WO2022208148A1

WO2022208148A1 - Endodontic instrument including a plastic and metal tool

Info

Publication number: WO2022208148A1
Application number: PCT/IB2021/055900
Authority: WO
Inventors: Gianluca PLOTINO; Eugenio Pedulla'
Original assignee: Lg Innovation S.R.L.
Priority date: 2021-03-29
Filing date: 2021-07-01
Publication date: 2022-10-06

Abstract

A tool (1) for an endodontic instrument (100), comprises: a body (2), elongated along a longitudinal axis (A) between a first end (2A), connectable to the endodontic instrument (100), and a second end (2B), opposite the first end (2A); a cutting element (3), comprising a maintaining portion (PM), connected to the body (2), and a cutting portion (PT), protruding from the body (2) in a radial direction (R), perpendicular to the longitudinal axis (A) of the body (2), the cutting element (3) extending along the longitudinal axis (A) of the body (2) between a first end (3A), proximal to the first end (2A) of the body (2), and a second end (3B), longitudinally spaced from the first end (3A). The cutting element (3) is made of a metallic material and the body (2) includes a matrix made of plastic material. The maintaining portion (PM) of the cutting element (3) is embedded in the matrix.

Description

ENDODONTIC INSTRUMENT INCLUDING A PLASTIC AND METAL

TOOL

Technical field

This invention relates to a tool, an endodontic instrument for cleaning a dental cavity and a method for making the tool. Background art

In the sector of endodontic instruments, the use is known of instruments for cleaning dental cavities including a tool. In the prior art solutions, the instrument comprises the use of a tool made of metal material. The tool comprises a propeller designed to come into contact with the dental cavity for cleaning the walls of the dental cavity. Moreover, the propeller of the instrument, by rotating, allows removal of the detritus which is created in the cleaning, operating as a screw feeder.

Said solutions, however, are subject to micro-fractures and fractures of the tool which, besides reducing the efficiency of the tool, may produce metal debris or an entire portion of the instrument that might remain in the dental cavity.

Other solutions comprise using tools with plastic matrix materials in which metal nanoparticles are embedded. An example of these instruments is described in patent document EP1377230B1. These solutions, however, have very low cutting capacity and are not sufficiently effective.

Aim of the invention

The aim of the invention is to provide a tool, an endodontic instrument and a method for making the tool which overcome the above-mentioned drawbacks of the prior art.

Said aim is fully achieved by the tool, the endodontic instrument and the method according to the invention as characterised in the appended claims.

According to an aspect of the invention, the invention provides a tool for an endodontic instrument.

The tool comprises a body. The body is elongate along a longitudinal axis between a first end, connectable to the endodontic instrument (that is, to a motor of the endodontic instrument), and a second end, opposite the first end.

The tool comprises a cutting element. The cutting element comprises a maintaining portion, connected to the body. The cutting element comprises a cutting portion, protruding from said body in a radial direction, perpendicular to the longitudinal axis of the body.

The cutting element extends along the longitudinal axis of the body between a first end, proximal to the first end of the body, and a second end, longitudinally spaced from the first end. Preferably, the cutting element is made of a metallic material. Moreover, the body includes a matrix made of plastic material.

Advantageously, the maintaining portion of the cutting element is embedded in the matrix.

The presence of the plastic matrix allows a flexibility of the tool, reducing the fractures and the micro-fractures. The presence of the cutting element, in particular of the cutting portion, allows a high level of cutting and cleaning efficiency. For this reason, the tool is effective and not very subject to failure.

According to an embodiment, the cutting element is a helical blade, having an extension along the longitudinal axis. As well as having the capacity to advance in the dental cavity, the helical blade also performs the function of removing detritus from the dental cavity.

Preferably, the blade has a cone or truncated cone cross section, converging in the direction coming out of the longitudinal axis. This feature makes it possible to obtain a connection point between the blade and the body which is thicker and thus more resistant to bending stresses, thus further reducing the possibility of failure of the blade. According to an embodiment, the maintaining portion comprises one or more slots. Said one or more slots are filled by the plastic material of the matrix of the body.

