EP4633525A1

EP4633525A1 - Tool for endodontic treatment and related technique

Info

Publication number: EP4633525A1
Application number: EP23810142.2A
Authority: EP
Inventors: Marino Borrelli
Original assignee: Individual
Current assignee: Individual
Priority date: 2022-09-20
Filing date: 2023-09-20
Publication date: 2025-10-22
Also published as: WO2024062394A1; IT202200019290A1

Abstract

A tool for endodontic treatment comprises a handpiece (2) suitable of being grasped by a technician, a flexible tip (6) applied to said handpiece (2) to facilitate the heating and compaction of the thermoformable material, heating means for heating said flexible tip (6) controlled by an electronic driving circuit suitable for heating said flexible tip (6) from a minimum temperature to a maximum temperature by electrically powering said flexible tip (6) with a gradual temperature rise ramp provided with intervals of temperature stabilization, at least one compacting tool (10) for the thermoformable material.

Description

TOOL FOR ENDODONTIC TREATMENT AND RELATED TECHNIQUE Description

Technical Field

The present invention finds applications into the field of medical instruments, in particular in the dental field, and particularly has as its object a tool for carrying out endodontic treatments and the related technique of use.

State of the art

As known, the expression “endodontic treatment” refers to a medical treatment aimed at achieving patient comfort and healing of the compromised dental element.

One of the fundamental procedures involves filling the root canals, previously prepared, with a homogeneous and biocompatible material. Typically, the most commonly used material is gutta-percha, which is a natural, rubbery material obtained from certain species of trees, adequately purified and possibly mixed with other constituents, for example, zinc oxide, which give the material better properties during use.

Gutta-percha has the properties of passing, following the application of heat, from a solid to a plastic form, returning to its original solid form upon cooling.

The transformation of gutta-percha is divided into various phases, with a solid phase called beta phase and a transition phase into the plastic form of the material, called alpha phase, which occurs when the material reaches 42°.

Generally, the gutta-percha used in endodontics is packaged in cones whose size is proportionate to the size of the apex and which are designed to be inserted into the canal, to be subsequently heated and compacted. The compaction of the material is important not only to allow a better adaptation thereof, but also to compensate for changes in volume whose final outcome always corresponds to a certain degree of contraction.

Over the years, different root canal filling methods have been proposed, as well as different materials to achieve the intended object. Gutta-percha, in addition to the requirements of an ideal material, upon contact with heat changes from a solid, stable form to a fluid isomeric form and upon cooling returns to its original solid, stable form. The most commonly used techniques for filling dental cavities with gutta-percha involve applying small quantities of heated gutta-percha into the cavity with a hot probe and then compacting it within the cavity itself using a compactor. A first compaction technique is the vertical compaction technique described by Schilder.

The technique aims to obtain filling of the canal system in all its complexities, main and accessory canals.

The technique involves the master cone being inserted into the prepared canal and then proceeding with the insertion of a spreader, the tip of which is heated and quickly inserted into the body of the gutta-percha to then be quickly withdrawn.

The spreader has the purpose of removing part of the material so that the remaining material, softened by the heat, can be compacted with a special compactor.

The operation is repeated until the smallest compactor reaches 5 mm from the apex.

It is clear that this technique is very complex and laborious and consists of many tools, made of steel, rigid and large in size, dangerous for the stability of the root, so it has not had much diffusion, being relegated almost exclusively to specialists.

A more recent variant, directly derived from Schilder’s technique, is the so-called “Continuous Wave” proposed by Buchanan, wherein a specific tool is used which operates both as a heat carrier and as a compactor of the gutta-percha.

In this case, the compacting heat carrier must reach at least 5-7 mm from the apex.

In reality, the distance of 5-7 mm is inadequate to allow correct plasticization of the apical gutta-percha.

It is a scientific reality that the phase transition in gutta-percha, downstream of the tip of the heat carrier, develops only 3 mm into the gutta-percha mass. Traditional techniques for root canal treatment of teeth therefore do not ensure that the root canal is completely and accurately filled with filling material. Experience has shown that incomplete obturation of the root canal is the primary cause of failure of endodontic therapy.

After heating the gutta-percha, the material is compacted on the walls of the apical third of the root canal and at the apex.

