A dental treatment instrument, particularly for reaming root canals

Abstract

The present invention relates to a gum treatment instrument comprising a working segment (11) having a working cross-section (110) and terminating in a distal portion (12) having guiding and cutting capabilities. The distal portion comprises a rounded guiding head (13) and an angled cutting segment (14). The angled cutting segment comprises a distal zone (16) adjacent to the guiding head and a proximal zone (17) between the distal zone and the working segment. The angled cutting segment (14) further comprises a cutting edge (15) extending the entire length of the proximal and distal zones. The distal zone comprises a distal cross-section (160) with a constant contour, and the proximal zone comprises a proximal cross-section (170) whose contour changes between the distal cross-section and the working cross-section (110).

Description

Technical Field

[0001] The present invention relates to a gingival treatment instrument for reaming the root canal of a patient's tooth. The instrument has a working extension terminated by an end zone with a free end of a tip shape. This end zone has a dual function of guiding and cutting.

Background Art

[0002] The cleaning and shaping of the root canal of a tooth, which is intended to receive a filling, is carried out using a reaming instrument having an active part called a working extension. The function of the reaming instrument is to form, adjust, and clean the inner wall of the root canal to prevent any accumulation of oxygen in the root canal, which is likely to promote the growth of bacteria in the tooth, and to prepare for treatment and the reception of a filling.

[0003] However, it is essential for the operator to have an instrument capable of tracking the root canal in order to treat the wall without deviating from the direction of the root canal regardless of its configuration. Currently, tracking the root canal is mainly related to the guiding characteristics of the end zone, and more specifically, to the outer shape of the tip. Nevertheless, even if this guidance is an essential function, machining the wall of the root canal is also an essential function, and for this purpose, the end zone, especially the tip, must be perfectly configured so that it can effectively fulfill the two functions of guiding and cutting. Next, the removal of substances is carried out by the working extension of the instrument. The working extension of the instrument extends the end zone. The end zone has a cutting function, that is, a function of machining the wall of the root canal, and a function of discharging the substances removed by the machining, as is known.

[0004] In fact, root canal preparation is carried out using a series of instruments, all of which have guiding properties in the end zone and the property of discharging the removed material by cutting in the next working zone. Generally, the operator begins root canal preparation using an instrument with a nominal diameter adapted to the initial diameter in the tooth root canal. Next, the operator replaces the first instrument with the same type of instrument with a larger nominal diameter and similarly continues to gradually increase the cross-section of the instrument.

[0005] Many of the existing instruments have a guiding tip without a cutting function, so a series of six consecutive instruments for the operator that gradually increase at a pitch of 0.05 mm is essential when changing, for example, from an initial diameter of 0.10 mm to 0.40 mm. If this process is not monitored, the risk of instrument breakage within the root canal increases considerably.

[0006] However, there are active tip instruments that enable penetration into so-called very small-sized root canals, which have a cutting effect at the center. However, according to the usage guidelines, these instruments are limited to retreatment work and are used only for the straight part of the root canal. Using them in the curved part of the root canal will inadvertently cause perforation of the root canal wall.

[0007] Swiss Patent Invention No. 707745 by the present inventor describes a gingival treatment instrument having a working extension terminated by an end zone with a tip-shaped end. FIGS. 1(a) and 1(b) respectively show a longitudinal sectional view and a cross-sectional view of the end zone 12. The end zone 12, on the one hand, comprises a tapered guiding segment 13 terminating at the tip. This guiding segment 13 has a tip angle of 10 - 60°. On the other hand, the end zone 12 comprises a cornered cutting segment 14 adjacent to the tapered guiding segment 13. The cutting segment 14 comprises several cutting edges 15 that form an angle with the longitudinal central axis of the instrument. This cornered cutting segment 14 extends over a specific length and is located in the middle between the tapered guiding segment 13 and the working extension 11. This cornered cutting segment 14 has a cross-section that progressively increases towards the working extension 11 of the instrument 10 over at least a part of its length from the base of the tapered guiding segment 13. There are three cutting edges 15 evenly arranged around the periphery of the instrument 10. The tip 16 of the instrument is soft with a rounded outer shape, enabling the assumption of a guiding function that allows the instrument to follow the line of the root canal regardless of the shape of the root canal, especially its curvature.

