Systems and methods for removing foreign objects from root canals

In some embodiments, a method for removing a foreign object from a root canal of a tooth is disclosed. The method can include positioning a fluid generator to be in fluid communication with the root canal of the tooth. Fluid can be supplied to the root canal. The method can include generating fluid motion and/or pressure waves in the fluid in the root canal with the fluid motion generator. The foreign object can be removed from the root canal with the pressure waves and/or the fluid motion.

BACKGROUND

Field

The field relates to systems and methods for removing foreign objects (e.g., a separated instrument) from a root canal of a subject, and in particular, for using a fluid motion generator to remove the foreign object.

Description of the Related Art

In conventional root canal procedures, a file or other mechanical instrument is inserted into the root canal of the patient to mechanically separate the diseased tissue from the tooth and remove the separated tissue from the root canal spaces. Sometimes, the file or other instrument may unintentionally break inside the tooth (e.g., inside the root canal). Broken instruments inside the tooth may cause pain to the patient, may increase the risk of infection, and may reduce the overall health outcomes for the patient. Moreover, broken or separated instruments, or indeed other foreign objects, may prevent access to the apex and impede thorough cleaning, shaping, and sealing of the root canal. Accordingly, there remains a continuing need for systems and methods to remove separated instruments from a tooth.

SUMMARY

Various non-limiting aspects of the present disclosure will now be provided to illustrate features of the disclosed apparatus, methods, and compositions. Examples of apparatus, methods, and compositions for endodontic treatments are provided

In one embodiment, a method for removing a foreign object from a root canal of a tooth is disclosed. The method can include positioning a fluid motion generator to be in fluid communication with the root canal of the tooth. The method can include supplying fluid to the root canal. The method can include generating fluid motion in the root canal with the fluid motion generator. The method can include moving the foreign object with the fluid motion in a proximal direction towards the fluid motion generator.

In another embodiment, a method for removing a foreign object from a root canal of a tooth is disclosed. The method can include positioning a pressure wave generator to be in fluid communication with the root canal of the tooth. The method can include supplying fluid to the root canal. The method can include generating pressure waves and fluid motion in the root canal with the pressure wave generator. The method can include dislodging the foreign object from the root canal with the generated pressure waves.

In another embodiment, a system for removing a foreign object from a root canal of a tooth is disclosed. The system can include a fluid motion generator configured to generate fluid motion in the root canal with the fluid motion generator and to move the foreign object from the root canal with the fluid motion in a proximal direction towards the fluid motion generator. The system can include a controller operably coupled with the fluid motion generator. The controller can be configured to receive a user selection signal indicative of a selected treatment procedure, the selected treatment procedure comprising a procedure to move the foreign object. The controller can be configured to determine system parameters associated with the selected treatment procedure. The controller can be configured to transmit instructions to system components to operate the fluid motion generator to cause the foreign object to move in the proximal direction.

In another embodiment, a system for removing a foreign object from a root canal of a tooth is disclosed. The system can include a pressure wave generator configured to generate pressure waves and fluid motion in the root canal with the pressure wave generator and to dislodge the foreign object from the root canal with the generated pressure waves. In some embodiments, the pressure wave generator can be configured to move the foreign object in a proximal direction towards the pressure wave generator. The system can include a controller operably coupled with the pressure wave generator. The controller can be configured to receive a user selection signal indicative of a selected treatment procedure, the selected treatment procedure comprising a procedure to move or dislodge the foreign object. The controller can be configured to determine system parameters associated with the selected treatment procedure. The controller can be configured to transmit instructions to system components to operate the pressure wave generator to dislodge the foreign object and/or to cause the foreign object to move in a proximal direction.

All possible combinations and subcombinations of the aspects and embodiments described in this application are contemplated. For purposes of this summary, certain aspects, advantages, and novel features of certain disclosed inventions are summarized. It is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the inventions disclosed herein may be embodied or carried out in a manner that achieves one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein. Further, the foregoing is intended to summarize certain disclosed inventions and is not intended to limit the scope of the inventions disclosed herein.

Throughout the drawings, reference numbers may be re-used to indicate a general correspondence between referenced elements. The drawings are provided to illustrate example embodiments described herein and are not intended to limit the scope of the disclosure.