Compaction occurs by applying pressure to the hot material with a cold tool. The heat input, in addition to determining the transformation of the gutta-percha, determines a volumetric increase in the material, followed by a contraction during cooling which produces voids in the material. To obtain a valid adaptation of the material to the canal walls, the cooling of the guttapercha has to be associated with an effective compaction technique that allows it to return to its original configuration.

The known techniques, however, are affected by the same drawbacks, the first of which is represented by the fact that they do not produce thermal increases valid for the purpose of obtaining and a sufficient viscoelastic modification of the gutta-percha in the last mm of the canal, where the endodontic system is mostly represented.

In fact, in long and narrow canals it is clinically impossible to bring, if not at the expense of large removals of dentin from the canal walls, the thinnest compactor to a depth of 4 mm from the end of the canal, a depth considered sufficient to allow thermoplasticization of the apical gutta-percha.

As matter of fact, by bringing the heat carrier to a distance of 5 mm from the end of the preparation, a modest thermal increase in the apical gutta-percha mass is obtained (approximately 2°C), which alone is not sufficient to determine adequate plasticization, for which a thermal increase of 4-8°C more than body temperature is required.

A drawback is also represented by the sudden mode of transmission of the temperature to the heating tip.

The heating of the gutta-percha occurs by conduction with the contact between the heater and the cone and determines the phase transition of the gutta-percha which passes from a solid form to a plastic form.

It must be considered that gutta-percha is a poor conductor of heat, so the slow movement of the particles of the material and the thermal equilibrium reached in a short time, in the case of sudden heat transmission, make the heating ineffective, while, for the heat flow is continuous, the temperature of the hot body must always be higher than the cold body.

This circumstance improves the quality of the obturation both vertically and laterally. Last but not least, if the compactor does not have a caliber related to the size of the canal to reach, without superior interference, 4 mm from the apex, it is also possible that the gutta-percha flows upwards between the compactor and the canal wall, instead of flow downwards and sideways to fill the canal itself. Furthermore, the rigidity of the metal used to build the compactors, in the curvatures of the canals, allows reaching the distance of 4 mm from the end of the preparation only in the case of an excessively flared canal preparation, certainly exposing the tooth to a notable weakening, increasing the risk of fracture and/or iatrogenic errors during shaping.

An example of a tool for endodontic treatment is disclosed in 102001900944110, in the name of the same inventor, to whom reference should be made for a more detailed description of the gutta-percha insertion and compaction technique which can also be carried out using the tool according to the present invention.

US6106283 discloses an endodontic instrument for making fillings which involves the use of a heated tip in accordance with the preamble of claim 1.

However, the heating of the tip occurs simply by activating heating means at regular intervals but without any control of the temperature reached by the tip.

Scope of the invention

The object of the present invention is to overcome the above drawbacks, by providing a tool for endodontic treatment characterized by high efficiency.

A particular object is to provide a tool for endodontic treatment which allows for the most efficient, complete and deep filling of the gutta-percha, avoiding both its rising and the formation of voids, so reducing as much as possible the risk of incomplete fillings of the root canals.

Yet another object is to provide a tool for endodontic treatment characterized by variable canal morphology and which is ductile and flexible to reach the apical third without interference, respecting the anatomical-structural shape of the root.

Not the least object is to provide a tool for endodontic treatment which allows faster and more effective filling of the canals in order to reduce the application time of the technique.

These objects, as well as others that will become more apparent hereinafter, are achieved by a tool for endodontic treatment which involves the insertion of a predetermined quantity of a therm of ormable material into a root canal to be filled for its subsequent compaction, which tool, according to claim 1, comprises a handpiece suitable to be grasped by a technician, a flexible tip associated with said handpiece to facilitate the heating of the thermoformable material, heating means for heating said flexible tip controlled by an electronic driving circuit suitable for heating said tip from a minimum temperature to a maximum temperature by electrically powering said tip with a gradual temperature rise ramp provided with temperature stabilization intervals, one or more tools for compacting the heated thermoformable material.

In this way, the gradual increase in temperature will not produce an immediate thermal equilibrium and will allow the thermoformable material, usually gutta-percha or a gutta-percha-based mixture, to acquire more heat and distribute it to a greater depth.