[0008] The penetration of the instrument 10 described in Swiss Patent Invention No. 707745 is schematically represented in a straight root canal 30 in FIG. 2 and in a curved root canal 30 in FIG. 3. In a straight root canal, the instrument is selected such that its optimal cutting diameter D3 corresponds to the initial diameter of the root canal. The processing of the root canal 30 can be effectively carried out, and the expansion of this root canal is gradually made until it reaches the nominal diameter of the instrument 10. Due to the outer shape in the tapered guiding segment 13 of the instrument 10, the tapered guiding segment 13 follows the curvature of the root canal 30 without the risk of drilling a hole in the wall and opening a second root canal in the tooth.

[0009] The cutting function at the tip enables the reduction of the number of instruments required for advancement and for cleaning the root canal up to the apex.

Prior Art Documents

Patent Document

[0010]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0011] Basically, the present invention aims to create an instrument that addresses these two complementary requirements: namely, to reliably guide the instrument to penetrate into the root canal and to simultaneously perform cutting on the wall while, on the one hand, observing the configuration, that is, to follow the curvature of the root canal.

Means for Solving the Problems

[0012] This goal is achieved by an instrument for gingival treatment for reaming the root canal. This instrument comprises a working extension having a working cross-section, and this working extension is terminated by a distal portion having a dual function of guidance and cutting. This distal portion comprises a guiding head and a bevelled cutting segment between this guiding head and the working extension. The bevelled cutting segment comprises a distal zone adjacent to the guiding head and a proximal zone between this distal zone and the working extension. This bevelled cutting segment further comprises a cutting edge extending over the entire length of the proximal zone and the distal zone. The distal zone comprises a distal cross-section of a certain shape, and the proximal zone comprises a proximal cross-section whose shape varies between the distal cross-section and the working cross-section.

[0013] The advantage of the gingival treatment instrument described here is the greater cutting efficiency of the instrument. The distal portion, through its cutting function and proximity to the guiding head, makes it possible to reduce the number of instruments required for advancement and for cleaning the root canal up to the apex. The number of instruments reduced is more than that of the instrument described in Swiss Patent Invention No. 707745 Specification.

[0014] When the gingival treatment base is in the working extension, i.e., when the guiding head is at the top of the root canal, cleaning the top zone of the root canal is usually very difficult, but it is made possible by the presence of the cutting edges of the angled cutting segments close to the guiding head. Better cleaning in the top zone of the root canal makes it possible to reduce the risk of subsequent reinfection of the root canal (which leads to treatment failure). This is because this zone is particularly susceptible to the influence of bacterial growth. Better machining of the top of the root canal by the angled cutting segments in the distal part facilitates subsequent steps of root canal treatment, such as sterilization and root canal filling in particular. Specifically, better machining of the top of the root canal enables ideal adjustment of the gutta-percha points when filling the "single cone" type.

[0015] Examples for implementing the present invention are shown in the description illustrated by the accompanying drawings.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6a

Figure 6b

Figure 7

Figure 8

DETAILED DESCRIPTION OF THE INVENTION

[0017] FIG. 4 shows a gingival treatment instrument 10 intended to ream the root canal of a patient's tooth. The instrument includes a working extension 11 having a working cross-section 110. The working extension 11 terminates at a distal portion 12 having a dual function of guiding and cutting. FIG. 5 shows details of the distal portion 12. The distal portion 12 includes an induction head 13 and a bevelled cutting segment 14 between the induction head 13 and the working extension 11. The bevelled cutting segment 14 includes a cutting edge 15 that forms an angle with the longitudinal axis 20 of the instrument 10. The bevelled cutting segment 14 includes a distal zone 16 adjacent to the induction head 13 and a proximal zone 17 between the distal zone 16 and the working extension 11. Note that the cutting edge 15 extends over the entire length of the proximal zone 17 and over the entire length of the distal zone 16 to the intersection of the induction head 13 and the distal zone 16 and is indicated by the surface 161 in FIG. 5.

[0018] FIGS. 6a and 6b show cross-sections A-A, B-B, C-C, D-D, E-E, F-F, and G-G of the distal portion 12 along the longitudinal axis 20 of the instrument at various positions (FIG. 6a) of the induction head 13 working towards the working extension 11. As illustrated in FIG. 6b, the distal zone 16 includes a distal cross-section 160 with a hexagonal outer shape forming six cutting edges 15 (cross-sections A-A, B-B). The proximal zone 17 includes a proximal cross-section 170. Its outer shape varies between the hexagonal cross-section 160 of the distal zone 16 and the working cross-section 110 (cross-sections C-C, D-D, E-E, F-F, and G-G).