This guarantees that the blade does not slide off the plastic matrix, since the slots make contact with the plastic material.

The body comprises a connecting surface, at the first end of the body. The body comprises a lateral surface, on which the cutting tool is embedded. The body comprises a tip surface, at the second end of the body.

According to an embodiment, advantageously, the tool comprises a pumping hole. The pumping hole includes an inlet opening, preferably made on the connection surface, to connect the pumping hole to a pump of the endodontic instrument. The pumping hole comprises a dispensing opening, made on the lateral surface, for dispensing a fluid.

According to this embodiment, the dental cavity is also cleaned through a flow of washing fluid which facilitates removal of detritus.

According to an embodiment, the pumping of washing fluid may be continuous or intermittent.

According to an embodiment, the pumping hole comprises an additional dispensing opening, to form a plurality of dispensing openings.

Preferably, at least two dispensing openings of said plurality of dispensing openings are spaced along the longitudinal axis. Moreover, at least two dispensing openings of said plurality are angularly spaced relative to the longitudinal axis.

According to an embodiment, the cutting element is defined by a plurality of blades oriented longitudinally and angularly spaced from each other. Each blade extends along the longitudinal axis of the body between a respective first end, proximal to the first end of the body, and a respective second end, proximal to the second end of the body.

According to one aspect of this description, this invention provides an endodontic instrument for cleaning a dental cavity. The instrument comprises a container, including a connector. The instrument comprises an actuator, located inside the container.

The instrument comprises a tool, connected to the connector. The tool is connected to the actuator for being moved.

The tool is a tool which includes one or more of the features described in the invention.

Preferably, the endodontic instrument comprises a pump, designed to pump (continuously or intermittently) a washing fluid into the pumping hole of the tool.

According to an aspect of the invention, the invention provides a method for making a tool for an endodontic instrument.

The method comprises a step of preparing a cutting element made of metal, comprising a maintaining portion and a cutting portion.

The method comprises a step of preparing a body, elongate along a longitudinal axis between a first end, connectable to endodontic instrument, and a second end, opposite the first end. The body has a matrix made of plastic material, with the portion for maintaining the cutting element embedded in the matrix. In that way, the cutting element extends along the longitudinal axis of the body between a first end, proximal to the first end of the body, and a second end, longitudinally spaced from the first end.

Preferably, the body is made by injection co-moulding on the cutting element.

The step of moulding the body comprises a step of making a pumping hole including an inlet opening, designed to receive a washing fluid from the endodontic instrument, and a dispensing opening, from which the washing fluid can be dispensed towards a dental cavity.

Brief description of the drawings

These and other features will become more apparent from the following detailed description of a preferred embodiment, illustrated by way of non- limiting example in the accompanying drawings, in which:

- Figure 1 illustrates an endodontic instrument for cleaning a dental cavity;

- Figure 2 illustrates an embodiment of a tool of the instrument of Figure 1 ;

- Figure 3 illustrates a cross section of a detail of the tool of Figure 2;

- Figure 4 illustrates a cross section of a detail of a further embodiment of the tool of Figure 2;

- Figure 5 illustrates an enlargement of a detail of a cutting element of Figure 4;

- Figures 6 and 7 illustrate perspective views of a first embodiment and a second embodiment, respectively, of the tool of Figure 2.

Detailed description of preferred embodiments of the invention

With reference to the accompanying figures, the number 100 indicates an endodontic instrument for filling a dental cavity. The instrument 100 can be used both to perforate a tooth, in order to remove the dental material contained therein or to clean and scrape the walls of a tooth that is already perforated and in which the dental cavity has already been made.

The instrument 100 comprises a container 101 , defining an internal space VI. The container 101 comprises a handgrip to be handled by a user. It should be noted that, according to an embodiment, the container 101 is not inside the endodontic instrument, that is to say, it is an outer container 101 which, by means of a dedicated pump, circulates the fluid towards the tooth passing through a cavity made inside the instrument.

According to an embodiment, the connector is elongate along an axis of extension.