DETAILED DESCRIPTION

Various embodiments disclosed herein utilize a fluid motion generator (which may comprise a pressure wave generator in various embodiments) to remove a foreign object (such as a separated dental instrument) from a root canal of a tooth. During a conventional root canal treatment procedure, a clinician typically creates an access opening into the interior of the tooth, e.g., into the pulp chamber. The clinician may insert a dental instrument, such as a file, ultrasonic tip, fiber tip, drill, burr, etc., into the tooth to remove diseased tissue, organic materials, and/or inorganic materials from the tooth. To remove diseased tissue and other materials from the root canal spaces, the clinician may insert the instrument into the root canal spaces. The root canals may be relatively small in diameter, and/or may include curved canals. As the clinician maneuvers the instrument (e.g., file (hand file, rotary file, etc.), ultrasonic tip, etc.) inside the root canal, the instrument may bend or otherwise be exposed to mechanical stresses. In some procedures, the instrument may break or otherwise become separated from the clinician, such that the separated instrument remains in the tooth (e.g., in the root canal). Such separated instruments may reduce the overall health outcomes for the patient and may lead to pain and/or infection. Separated instruments may also impede thorough cleaning, shaping, and sealing of the root canal system. Moreover, other foreign objects (e.g., objects introduced from outside the tooth) may enter the root canal system during various portions of a treatment procedure.

Accordingly, it can be advantageous to remove foreign objects (e.g., a separated instrument) without damaging the tooth. However, it can be challenging to use conventional instruments to retrieve the separated instrument, for example, due to the small spaces in which the separated instrument is located (e.g., a root canal). Many efforts to remove separated instruments require the clinician to widen the canals in order to visually inspect the separated instrument, and/or to physically remove dentin or other dental material that surrounds or is proximate to the foreign object. It can be important with conventional instruments to have a straight-line view of the separated instrument in order to remove it, which can be challenging in teeth with thin and/or curved roots. Such invasive procedures can be detrimental to the health of the tooth and/or the comfort of the patient.

In some embodiments disclosed herein, a fluid motion generator, which can comprise a pressure wave generator (such as a liquid jet device, a laser device, etc.), can be used to remove the separated instrument without damaging the tooth and without further enlarging the canal spaces. Beneficially, the fluid motion generator can remove the separated instrument without inserting the fluid motion generator into the root canal. Rather, a distal end of the fluid motion generator can be disposed outside the root canal. In some embodiments, the distal end of the fluid motion generator (e.g., a pressure wave generator) can be disposed in the pulp chamber outside the root canal. In some embodiments, the distal end of the fluid motion generator can be disposed in a chamber positioned against the tooth (and thus outside the root canal). The fluid motion generator can be activated to supply fluid to the root canal and to generate fluid motion (such as vortices, swirling motion, etc.) inside the root canal.

The fluid motion can agitate the foreign object and cause the foreign object to move proximally in the root canal towards the fluid motion generator. In some embodiments, suction can be applied to the tooth to enhance the proximal movement of the foreign object. In some embodiments, the fluid motion generator can comprise a pressure wave generator, which can generate pressure waves (including broadband pressure waves with multiple frequencies) inside the fluid. The generated pressure waves can further agitate the foreign object and/or can dislodge the foreign object if it is stuck inside the canal system. As explained herein, the generated pressure waves can have broadband frequencies with one or more frequencies corresponding to resonant frequencies of the foreign object. Agitating or vibrating the foreign object at or near such resonant frequencies can help dislodge and/or move the foreign object. In some embodiments, the fluid motion generator and/or pressure wave generator can clean organic debris disposed about the foreign object. Removing the organic debris or unhealthy materials from around the foreign object can also, or alternatively, help in dislodging and/or moving the foreign object. The fluid motion generator can completely remove the foreign object from the root canal in some embodiments. In such embodiments, the foreign object can be removed from the root canal and can be drawn into a chamber pressed against the tooth. In other embodiments, the foreign object can be moved proximally towards the fluid motion generator by a sufficient amount such that the clinician can manually retrieve the foreign object without enlarging or further shaping the canals to access the foreign object. Additional details of the file removal systems and methods may be found in Wohlgemuth, et al., “Effectiveness of the GentleWave System in Removing Separated Instruments,”Journal of Endodontics,vol. 41, no. 11, November 2015, which is hereby incorporated by reference herein in its entirety and for all purposes. Additional details of fluid motion generators (including pressure wave generators) may be found in U.S. Pat. No. 9,492,244; U.S. Patent Publication No. US 2012/0237893; U.S. Patent Publication No. US 2014/0220505; and U.S. Patent Publication No. US 2016/0095679, the entire contents of each of which are hereby incorporated by reference herein in their entirety and for all purposes.