[0019] The hexagonal outer shape of the distal cross-section 160 and the distribution of the cutting portions over the six cutting edges 15 ensure an optimal distribution of mechanical stress and minimize the risk of damaging the instrument.

[0020] For using this type of instrument, the following quantities are extremely important. The nominal diameters D1 and D2 are the diameters of the circumscribed circles, that is, the diameters of the circles in which the cross-section of the instrument in the working extension part 11 (see Fig. 4) is inscribed. The induction head diameter D3 is the diameter of the proximal base 130 of the induction head, that is, the diameter at the surface 161.

[0021] According to one embodiment, the diameter of the distal cross-section 160 in the distal zone 16 is constant. In other words, the circumscribed circle (the circle in which the cross-section of the distal zone 16 is inscribed) has a constant diameter. Fig. 6a shows such an example of the distal part 12, the distal zone 16 of which extends between cross-sections A-A and B-B and has a distal cross-section 160 of constant dimensions.

[0022] Fig. 7 shows a cross-section of the distal part 12 along the longitudinal axis 20 of the instrument. According to Fig. 8, the diameter D 17 of the proximal zone 17 increases progressively over at least a part of the length L 17 while going from the distal zone 16 towards the working extension part 11 of the instrument 10. The diameter D 16 of the proximal zone 16 also increases progressively over at least a part of the length L 16 between the induction head 13 and the proximal zone 17. In other words, at least a part of the distal zone 16 and the proximal zone 17 are tapered, forming a distal angle α 16 and a proximal angle α 17 with the longitudinal axis 20 of the instrument respectively.

[0023] According to another embodiment, the distal cross-section 160 of the distal zone 16 and the proximal cross-section 170 of the proximal zone 17 increase progressively over at least a part of the length of the proximal zone 17 and at least a part of the length of the distal zone 16 while going from the induction head 13 towards the working extension part 11 of the instrument 10.

[0024] In one embodiment, the induction head 13 is rounded. As illustrated in Figs. 5, 6a, and 7, the induction head 13 is substantially hemispherical (or dome-shaped).

[0025] In yet another embodiment, illustrated in FIG. 8, the diameter D3 of the induction head 13 is greater than the diameter D of the circumcircle of the distal zone 16 over at least a portion of the length of the distal zone 16. 16 According to one implementation, the diameter D3 of the induction head 13 is greater than the diameter D of the circumscribing surface of the distal zone 16 at the surface 161. 16 Greater.

[0026] Referring again to FIG. 6b (cross-sections A-A, B-B), the distal cross-section 160 has a substantially regular hexagonal shape. That is, its six sides all have substantially the same length. However, it is also possible to consider a distal cross-section 160 having an irregular hexagonal shape without departing from the scope of the invention.

[0027] The proximal cross-section 170 of the proximal zone 17 has a shape that gradually changes from the hexagonal outer shape of the distal cross-section 160 to a shape corresponding to the outer shape of the working cross-section 110 that works from the induction head 13 to the working extension 11.

[0028] For example, as illustrated in FIG. 6b (cross-sections B-B, C-C, D-D, E-E, F-F, and G-G), the working cross-section 110 is triangular (cross-section G-G), and the proximal cross-section 170 is transformed from a regular hexagonal outer shape (cross-section B-B) through irregular outer shapes (cross-sections C-C, D-D, and E-E) to a triangular outer shape (cross-sections F-F and G-G).

[0029] It goes without saying that the present invention is not limited to the described embodiments, and that various changes and simple modifications can be envisioned by those skilled in the art without departing from the scope of the invention.

[0030] For example, the working cross-section 110 can have a shape other than a triangle with three cutting edges. Similarly, the distal zone 16 can comprise a distal cross-section 160 having an outer shape different from the hexagonal outer shape illustrated in FIG. 6b. Specifically, at least the working cross-section 110 and / or the distal cross-section 160 can also have a more complex cross-section, such as an "S"-shaped cross-section with two cutting edges, a triangular cross-section with three cutting edges, a quadrilateral cross-section with four cutting edges, or a cross-section with more than four cutting cross-sections 15.

[0031] According to a preferred form of the invention, the length L of the induction head 13 G relative to the length L of the distal zone 16 16 of the ratio L 16 / L G is greater than 1. The ratio L 16 / L G can also be made greater than 2, greater than 3, or greater than 5. A high ratio of L 16 / L G means that the induction edge 15 of the distal zone 16 is suitable for the end of the angled cutting segment 14 and facilitates machining of the top of the root canal by the angled cutting segment 14.

