An abrasion device

Abstract

An abrasion device adapted to deliver abrasive powder using a gas medium, comprising a reservoir socket (10), adapted to receive the reservoir in its first position and to hold the reservoir in its second position, with the reservoir socket (10) being equipped with a securing assembly (12) designed to lock a main valve assembly (20) when the reservoir is in any position other than the second position, and to release a lock on the valve when the reservoir is in the second position. The main valve assembly (20) is adapted to disconnect a high-pressure system from a column mixer and open the main valve connecting the reservoir space to a mixing chamber space (30) when the main valve lock is released, and a reservoir opening assembly (21) is adapted for opening the reservoir when the main valve connecting the reservoir space to the mixing chamber space (30) is opened.

Description

[0001] AN ABRASION DEVICE

[0002] The invention relates to an abrasion device, specifically designed for the removal of dental caries. The invention is applicable in dental practices, either as standalone equipment or integrated with dental chairs.

[0003] A widely acknowledged issue in dentistry is the absence of a non-invasive method for treating dental caries. Currently, the conventional and, in practice, sole method of treating dental caries is the use of a dental drill. Dentists use drills to remove decayed tissue and subsequently restore the cavity with a suitable material, such as a composite. Unfortunately, drilling is invasive and entails numerous drawbacks and potential side effects. Most notably, it is a technique that causes pain for patients. This presents a significant medical and social issue, as it causes fear of dental visits. This fear discourages regular visits to the dentist, often resulting in patients seeking treatment only when caries is significantly advanced, frequently leading to tooth necrosis and the necessity for root canal treatment. Fear of dentists is particularly significant in children, who may sometimes develop trauma related to such visits. Pain associated with drilling often necessitates anaesthesia, increasing procedure costs and, in rare cases, causing significant side effects, not to mention prolonged swelling and numbness in the oral cavity. Pain caused by the drilling method results from elevated temperatures, reaching several hundred degrees due to the high rotational speed of the drill. This substantial temperature increase necessitates the use of cooling, creating a temperature gradient that may cause to microerosion of the enamel. In contrast, during abrasion, the enamel surface temperature does not rise and may even decrease slightly. Abrasion maintains consistent efficiency, while drills wear out with each procedure, becoming blunt after several uses and requiring disposal. Teeth surfaces treated with abrasion are dry and ready for filling. By contrast, drilling leaves a so-called smear layer on the cavity's walls and floor, comprising enamel particles, dentine, dentinal fluid, saliva, water, cooling system oil, and microorganisms. This smear layer requires etching with phosphoric acid, which, in cases of deep caries, can chemically damage the pulp, often leading to pulp diseases or chemical necrosis. Abrasion does not harm the living pulp tissue, even when the pulp is exposed. Furthermore, drills have the disadvantage of relatively low precision. During caries removal, drills often remove a significant amount of adjacent healthy tissue, which is clearly disadvantageous to the patient.

[0004] Importantly, drills also negatively affect dentists' health. Prolonged use of high-speed drills, which generate significant vibrations and noise, negatively impacts dentists' hearing as well as their musculoskeletal and nervous systems, especially in the upper limbs.

[0005] Abrasion devices for use in dental procedures are known in the state of the art. Specifically, publication PL194147B1 discloses a method for visualising and removing dental caries. This method involves preliminary sandblasting of the tooth surface using a soft abrasive, such as baking soda, under a pressure of 8 to 11 atm (0.81 MPa to 1.11 MPa), followed by caries removal with a hard abrasive, such as aluminium oxide, at the same pressure. The publication further discloses a sandblasting device for visualising and removing dental caries. This device consists of at least one mixing chamber connected to a compressed gas medium source via a valve cut-off system and a foot pedal. The mixing chamber on the other end is connected to a working handle for visualising and / or removing caries.

[0006] The essence of the invention is an abrasion device adapted to deliver an abrasive medium using a gas medium, comprising a source of pressurised gas medium; a column mixer with a mixing chamber; and a tube with a working tip. The device according to the invention is characterised in that the mixing chamber of the column mixer is adapted to be filled from above with abrasive powder from reservoirs through a main valve assembly equipped with a main valve. Furthermore, the device according to the invention is characterised by being equipped with a reservoir socket designed to receive an abrasive medium reservoir in a first position and hold the reservoir in a second position. The reservoir socket includes a securing assembly configured to lock the main valve assembly when the reservoir is in any position other than the second position and to release the lock when the reservoir is in the second position. The main valve assembly is configured to isolate the high-pressure system from the column mixer and to open the main valve, which connects the reservoir space to the mixing chamber, once the main valve lock is released. Additionally, the reservoir opening assembly is designed to open the reservoir when the main valve connecting the reservoir space to the mixing chamber space is opened.