I. Examples of Methods and Systems for Removing Foreign Objects from a Tooth

A. Systems and Methods for Removing Foreign Objects from Molar Teeth

FIG. 1Ais a schematic side sectional view of a tooth10having a foreign object12in a root canal15. The tooth10shown inFIG. 1Ais a molar, however, the embodiments disclosed herein may be used with other types of teeth (such as pre-molars, incisors, canines, etc.). Moreover, the tooth10can be a human tooth or a tooth of any other mammal. During some treatments, the clinician may create an access opening18in the tooth10so as to expose the pulp chamber28and the root canal15. As shown inFIG. 1A, the foreign object12may comprise a broken or otherwise separated instrument which is stuck in the root canal15of the tooth10. In some treatments, for example, the foreign object12may comprise at least a portion of a file, ultrasonic tip, fiber optic tip, or other instrument which fractures due to torsional, bending, and/or cyclic loading conditions. In other treatments, the foreign object12may comprise an entire treatment instrument that the clinician drops or leaves in the tooth10. In some arrangements, the foreign object12may comprise any other suitable object which does not naturally reside in the tooth. As explained above, it can be important to remove the foreign object12, without further enlarging or damaging the canal system, in order to improve health outcomes for the patient.

In some treatments, the foreign object may be visually obscured or hidden from the clinician (out of the clinician's line of sight), such that the clinician cannot see part or all of the foreign object in the root canal system. For example, some root canals15may be curved or angled such that the lower portion (e.g., lower third) of the root canal15and the foreign object12are hidden from the clinician. In some treatments, for example, the foreign object (e.g., separated instrument) may be in a root canal that is curved greater than 30°. In some treatments, the foreign object may be visible to the clinician, and/or may be in a root canal that is curved less than 30°. Beneficially, the embodiments disclosed herein can move the foreign object12proximally towards the fluid motion generator (and/or entirely remove the foreign object12) when the foreign object12is visible to the clinician (e.g., within the line of sight) and when the foreign object12(or a portion thereof) is hidden or obscured from the clinician (e.g. when the canal15is curved or angled).

FIG. 1Bis a schematic side sectional view of the tooth10and foreign object12ofFIG. 1Aduring a treatment procedure with a treatment system1according to various embodiments disclosed herein. The system can comprise a fluid platform61including a treatment instrument50(which may comprise a handpiece) having a distal portion58sized and shaped to be pressed against or attached to the tooth10(e.g., by way of a tooth seal75or other platform coupled with the tooth). The fluid platform61can comprise a fluid retainer66(e.g., a cap70and a flow restrictor68). The cap70and flow restrictor68can be disposed over the access opening18of the tooth10and can cooperate to seal the treatment region from the outside environs. In some embodiments, the flow restrictor68can comprise a sponge or other flexible material that helps to prevent fluid from entering and/or leaving the treatment region through the cap70.

A fluid motion generator5can be coupled to or formed with the fluid platform. InFIG. 1B, the fluid motion generator5can comprise a pressure wave generator64and a fluid inlet71configured to deliver fluid to at least partially fill the tooth10. The pressure wave generator64can be activated to generate pressure waves in the fluid supplied to the root canal15and pulp chamber28. As explained herein, the supplied fluid can comprise a degassed liquid. Moreover, as explained herein, the generated pressure waves can have multiple frequencies and a broadband power spectrum. The pressure wave generator can comprise any suitable type of pressure wave generator, including, e.g., a liquid jet device, a laser device, etc. Additional details of example pressure wave generators may be found throughout U.S. Patent Publication No. US 2012/0237893, the entire contents of which are incorporated by reference herein in its entirety and for all purposes.

The fluid inlet71may be in fluid communication with a fluid reservoir, supply, or source that provides the fluid to be delivered to the tooth10via the inlet71. The fluid may be delivered under pressure, for example, by use of one or more pumps or by using a gravity feed (e.g., by raising the height of the fluid reservoir above the height of the tooth chamber). The fluid platform61may include additional components including, e.g., pressure regulators, pressure sensors, valves, etc. In some cases, a pressure sensor may be disposed in a tooth chamber, to measure the pressure in the tooth chamber during treatment.

