System for endodontic treatment

Abstract

Provided is a system for endodontic treatment of a root canal. The system includes a handpiece containing a rotary motor adapted to rotate an endodontic file secured by the handpiece. A control unit executes a regime of motion of the motor to produce a regime of file motion in which episodes of oscillation of the file are separated by a rotation of the file. When the arc of a rotation is less than the arc of the oscillation that preceded the rotation, the arcs of the episodes of oscillation overlap and the formation of ridges in the root canal is avoided.

Claims

1. A system for endodontic treatment, comprising: (a) a handpiece containing a rotary motor adapted to rotate an endodontic file secured by the handpiece; (b) a processor configured to execute a regime of motion of the motor or produce a regime of file motion comprising: (c) for k=1 to n, where n is an integer; (i) oscillating the file through an arc α.sub.k at a frequency of oscillation f.sub.k for an amount of time T.sub.k or a number of oscillation cycles M.sub.k; and (ii) rotating the file either clockwise or counterclockwise through an arc β.sub.k.

2. The system according to claim 1, further comprising rotating the file in a continuous clockwise or counterclockwise rotation after completing one or more steps (c).

3. The system according to claim 1, wherein the β.sub.k is less than α.sub.k for at least one k.

4. The system according to claim 1, wherein α.sub.k is selected from the group consisting of 60°, 90°, 120°, 180°, and 360°.

5. The system according to claim 1, wherein the number of oscillation cycles M.sub.k is in the range of from 1 to 10.

6. The system according to claim 1, wherein an angular velocity of the file during an episode of oscillation is in the range of from 300°/sec to 2400°/sec.

7. The system according to claim 1, wherein any one or more of α.sub.k, f.sub.k, β.sub.k, T.sub.k, and M.sub.k, are predetermined constants for all k.

8. The system according to claim 1, wherein any one or more of α.sub.k, f.sub.k, β.sub.k, T.sub.k, and M.sub.k, are modulated.

9. The system according to claim 8, wherein modulation of any one or more of α.sub.k, f.sub.k, β.sub.k, T.sub.k, and M.sub.k, is predetermined.

10. The system according to claim 8, wherein modulation of any one or more of α.sub.k, f.sub.k, β.sub.k, T.sub.k, and M.sub.k, are modulated by a feedback mechanism comprising any one or more of a torque exerted on the file, depth of file penetration into a canal, file tip position relative to a canal apex, motor temperature, and elapsed time of treatment.

11. The system according to claim 8, wherein any one or more of α.sub.k, f.sub.k, β.sub.k, T.sub.k, and M.sub.k, are modulated randomly.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In order to understand the invention and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

(2) FIG. 1 shows a system of endodontic treatment in accordance with one embodiments of the invention;

(3) FIG. 2 shows a tooth root and root canal in which ledges have formed;

(4) FIG. 3 shows tooth roots having circular and flat root canals;

(5) FIG. 4 shows a regime of motion of an endodontic file in accordance with one embodiment of the invention; and

(6) FIG. 5 shows a regime of motion of an endodontic file in accordance with another embodiment of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

(7) FIG. 1 shows a system 2 for endodontic treatment in accordance with one embodiment of the invention. The system 2 comprises a handpiece 10 and a control unit 20. An endodontic file 11 is secured in a chuck of the handpiece head 12. The handpiece 10 further comprises an electric motor 14 fastened to a contra angle 13. The motor 14 is connected by a cable 15 to the control unit 20 which includes a microprocessor 19, a memory 21 a keyboard 16 and a display 17. The control system 20 controls the motor 14 in order to execute a predetermined or selectable regime of motion of the file 11, as explained below. In a cordless embodiment, the control unit is incorporated into the handpiece 10 and the system is battery operated. In another embodiment, the control unit is incorporated into the handpiece 10 and the system can alternate between being cordless or connected by a cable 15 to the host control/power source/charger unit.

(8) The memory 21 may be used to store operational parameters, such as speed, torque, operational sequences, etc. of an endodontic treatment; as well as a library of operational parameters for different files and/or file systems. The control unit 20 may include any one or more of a non-volatile memory, wired or wireless communication channels, an Internet channel, data storage media, etc.

(9) In accordance with the invention, the microprocessor 19 is configured to execute a phase controlled regime of motion. In one embodiment, the regime of motion comprises the following stages:

(10) (a) for k=1 to n, where n is an integer; (i) oscillating the file from an angular position θ.sub.k through an arc α.sub.k at a frequency of oscillation f.sub.k for an amount of time T.sub.k or a number of oscillation cycles M.sub.k; and (ii) rotating the file either clockwise or counterclockwise through an arc β.sub.k.