In this way, the tip will be heated with successive increases in temperature to transform the thermoformable material into plastic form also and above all in the last mm of the canal, so as to adapt it to the walls of the apex and to the apex itself with one or more flexible compactors and without shape memory.

Advantageously, the compacting tool will be made entirely of titanium, i.e. a material without shape memory, to make the tool adaptable to the variable canal morphology, ductile and flexible to reach the apical third without interference, respecting the anatomical -structural shape of the root.

Conveniently, the compacting tool will be flexible and will have a conical shape with a first end proximal to its handpiece and a second end distal to the handpiece and having a caliber between 0.30mm and 0.50mm.

In particular, the flexible compactor tool will be selected within a group of compactor tools having differentiated caliber at said second end and with a value equal to one between 0.30mm, 0.35mm, 0.40mm, 0.45mm, 0, 50mm.

In this way, it will always be possible to select a compacting tool with a caliber as similar as possible to the dimensions of the canal in the apical third in order to exert an effective pressure, avoiding the risk of using tools that are too small and which would not constitute a barrier to the reaction forces that could allow the thermoformable material to rise through the space between the walls of the root canal and those of the tip itself, causing ineffective compaction.

Advantageous embodiments of the invention are obtained in accordance with the dependent claims.

Brief disclosure of the drawings

Further features and advantages of the invention will become more apparent in the light of the detailed description of a preferred but not exclusive embodiment of a tool for endodontic treatment, shown by way of a non-limiting example with the aid of the attached drawing tables in which:

FIG. 1 is a schematic view of the tool;

FIG. 2 is a diagram showing the rise ramp of the heating temperature of the tip;

FIG. 3 is a schematic diagram of a compacting tool.

Best mode of carrying out the invention

Fig- 1 shows a schematic configuration of the tool for endodontic treatment according to the present invention, indicated globally with 1.

The tool 1 essentially consists of a hardware part and a software part.

The hardware part comprises a handpiece 2 suitable of being grasped by the operator and which houses thereinto the electronic command and management means operating via a microchip controller, a two-line signaling display 3, a battery pack 4, a spindle 5 in stainless steel, a flexible tip 6 removably coupled to the spindle 5.

One or more compacting tools 10 are also provided, one of which is schematized in Fig. 3, suitable of being associated with a different handpiece, not illustrated, or other gripping means to act on the thermoformable material following its heating using the tip 6.

The software part is instead provided with an algorithm suitable of controlling all the operating parameters and in particular the electronic control means.

The latter also operate as heating means, feeding the tip 6 with current for its heating to facilitate the heating and compaction of the thermoformable material used in the treatment, usually gutta-percha or gutta-percha-based mixture.

The heating means are controlled by an electronic driving circuit designed to heat the flexible tip 6 from a minimum temperature to a maximum temperature by electrically powering the tip 6 with a gradual temperature rise ramp provided with temperature stabilization intervals. Furthermore, the heating means are provided with sensors that detect the specific temperature, to allow control of the ramp through the software.

Fig. 2 shows a possible temperature rise ramp from a minimum value of 50°C to a maximum value of 190°C and stabilization intervals each lasting one second.

Each stabilization interval will be characterized by a respective temperature having a value increased by 10°C compared to the immediately previous stabilization interval. Preferably, the tip 6 will be electrically powered for an on period of 15 seconds. In this way it is guaranteed that the temperature value read by the sensors is precise and that at the end of the cycle the temperature value is the one desired for the good operation of the tool.

Furthermore, the software will be designed to allow the data to be displayed on display 3 of the handpiece 2 and for the charging control of the battery pack 4.

According to a further particularly advantageous aspect, as can be seen from Fig. 3, the compacting tool 10 will have a conical shape with a first end 7 proximal to the respective handpiece and a second end 8 distal to the handpiece and designed to be inserted into the root canal to operate as compactor of therm of ormable material.

Advantageously, the compacting tool 10 will have a flexible structure and will be made entirely of titanium.

Conveniently, the distal end 8 will have a caliber between 0.30mm and 0.50mm.

Preferably, the tool 1 will be provided with a set of compacting tools 10 different from each other in the caliber of their distal end 8.

The compacting tools 10 will be adapted to be applied to their spindle in a selective and removable manner to allow the replacement of the compacting tool applied from time to time, both if replacement is necessary due to wear and in the case in which it must be replaced by a compacting tool of different caliber, i.e. they may be equipped with their own handpiece.