[0007] Preferably, the device according to the invention is characterised by a valve assembly equipped with a chute in the form of a funnel, connecting the reservoir socket to the main valve.

[0008] Preferably, the device according to the invention is characterised in that the main valve is a ball valve.

[0009] Preferably, the device according to the invention is characterised in that the securing assembly is in the form of a ring provided with a locking protrusion, where the ring of the securing assembly rotates around its axis along with the reservoir, moving between the reservoir's first and second positions, such that the locking protrusion allows the main valve to open only when the reservoir is in the second position.

[0010] Preferably, the device according to the invention is characterised in that the source of the gas medium supplies the gas medium at a pressure of up to 1 .2 MPa.

[0011] Preferably, the device according to the invention is characterised in that the abrasive medium is aluminium oxide (AI2O3, corundum) with a particle diameter of up to 150 m.

[0012] The device according to the invention advantageously enables painless and rapid removal of dental caries, serving as an alternative to the invasive drill method. The device according to the invention enables procedures without requiring anaesthesia or cooling, thereby avoiding the potential side effects associated with drills. The device operates using non-contact technology, maintaining a distance of approximately 2-4 mm between the working tip and the tooth surface, and does not generate high temperatures, thereby eliminating pain.

[0013] The device benefits both patients and dentists, as it does not generate the noise or vibrations associated with drills, which adversely affect dentists' musculoskeletal systems. Compared to existing sandblasting devices, the device according to the invention enables not only sandblasting but also the treatment of all classes of caries, with significantly reduced abrasive consumption and dust generation.

[0014] Furthermore, the device incorporates an additional safety feature that permits the replacement of the abrasive reservoir only when the operating pressure is disengaged.

[0015] The invention is further illustrated in a favourable embodiment through the following figures, where:

[0016] Fig. 1 schematically depicts the device according to the invention;

[0017] Fig. 2 shows the column mixer of the device according to the invention;

[0018] Fig. 3 presents a cross-section of the column mixer of the device according to the invention.

[0019] Fig. 1 schematically illustrates the device of the invention. The diagram in Fig. 1 illustrates the general layout of the device according to the invention, highlighting the pneumatic system.

[0020] In the device according to the invention, the gas medium is supplied through an inlet connector 2. Preferably, the gas medium can be directed into a multiplier with a hopper or passed directly to subsequent parts of the system. In the pneumatic system, one branch leads to a control circuit with a foot pedal 5, while the other leads to a process valve 4. The control branch with the foot pedal 5 also includes an operating mode selection system, equipped with a mode selector switch 6. The mode selector switch 6 enables selection between two control sub-systems: one for uniform impulse durations and another for non-uniform (variable) impulse durations. The uniform impulse system includes a timer valve 7 that generates a cycle of impulses with a fixed, defined duration. The system for non-uniform (variable) impulse durations does not include a timer valve. In this mode, the user determines the duration of each impulse. Both control sub-systems are connected via a connector to the process valve 4, which controls the supply or cut-off of the gas medium to the column mixer 30. From the column mixer, the activated powder-gas mixture is directed to the working tip 3 of the device according to the invention.

[0021] The device according to the invention is connected to a cylinder of compressed air / medical gas or to a compressor with a booster. For this application, these are collectively referred to as the gas medium. The column mixer is then filled with the abrasive medium via a transfer mechanism that moves the abrasive from the reservoir to the column mixer. In a preferred embodiment, where the device includes two column mixers with different abrasive media, one mixer is selected as active. This selection is performed through the control panel. The control panel is also used to select the operating mode, which includes configuring the sequence of automatic pressure delivery and cut-off, with optional operator intervention in the ongoing sequence. The control panel also allows selection of the desired working pressure, achieved via a pressure regulator or a compressor with adjustable output pressure in one embodiment. Once configured, the device enters working mode, awaiting activation by the dentist via the foot pedal 5, a standard element in dentistry used to operate dental chairs. Pressing the foot pedal automatically triggers compressed gas impulses. In non-uniform (variable) impulse duration mode, the operator can manually control the duration of compressed gas impulses by adjusting the gas medium flow via the foot pedal. Gas medium impulses pass through the pneumatic system and, preferably, through a cleaning and drying system before reaching the column mixer 30, where a powder-gas mixture is formed. The powder-gas mixture is subsequently directed through a pneumatic hose and expelled through a nozzle, which the dentist uses to perform procedures in the patient's oral cavity. After the procedure, the nozzle's working tip is removed and sterilised before reuse. The device according to the invention enables the refilling of the abrasive medium as needed.