The instrument 100 comprises an actuator 102. The actuator 102 is preferably a rotary actuator. The actuator 102 is positioned inside the internal space VI. The rotary actuator 102 is connectable to a tool 1 to place it in rotation. The instrument 100 comprises a first button 102', connected to the actuator 102 and selectable for starting or interrupting the actuator on request. The button 102' is positioned on the outer surface of the container 101 so as to be accessible to the user.

The instrument 100 comprises a pump 103. The pump 103 is configured to pump a washing fluid into the dental cavity through the tool 1.

The pump 103 comprises an activating pushbutton 103', positioned on the outer surface of the container 101 for allowing a user to start or interrupt the pump on request.

The activating button 103' could also be a voice actuator (that is, a voice command or a Bluetooth command, connectable to a cordless pedal in such a way as to be able to activate and deactivate even simultaneously whilst a cutting tool is used, without necessarily having to use a hand for pressing a button).

Moreover, the pump 103 comprises a connector 103" to an external washing fluid supply. Alternatively or in addition, a tank may be present inside the container 101 which contains washing fluid. According to other embodiments, the instrument 100 comprises a plurality of tanks, each of which comprises a respective washing fluid.

The instrument 100 comprises a connection zone ZC, to which the tool 1 is connectable.

According to an aspect of the invention, the invention provides a tool 1.

The tool 1 comprises a body 2. The body 2 comprises a matrix made of plastic material. According to some embodiments, the matrix made of plastic material may be doped with metallic particles of various types, for example to increase the resistance to abrasion of the body 2.

The body 2 is an elongate body along a longitudinal axis A between a first end 2A and a second end 2B. According to an embodiment, the body 2 has a cone or truncated cone shape converging in the direction oriented from the first end 2A to the second end 2B.

According to an embodiment, the longitudinal axis A is parallel to the axis of extension of the container 101. According to other embodiments, the longitudinal axis A is inclined relative to the axis of extension of the container 101. The body 2 comprises a connecting surface 21 , oriented towards the connection zone ZC of the container 101.

According to an aspect of this invention, the tool 1 comprises a suction device, configured for sucking the fluid and/or the detritus, raising from the tool 1. More specifically, according to an embodiment, the suction device is a suction ring, positioned at the connection zone ZC and surrounding, at least partly or completely, the body 2 of the tool 1.

The body 2 comprises a tip surface 22, oriented in the opposite direction to the connecting surface 21. The body 2 comprises a lateral surface 23, joined to the tip surface 22 and to the connecting surface 21.

According to an embodiment, the body 2 comprises a shank 25. The shank 25 extends along the longitudinal axis A, starting from the first end 2A of the body 2 to an intermediate position 2C, interposed between the first end 2A and the second end 2B. According to an embodiment, the shank 25 has a cylindrical lateral surface.

The tool 1 comprises a cutting element 3. The cutting element 3 is configured to come into contact with the dental cavity and to be inserted into the dental root canals to remove and/or scrape the walls of the dental cavity.

The cutting element 3 comprises a maintaining portion 3A, connected to the body 2. Preferably, the maintaining portion 3A is embedded in the body 2. In other words, the maintaining portion 3A is surrounded by the plastic matrix of the body 2.

The cutting element 3 comprises a cutting portion 3B. The cutting portion 3B protrudes from the body 2 in a direction coming out of the longitudinal axis A.

The maintaining portion 3A and the cutting portion 3B are formed as a single piece and are not two separate parts. They are identified by the fact that one (maintaining portion 3A) is inside the matrix, whilst the other (cutting portion 3B) is outside the plastic matrix.

The maintaining portion 3A has a radial extension which is 20% greater than the total radial extension of the cutting element 3. Preferably, the maintaining portion 3A has a radial extension of between 30% and 60% of the total radial extension of the cutting element 3.

According to an embodiment, the cutting element 3 is a helical blade which extends along the longitudinal direction A between a first end 3A and a second end 3B. The first end 3A is close to the first end 2A of the body 2 (and is therefore close to the container 101 of the instrument 100). According to an embodiment, the body 2 and the helical blade 3 define a continuous spiral which extends from the first end 2A of the body to the second end 2B of the body.