Advantageously, the compacting tool 10 will be selected from a group of compactors which comprises at least one compactor for each caliber value equal to 0.30mm, 0.35mm, 0.40mm, 0.45mm, 0.50mm.

Again in a particularly advantageous manner, the compacting tools of the group, regardless of the caliber of their distal end 8, will all have the same diameter value at a first section DI located at a first distance dl, for example equal to 10mm, from the second distal end 8 and the same diameter value at a second section D2 located at a second distance d2, for example equal to 20mm, from the second distal end 8.

Preferably, the diameter of the first section Dl will be equal to 0.65mm, while the diameter of the second section D2 will preferably be equal to 1.45mm.

According to a particular variant, the tool may be provided with the above titanium compacting tool with one of the caliber values indicated above or with the above set of titanium compacting tools, without however also being provided with the heating means in accordance with the present invention, which instead may be of the traditional type and for example as described in the above cited patent 102001900944110.

In this case, the tool will equally have the advantages of using a titanium compactor and/or the advantages of using a set of interchangeable compactors with selected calibers.

From an operational point of view, if the handpiece is not supplied already calibrated for the supplied tip or if it is necessary to replace the tip, it will be necessary to carry out the calibration first and then proceed with use.

The procedure for use requires that the selected tip is inserted into the appropriate spindle and positioned in such a way that the handpiece display always remains clearly visible to the operator.

To start the cycle, simply press the touch button on the handpiece, starting the cycle which can be controlled via the display or via the sound signal emitted by the handpiece.

The duration of the cycle will be 15 seconds, at the end of which there will be a prolonged sound signal.

During the operating period, the product electronics will power the tip, controlling its temperature to always guarantee the correct value.

If necessary, the cycle can be interrupted by pressing the button on the handpiece again. The tip used, being subjected to continuous heating and having a very thin diameter at the distal end, will suffer wear which will not always allow maximum efficiency, making it necessary to replace it with a new tip which will have to be calibrated.

Claims

1. A tool for endodontic treatment, wherein a treatment provides the insertion of a predetermined amount of a thermoformable material in a root canal to be filled for its subsequent compaction, which tool comprises: a handpiece (2) adapted to be grasped by a technician; a flexible tip (6) applied to said handpiece (2) to promote the heating of the thermoformable material; heating means for heating said flexible tip (6); at least one compacting tool (10) of the thermoformable material characterized in that said heating means are controlled by an electronic driving circuit adapted to heat said flexible tip (6) from a minimum temperature to a maximum temperature by electrically feeding said flexible tip (6) with a gradual temperature rise ramp provided with temperature stabilization intervals.

2. Tool as claimed in claim 1, characterized in that said each of said stabilization intervals has a duration of one second.

3. Tool as claimed in claim 1 or 2, characterized in that said flexible tip (6) is electrically powered for a powering period of 15 seconds.

4. Tool as claimed in any preceding claim, characterized in that said maximum temperature is equal to 190 ° C.

5. Tool as claimed in any preceding claim, characterized in that for each of said stabilization intervals the respective temperature has an increased value of 10°C with respect to the previous stabilization interval.

6. Tool as claimed in any preceding claim, characterized in that said at least one compacting tool (10) has flexible structure and is made of titanium.

7. Tool as claimed in any preceding claim, characterized in that said at least one compacting tool (10) has a conical shape with a first end (7) proximal to said handpiece (2) and a second end (8) distal to said handpiece (2) and having a caliber between 0.30mm and 0.50mm.

8. Tool as claimed in any preceding claim, characterized in that said at least one compacting tool (10) is selected into a group of compacting tools having different caliber for the respective second distal ends (8) and of a value equal to one between 0.30mm, 0.35mm, 0.40mm, 0.45mm, 0.50mm.

9. Tool as claimed in claim 8, characterized in that the compacting tools (10) of said group have the same diameter value at a first section (DI) placed at a first distance from said second distal end (8), said diameter having a value preferably equal to 0.65mm.

10. Tool as claimed in claim 8 or 9, characterized in that the compacting tools (10) of said group have the same diameter value at a second section (D2) placed at a second distance from said second distal end (8), said diameter having a value preferably equal to 1.45mm.