[0022] In a preferred embodiment, the device is powered by a compressed air cylinder. In another advantageous embodiment, it uses a standard dental compressor and booster with a stabilising hopper, supplying pressurised air through inlet 15. The preferred abrasive medium is aluminium oxide (AI2O3, corundum) with a particle size of 90 m, ideally ranging from 90 to 150 pm. The abrasive medium is conveyed in a powderair mixture from the column mixer chamber 30 via outlet 14. The device operates at pressures up to 1.2 MPa, with a working pressure range of approximately 0.8 to 1 .2 MPa for caries treatment.

[0023] The device operates by generating a pressurised powder-air mixture in the column mixer chamber 30, which is expelled through the nozzle under pressure, striking the dentine to perform abrasive treatment. The nozzle's working tip is preferably constructed from sintered carbide (tungsten carbide, silicon carbide, or carbide mixtures with additives), enabling it to withstand the impact of hard aluminium oxide particles under high pressure.

[0024] Preferably, the device operates in one of two impulse modes. The abrasive mixture may be delivered in uniform-duration impulses or in impulses followed by a gas medium blow-off to clear the treatment area, with the blow-off ceasing only upon release of the foot pedal 5.

[0025] The nozzle's working tip is removable and sterilised before each use. Preferably, the device according to the invention includes two columns, where the second column may be used with an abrasive medium (AI2O3) of a different particle size or as a sandblasting column (with a softer abrasive of smaller particle size). In summary, the abrasion device according to the invention is adapted to deliver abrasive powder via a gas medium and includes a pressurised gas medium source, at least one, and preferably two column mixers 1 with a mixing chamber 30 and a tube with a working tip.

[0026] Fig. 2 illustrates a column mixer 1 according to a preferred embodiment of the invention. The column mixer 1 is equipped with a mixing chamber 30, which is adapted for top-loading with abrasive medium from reservoirs through a main valve assembly equipped with a main valve.

[0027] The reservoir socket 10 is configured to accept a reservoir in its first position and to secure it in its second position. The reservoir socket 10 allows the reservoir to rotate around a vertical axis between its first and second positions. In addition, the reservoir socket 10 is equipped with a securing assembly adapted to lock the main valve assembly when the reservoir is in any position other than the second position and to release the lock when the reservoir is in the second position. This means that the reservoir socket 10 is adapted to receive the reservoir containing the abrasive medium in its first position and to hold it in its second position, with the reservoir socket 10 being equipped with a securing assembly designed to lock the main valve assembly 22 when the reservoir is in any position other than the second position and to release the lock on the main valve 22 when the reservoir is in the second position.

[0028] The securing assembly takes the form of a ring provided with a locking protrusion 12, where the ring of the securing assembly rotates around its axis together with the reservoir between the reservoir's first and second positions, such that the locking protrusion 12 allows the main valve 22 to open only when the reservoir is in the second position. The locking protrusion 12 is mechanically coupled to the cam disc 20 of the main valve assembly.

[0029] The main valve assembly comprises a main shaft 17 that holds the ball valve 22 and a cam disc (20), both mounted on the main shaft 17. The main valve assembly also includes an auxiliary shaft 18 that supports an opening element 21 designed to open the reservoir containing the abrasive medium. The opening element 21 of the reservoir is designed to open the reservoir during the opening of the main valve, which connects the reservoir space to the mixing chamber 30. The opening element 21 is shaped as a tooth driver and is configured to rotate the reservoir's closing lid to open it when seated in the socket 10. The auxiliary shaft 18 terminates in a cam 16 that follows a cam track formed in the cam disc 20. The shape of the cam track on the cam disc forces the movement of the cam 16 along the track, thereby rotating the auxiliary shaft 18 along with the opening element 21 , in synchrony with the movement of the main shaft 17 and the opening of the main valve 22. The main shaft is manually rotated using a lever (not shown).