The flow of fluid from the inlet71may cause or augment fluid movement in the tooth chamber to clean the tooth10and/or to move the foreign object12in a proximal direction P towards the fluid motion generator5. For example, under various conditions of fluid inflow rate, pressure, inlet diameter, and so forth, the flow that is generated may cause (or augment) circulation, agitation, turbulence, etc. in the tooth chamber, which may improve irrigation and/or movement of the foreign object12. Fluid may be at least partially retained in a fluid chamber defined at least in part by an internal chamber69in the fluid retainer66and the tooth chamber (e.g., the pulp chamber28and the root canals15). The fluid chamber may be at least partially filled with fluid. In some advantageous embodiments, the fluid chamber may be substantially or completely filled with fluid during a treatment procedure, including procedures for removing a foreign object. During treatment, the fluid inlet71and the fluid outlet72can be in fluid communication with fluid retained in the fluid chamber. In the embodiment illustrated inFIG. 1B, both the fluid inlet71and the fluid outlet72are in fluid communication with the fluid in the internal chamber69, the pulp chamber28, and the root canal15, and fluid can flow into the tooth from the fluid inlet71(solid arrowed lines92ainFIG. 1B) and be removed from the tooth via the fluid outlet72(solid arrowed line92binFIG. 1B). The delivery of fluid into the chamber via the fluid inlet71can cause a circulation in the tooth chamber (see, e.g., arrowed lines92a).

In addition, the fluid platform can comprise a fluid outlet72and one or more vents73. The fluid outlet72can be connected to a vacuum pump and can apply suction to the treatment region to remove fluid from the tooth10. The vent73can permit fluid from the tooth chamber to flow out of the vent73, for example if the fluid pressure becomes too large in the chamber. The vent73can act as a relief valve to inhibit over-pressurization of the tooth chamber.

In some embodiments, the vent73comprises a directionally biased valve that permits fluid to leave the tooth chamber but inhibits ambient air from entering the tooth chamber. For example, the vent73may comprise one or more one-way (or check) valves. A one-way valve may have a cracking pressure selected to permit fluid to leave the tooth chamber when the fluid pressure in the tooth chamber exceeds a pressure threshold (e.g., about 100 mmHg in some cases). In other embodiments, a one-way valve may be used to permit ambient air to flow into the tooth chamber when the pressure differential between ambient conditions and the pressure in the tooth chamber is sufficiently large. For example, the cracking pressure of such a one-way valve may be selected such that if the fluid pressure in the chamber is less than a net (negative) threshold (e.g., the tooth chamber is under-pressurized), the valve will open to permit ambient air to flow into the fluid retainer66. Such ambient air may be suctioned out of the fluid retainer66via the fluid outlet72(e.g., the one-way valve may be disposed along the fluid outflow line). In some embodiments, the vents73comprise a one-way valve to permit fluid to leave the fluid retainer66(while inhibiting ambient air from entering), and a one-way valve to permit ambient air to enter the fluid retainer66. The cracking pressures of these two one-way valves may be selected so that in a desired pressure range, fluid is retained in the tooth chamber and ambient air is inhibited from entering the tooth chamber. For example, the pressure range in the tooth may be between about −100 mmHg and +100 mmHg.

In other embodiments, the vent73may be configured to permit air to enter the fluid outlet72and be entrained with fluid removed from the tooth chamber. For example, as shown inFIG. 1B, the vent73may be positioned and oriented such that ambient air flows into the fluid outlet72in the direction of the fluid flow in the outlet72(see, e.g., dashed arrowed line94a). In such embodiments, the flow in the fluid outlet72includes both fluid from the tooth chamber (see, e.g., solid arrowed line92b) and ambient air (see, e.g., dashed arrowed line94b). In some implementations, the vent73is disposed near the entry point of fluid into the outlet72, e.g., within a few millimeters, which may make it easier for fluid to flow from the tooth chamber if the pressure therein rises too high. In various embodiments, a plurality of vents73may be used such as, two, three, four, or more vents. The vents73may be sized, shaped, positioned, and/or oriented to allow fluid to flow from the tooth chamber while inhibiting air from entering the tooth chamber.