(11) FIG. 4 shows schematically an example of the regime of motions according to this embodiment for treating a root canal 50. The regime begins in FIG. 4a with an oscillation of the file in an arc α.sub.1=120°. At the termination of M.sub.1=10 oscillations, the file is rotated through an arc β.sub.1=60° and the file is then oscillated through an arc α.sub.2=120° at the new location (FIG. 4b) and after M.sub.2=10 oscillations rotated through an arc β.sub.2=60° (FIG. 4c). The process continues with oscillations of α.sub.3=120°, M.sub.3=5 (FIG. 4c); α.sub.4=120°, M.sub.4=5 (FIG. 4d); α.sub.5=120°, M.sub.5=3 (FIG. 4e) and α.sub.6=120°, M.sub.6=3 (FIG. 4d), interspersed with rotations β.sub.3=60°, β.sub.4=60°, and β.sub.5=60°, as indicated in FIG. 4. Since β.sub.k is less than α.sub.k for all k, the arcs of oscillations for different k overlap (six overlapping oscillations of 120° are used to completely cover the entire 360° circumference of the canal), and the formation of ledges is thus avoided. Most endodontic files have more than one cutting edge (usually 2 to 4) and the full coverage of the entire circumference of the canal can be achieved in fewer steps.

(12) Typically, the number of oscillation cycles M.sub.k is in the range of 1 to 10, and the angular velocity of the file during an oscillation stage is typically in the range of 300°/sec to 2400°/sec. β.sub.k may be less than, greater than, or equal to α.sub.k. Setting β.sub.k less than α.sub.k ensures overlap of the coverage of the canal wall during consecutive oscillation stages. α.sub.k may increase with increasing k. For example, as shown in FIG. 5, a regime may consist of several oscillation stages with α.sub.k=60°, M.sub.k=10 and β.sub.k=60° (FIG. 5a) followed by oscillation stages with α.sub.k=90°, M.sub.k=10 and β.sub.k=90° (FIG. 5b); then with α.sub.k=120°, M.sub.k=10 and β.sub.k=120° (FIG. 5c); α.sub.k=180°, M.sub.k=10 and β.sub.k=120° (FIG. 5d) and with α.sub.k=360°, M.sub.k=10 (FIG. 5e). The regime of motion may further comprise rotating the file in a continuous clockwise or counterclockwise rotation after completing the reciprocation stages.

(13) Any one or more of θ.sub.k, α.sub.k, f.sub.k, β.sub.k, T.sub.k and M.sub.k may be predetermined constants for all k. or any one or more of θ.sub.k, α.sub.k, f.sub.k, β.sub.k, T.sub.k and M.sub.k may be modulated. The modulation may be predetermined or random. The modulation may be determined during use by a feedback mechanism involving, for example, any one or more of a torque exerted on the file, depth of file penetration into a canal, file tip position relative to a canal apex, motor temperature, and elapsed time of treatment.

(14) As an example, in a preferred embodiment, when the torque applied to the file exceeds a predefined value, any one or more of the arcs, frequency or duration/number of oscillations can be modulated. For instance, the oscillation arc (α.sub.k) and/or the oscillation frequency can be reduced and/or the number of oscillations (M.sub.k) or the duration of oscillations (T.sub.k) can be increased. As another example, in preferred embodiment, when the file tip is advanced to a predetermined position relative to the apex, any one or more of the oscillation/reciprocation arcs, frequency or duration/number of cycles can be modulated, the motor may be stopped or reverse rotation can be activated, etc. For instance, when the file tip has reached the apical position, the oscillation/reciprocation frequency and the arcs may be reduced; audio feedback may be activated, etc.

(15) In another embodiment of the invention, the microprocessor 19 is configured to execute a regime of motion comprising the following stages: (i) rotating the file from an angular position θ.sub.k through an arc α.sub.k at a angular speed ω.sub.4; and (ii) rotating the file in an opposite direction through an arc β.sub.k wherein at least one of the sequences {α.sub.k, k=1 to n} and {β.sub.k, k=1 to n} includes at least two terms of different values.

(16) In a different embodiment the system may be combined with additional dental devices, such as apex locator, vitality tester, file identification system, file working length measurement system, file selection system, gutta-percha cutter, gutta-percha condenser, photo-polymerization lamp, trans-illumination lamp and others.