30 helps the file 30 remain centered in the canal to maintain the original canal anatomy yet keeps the file 30 flexible due to the transition to a non-landed file in the middle third 47 and coronal third 49. When one or more files 30 are used in combination with non-landed files 20, the clinician has what he or she needs to successfully shape a patient's root canal without fear of file separation, strip perforation, transporting the canal or damaging the canal's apical foramen.
While the preferred embodiments have been described in detail, the invention is defined by the following claims, including those claims' full range of equivalency.
Number | Name | Date | Kind |
---|---|---|---|
4859183 | Martin | Aug 1989 | A |
5092769 | Reiter et al. | Mar 1992 | A |
5464362 | Heath | Nov 1995 | A |
5775902 | Matsutani et al. | Jul 1998 | A |
5836764 | Buchanan | Nov 1998 | A |
6174165 | Katsuumi | Jan 2001 | B1 |
7300281 | Cantatore et al. | Nov 2007 | B2 |
7513722 | Greenberg et al. | Apr 2009 | B2 |
7766657 | Jaunberzins | Aug 2010 | B2 |
8047842 | Johnson | Nov 2011 | B2 |
8137101 | Fujii et al. | Mar 2012 | B2 |
8496476 | Scianamblo | Jul 2013 | B2 |
20100119990 | Lampert | May 2010 | A1 |
20130240092 | Gao et al. | Sep 2013 | A1 |
20130273497 | Scianamblo | Oct 2013 | A1 |
Entry |
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Rotary endodontic file for root canal desobturation PROTAPER® Universal Dentspl Y Maille Fer. Medical Expo. [Retrieved on Dec. 20, 2013]. Retrieved from the Internet: <URL:http://www.medicalexpo.com/prod/dentsply-maillefer/rotaryendodontic-files-root -canal-desobturation -72098 . . . >. |
Number | Date | Country | |
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Parent | 29445322 | Feb 2013 | US |
Child | 14341964 | US |