[0030] The cam disc 20 is also equipped with an additional cam track segment that interacts with the roller of the limit switch guide 19. The shape of the cam track on the cam disc 20, interacting with the roller of the limit switch guide 19, is shaped so that the limit switch 19 cuts off the pressure supply to the system when the main shaft is in any position other than the one corresponding to the closure of the main valve 22. This means that the cam disc 20 is equipped with a cam track segment specifically shaped to disconnect the high-pressure system from the column mixer and to open the main valve 22, which connects the reservoir space to the mixing chamber 30, and this is only possible when the main valve lock is released. Therefore, the main valve assembly is designed to disconnect the high-pressure system from the column mixer and to open the main valve 22, connecting the reservoir space to the mixing chamber 30, when the main valve lock is released.

[0031] The main valve assembly is equipped with a chute in the form of a funnel 13 that connects the reservoir socket 10 to the main valve 22. As noted earlier, the main valve is preferably a ball valve 22. Fig. 3 illustrates a cross-section of the column mixer of the device according to the invention. From the top, the device shows the socket 10, the funnel 13, and the opening element 21 mounted on the auxiliary shaft. The main valve 22 is positioned on the main shaft within the channel connecting to the funnel 13. Below the main valve lies the chamber 30, which houses a gas flow damper 31. Compressed air, serving as the gas medium, is fed from the inlet side through the inlet 15 into the gas flow damper 31 , and then passes through perforations in the walls of the damper 31 , agitating the abrasive medium resting at the bottom of the mixer chamber 30. The supply of high-pressure air generates a mixture of the abrasive medium and the gas medium, which flows through the outlet 14 and then through a flexible hose to the working tip operated by the dentist. The device according to the invention is filled with the abrasive medium from above by inserting the reservoir into the reservoir socket 10 in its first position. The reservoir is then rotated within the socket to its second position, where the locking protrusion 12 disengages the lock on the main valve assembly. The rotation of the main shaft 17 along with the cam disc 20, triggers the limit switch 19, rotates the main valve 22, and simultaneously turns the auxiliary shaft 18 and the opening element 21 which opens the reservoir. The abrasive medium falls through the open ball valve to the bottom of the mixing chamber 30 under the force of gravity. Rotating the main shaft in the opposite direction closes the main valve 22, and once it is fully closed, the limit switch permits pressure to be delivered to the mixing chamber.

Claims

Patent claims1 . An abrasion device adapted to deliver an abrasive medium using a gas medium, comprising a pressurised gas medium source; a column mixer (1) with a mixing chamber (30); a tube with a working tip, characterised in that the mixing chamber (30) of the column mixer is adapted to be top-loaded with abrasive powder from reservoirs through a main valve assembly equipped with a main valve (22), and further comprising a reservoir socket (10) adapted to receive the reservoir containing the abrasive medium in its first position and to hold the reservoir in its second position, with the reservoir socket (10) being equipped with a securing assembly designed to lock the main valve assembly (22) when the reservoir is in a position other than the second position and to release the lock on the main valve (22) when the reservoir is in the second position, a main valve assembly designed to disconnect the high-pressure system from the column mixer and to open the main valve (22), connecting the reservoir space to the mixing chamber (30), when the lock on the main valve is disengaged, and an opening element (21 ) of the reservoir designed to open the reservoir during the opening of the main valve, which connects the reservoir space to the mixing chamber (30).

2. The device according to claim 1 , characterised in that the valve assembly is equipped with a chute in the form of a funnel (13) connecting the reservoir socket (10) to the main valve.

3. The device according to claim 1 or 2, characterised in that the main valve is a ball valve (22).

4. The device according to any one of claims 1 to 3, characterised in that the securing assembly is in the form of a ring provided with a locking protrusion (12), where the ring of the securing assembly rotates around its axis together with the reservoir between reservoir's first and second positions, such that the locking protrusion allows the main valve to open only when the reservoir is in the second position.

5. The device according to any one of claims 1 to 4, characterised in that the gas medium source supplies the gas medium at a pressure of up to 1 .2 MPa.

6. The device according to any one of claims 1 to 5, characterised in that the abrasive medium is aluminium oxide (AI2O3, corundum) with a particle size of up to 150 pm.

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