[0032] The length L of the distal zone 16 16 relative to the length L of the proximal zone 17 17 The ratio can be expressed as a function of the distal angle α 16 , the proximal angle α 17 , the diameter D of the proximal zone 17 17 , and the diameter D of the distal zone 16 16 . More specifically, the ratio of the length L 16 to the length L 17 can be expressed by Equation 1.

[0033]

Equation

[0034] According to one embodiment, the length L of the distal zone 16 16The length L of the proximal zone 17 with respect to 17 is in the range of 0.1 to 10. The ratio of the length of the proximal zone 17 to the length of the distal zone 16 can be 0.2 to 4.5 or 0.6 to 1.8.

[0035] According to one embodiment, the diameter D of the circumscribed circle in the distal zone 16 16 is constant over the entire length L of the distal zone 16 16 . In other words, the distal angle (α 16 ) is substantially 0°.

[0036] Similarly, the diameter D of the circumscribed circle in the proximal zone 17 17 can be constant over the entire length L of the proximal zone 17 17 .

Explanation of symbols

[0037] 10 Instrument 11 Working extension 110 Working cross-section 12 Distal part, end zone 13 Induction head, induction segment 130 Proximal base 14 Angular cutting segment 15 Cutting edge 16 Distal zone, tip 160 Distal cross-section 161 Surface at the intersection of the induction head and the distal zone 17 Proximal zone 170 Proximal cross-section 20 Longitudinal axis 30 Root canal α 16 Distal angle α 17 Proximal angle D1, D2 Nominal diameter D3 Induction head diameter D 16 Diameter of the distal zone D 17 Diameter of the proximal zone L 16 Length of the distal zone L17 Length of the proximal zone L G Length of the induction head

Claims

1. A gingival treatment instrument for reaming the root canal of a patient's tooth, the instrument comprising a working extension having a working cross-section, the working extension terminating in a distal portion having a dual function of guiding and cutting, the distal portion comprising a rounded guiding head and a bevelled cutting segment between the guiding head and the working extension, the instrument comprising the bevelled cutting segment comprising a distal zone adjacent to the guiding head and a proximal zone between the distal zone and the working extension, the bevelled cutting segment further comprising a cutting edge extending over the entire length of the proximal zone and the distal zone, the distal zone having a distal cross-section of a constant cross-sectional shape, and the proximal zone having a proximal cross-section whose cross-sectional shape varies between the distal cross-section and the working cross-section, characterized in that it is a gingival treatment instrument, A gingival treatment instrument, wherein the diameter of the guiding head is larger than the diameter of the circumscribed circle of the distal zone over at least a part of the length of the distal zone.

2. The gingival treatment instrument according to claim 1, wherein the ratio of the length of the distal zone to the length of the guiding head is greater than 1 or greater than 2.

3. The gingival treatment instrument according to claim 1, wherein at least a part of the distal zone and the proximal zone are tapered, forming a distal angle and a proximal angle with the longitudinal axis of the instrument, respectively.

4. The gingival treatment instrument according to claim 1, wherein the diameter of the guiding head is larger than the diameter of the circumscribed circle of the distal zone at the intersection of the guiding head and the distal zone.

5. The gingival treatment instrument according to claim 1, wherein the ratio of the length of the proximal zone to the length of the distal zone is 0.1 to 10.

6. The ratio of the length of the proximal zone to the length of the distal zone is 0.2 to 4.5 or 0.6 to 1.8, the gingival treatment device according to claim 5.

7. The diameter of the circumscribed circle in the distal zone is constant over the entire length of the distal zone, the gingival treatment device according to claim 1.

8. The diameter of the circumscribed circle in the proximal zone is constant over the entire length of the proximal zone, the gingival treatment device according to claim 1.

9. The distal cross-section has a substantially regular hexagonal shape, the gingival treatment device according to claim 1.

10. The distal cross-section has an "S" shape with two cutting edges, a triangular shape with three cutting edges, or a square shape with four cutting edges, the gingival treatment device according to claim 1.

11. The working cross-section is triangular, the gingival treatment device according to claim 1.

12. The working cross-section has an "S" shape with two cutting edges, a triangular shape with three cutting edges, or a square shape with four cutting edges, the gingival treatment device according to claim 1.

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