More specifically, the profile of the helical blade 3 on a radial cutting plane is a cone or truncated cone, converging in the direction coming out from the longitudinal axis A.

According to an embodiment, the cutting element 3 is defined by a plurality of blades 31 spaced at angular intervals from each other. More specifically, according to an embodiment, each blade 31 extends along the longitudinal axis A between a first end 31 A, proximal to the first end of the body 2A, and a second end 31 B, proximal to the second end of the body 2B.

Said blades are substantially parallel to the lateral surface 23 of the body 2. Each blade 31 comprises a respective maintaining portion PM and a respective cutting portion PT.

According to an embodiment, said plurality of blades 31 is a plurality of helical blades, which are spaced from each other along the longitudinal axis A and/or angularly relative to the longitudinal axis A.

It should be noted that, according to an embodiment, the cutting element 3 extends, along the longitudinal axis A, from the intermediate position 2C of the body 2 to the second end 2B of the body 2. For this reason, the shank 25 does not have the cutting element 3, which is positioned only on the end part (proximal to the tooth) of the body 2.

According to an embodiment, the cutting element 3 comprises one or more slots 32. Said one or more slots are made in the maintaining portion PM of the cutting element 3. Said one or more slots 32 preferably pass through the cutting element 3 in such a way as to allow the plastic matrix to flow through and fill it.

According to an embodiment, the tool 1 comprises a handle 5. The handle 5 is positioned, along the longitudinal axis A, upstream of the first end 2A of the body. In short, the handle 5 is connected to the first end 2A of the body 2. The handle 5 is configured for connecting to the connection zone ZC of the instrument 100.

According to an embodiment, the tool 1 comprises a pumping hole 4, which extends along the longitudinal axis A between an inlet opening 41 and a dispensing opening 42. The inlet opening 41 is made on the connecting surface 21 and is configured to receive the washing fluid from the pump 103 of the instrument 100. The dispensing opening 42 is preferably made in the lateral surface 23 of the body 2. According to an embodiment, the dispensing opening 42 is positioned between two successive propellers of the helical blade.

According to an embodiment, the dispensing opening 42 is positioned in the space between two blades 31.

According to an embodiment, there is a plurality of dispensing openings 42, for example each located between a space between two blades 31 or each positioned in the space between two successive propellers of the helical blade.

According to an embodiment, there are two or more dispensing openings 42 between two propellers of the helical blade. In that case, they are angularly spaced from each other, preferably in a homogeneous manner. Moreover, according to some embodiments, there are two or more dispensing openings 42 between two blades 31. In that case, they are longitudinally spaced, preferably in a homogeneous manner along the longitudinal length of the body.

According to an aspect of the invention, the body 2 comprises a cutting side and a washing side. The cutting side is configured to house the cutting element 3 (which may have the shape of a spiral elongate along the longitudinal direction or a rectilinear shape along the longitudinal direction). The washing side is free of the cutting element 3 and includes said dispensing opening 42, to allow the pumping of the washing fluid. Preferably, the cutting side and the washing side are offset by 180A from each other along the longitudinal axis A, each extending angularly for 180A. According to other embodiments, the cutting side has an angular extension between 180A and 270A, whilst the washing side has an angular extension between 180A and 90A.

In this way, the tool 1 , rotating, allows an alternating of the washing and cutting which considerably increases the efficiency of the instrument.

Claims

1. A tool (1 ) for an endodontic instrument (100), comprising:

- a body (2), elongated along a longitudinal axis (A) between a first end (2A), connectable to the endodontic instrument (100), and a second end (2B), opposite the first end (2A);

- a cutting element (3), comprising a maintaining portion (PM), connected to the body (2), and a cutting portion (PT), protruding from said body (2) in a radial direction (R), perpendicular to the longitudinal axis (A) of the body (2), the cutting element (3) extending along the longitudinal axis (A) of the body (2) between a first end (3A), proximal to the first end (2A) of the body (2), and a second end (3B), longitudinally spaced from the first end (3A), wherein the cutting element (3) is made of a metal material and the body (2) includes a matrix made of plastic material, the maintaining portion (PM) of the cutting element (3) being embedded in the matrix.

2. The tool (1) according to claim 1 , wherein the cutting element (3) is a helical blade, having an extension along the longitudinal axis (A).

3. The tool (1) according to claim 2, wherein the helical blade has a cone or truncated cone shaped section, converging in the direction coming out from the longitudinal axis (A).

4. The tool (1) according to any one of the preceding claims, wherein the maintaining portion (PM) comprises one or more slots (32), and wherein said one or more slots (32) are filled by the plastic material of the matrix of the body (2).

5. The tool (1) according to any one of the preceding claims, wherein the body (2) comprises a connecting surface (21), at the first end (2A) of the body (2), a lateral surface (23), on which the cutting element (3) is embedded, and a tip surface (22), at the second end (2B) of the body (2), and wherein the tool (1) comprises a pumping hole (4), including an inlet opening (41), made on the connecting surface (21), for connecting the pumping hole (4) to a pump (103) of the endodontic instrument (100), and a dispensing hole (42), made on the lateral surface (23), for dispensing a fluid.

6. The tool (1) according to claim 5, wherein the pumping hole (4) comprises an additional dispensing opening, to form a plurality of dispensing openings.

7. The tool (1) according to claim 6, wherein at least two dispensing openings of said plurality of dispensing openings are spaced along the longitudinal axis (A).

8. The tool (1) according to any one of the preceding claims, wherein the cutting element (3) is defined by a plurality of blades (31) oriented longitudinally, angularly spaced from each other, each blade (31) extending along the longitudinal axis (A) of the body (2) between a respective first end (31 A) proximal to the first end (2A) of the body (2), and a respective second end (31 B), proximal to the second end (2B) of the body (2).

9. An endodontic instrument (100) for cleaning a dental cavity, comprising:

- a container (101), including a connector (ZC);

- an actuator (102), positioned inside the container (101);

- a tool (1), connected to the connector (ZC) and to the actuator (102) for being moved, wherein the tool (1 ) is a tool according to any one of the preceding claims.

10. The endodontic instrument (100) according to claim 9, comprising a pump (103), configured to pump a washing fluid into the pumping hole (4) of the tool (1).

11. An endodontic instrument (100) according to any one of the preceding claims, wherein the body (2) comprises a cutting side, on which the cutting element (3) is positioned, and a washing side, including at least one dispensing opening, through which a washing fluid is dispensed, and wherein the washing side and the cutting side are angularly spaced relative to the longitudinal axis (A).

12. The endodontic instrument (100) according to any one of the preceding claims, comprising a suction tool, configured to suck a washing fluid from a dental cavity in which the instrument (100) is operating, and wherein the suction tool is a suction ring.

13. The endodontic instrument (100) according to any one of the preceding claims, wherein the cutting element (3) is defined by a plurality of helical blades, which are separate from each other and spaced along the longitudinal axis (A).

14. A method for making a tool (1) for an endodontic instrument (100), comprising the following steps:

- preparing a cutting element (3) made of metal, comprising a maintaining portion (PM) and a cutting portion (PT);

- making a body (2), elongated along a longitudinal axis (A) between a first end (2A), connectable to the endodontic instrument (100), and a second end (2B), opposite the first end (2A), the body (2) having a matrix of plastic material, with the maintaining portion (PM) of the cutting element (3) embedded in the matrix, so that the cutting element (3) extends along the longitudinal axis (A) of the body (2) between a first end (3A), proximal to the first end (2A) of the body (2), and a second end (3B), spaced longitudinally from the first end (3A).

15. The method according to claim 14, wherein the body (2) is made by injection co-moulding on the cutting element (3).

16. The method according to claim 14 or 15, wherein the step of moulding the body (2) comprises a step of making a pumping hole (4) including an inlet opening (41), designed to receive a washing fluid from the endodontic instrument (100), and a dispensing opening (42), from which the washing fluid can be dispensed towards a dental cavity.