The example systems shown inFIG. 1Bcan assist in inducing fluid circulation in the tooth chamber due to the inflow of fluid from the fluid inlet71and/or the removal of fluid from the fluid outlet72. The example systems may also advantageously have patient safety features. For example, if the fluid outlet72is blocked (e.g., a suction tube is kinked or the suction ceases to function), the flow of fluid into the tooth chamber from the inlet71can lead to increasing fluid pressures, which can lead to the level of fluid rising up into the outlet72. The flow restrictor68(e.g., a sponge or a vent) can relieve the fluid pressure by allowing fluid to leave the tooth chamber (e.g., by flowing through the sponge or leaking out the vent). As another example, if the fluid inlet71is blocked (or ceases to function), the fluid outlet72may remove the fluid from the tooth chamber and may lead to increasingly lower pressures in the tooth chamber. The flow restrictor68can tend to keep the pressure in the tooth10at a safe or desirable level by allowing ambient air to flow into the fluid outlet72to at least partially alleviate the depressurization of the tooth chamber. Thus, by allowing the pressure in the tooth chamber to remain within safe or desirable bounds (e.g., above a lower pressure threshold and below an upper pressure threshold), certain such embodiments may provide advantages over closed fluid containers that do not include some form of fluid restrictor or pressure relief valve.

Accordingly, certain embodiments of the fluid platform61may be at least partially open to the ambient environment (e.g., via the flow restrictor68) and may substantially allow the pressure in the tooth chamber to self-regulate. An additional advantage of certain such embodiments can be that pressure regulators, pressure sensors, inlet/outlet control valves, etc. need not be used to monitor or regulate the pressure in the tooth chamber under treatment, because the self-regulation of the flow restrictor68permits the pressure to remain within desired or safe levels. In other embodiments, pressure regulators, pressure sensors, and control valves may be used to provide additional control over the fluid environment in the tooth. For example, pressure sensor(s) could be used to measure pressure along a fluid inlet71or a fluid outlet72, in a portion of the tooth chamber, etc. In yet other embodiments, a temperature sensor or temperature controller may be used to monitor or regulate the temperature of the fluid in the fluid inlet71or a fluid outlet72, in the tooth chamber, etc. Additional details of the fluid platform61and pressure wave generator64may be found throughout U.S. Patent Publication No. US 2012/0237893, which is incorporated by reference herein.

To remove the foreign object12from the tooth10, the clinician can press or attach the distal portion58of the treatment instrument50against the tooth10and can insert the fluid motion generator5(e.g., the pressure wave generator64) through the access opening18into a portion of the tooth10. In the illustrated embodiment, the distal end of the pressure wave generator64can be disposed outside the root canal15but inside the tooth10(e.g., inside the pulp chamber28). In other embodiments, the pressure wave generator64may be disposed outside the tooth10, e.g., inside the chamber69of the cap70. Fluid can be supplied to the tooth10, including the root canal15and other interior spaces of the tooth10. The pressure wave generator64can be activated to generate pressure waves67and fluid motion in the tooth and root canal15. The combination of the pressure waves67and the fluid motion92acan dislodge the foreign object12, even when the foreign object12is remote from the fluid motion generator5(e.g., remote from the distal end of the pressure wave generator64). Moreover, the pressure waves67and the fluid motion92acan dislodge the foreign object12when the foreign object12is obscured from the clinician, such as in situations in which part or all of the foreign object12is in the lower portion of a curved or angled root canal15. The clinician can maintain activation of the fluid motion generator5until the foreign object12is dislodged from the root canal15.

The pressure waves67and/or fluid motion92a, which may be enhanced or assisted by suction applied through the outlet72, can cause the foreign object12to move along the proximal direction P towards the fluid motion generator5. In some embodiments, the procedure can move the foreign object12such that at least a portion of the foreign object12is within the line of sight of the clinician, and the clinician can remove the foreign object12manually or using another instrument. For example, the fluid motion generator5can cause the foreign object12to move proximally such that a portion of the foreign object12is disposed in the pulp chamber28, and the clinician can manually, or with a tool, grasp the foreign object12and remove it from the tooth10. In other arrangements, the fluid motion generator5can cause the foreign object12to be entirely removed from the root canal15and the tooth10. Beneficially, the foreign object12can be moved (e.g., partially or fully removed) without requiring the root canal12to be enlarged. The foreign object12can be moved (e.g., partially or fully removed) without requiring the fluid motion generator5to contact the foreign object12. As explained above, in some embodiments, the foreign object12can be remote from the fluid motion generator5and at least partially visually hidden prior to moving the foreign object12. Moreover, the embodiments disclosed herein can remove the foreign object12without appreciably increasing the temperature in the tooth10. For example, the temperature in the tooth may not rise at all (e.g., may remain substantially constant), or the temperature may rise to temperatures tolerated by the body without damage thereto, for example, up to less than about 42° C. In various embodiments, the temperature may rise by less than 5° C.

FIG. 1Cis a schematic side sectional view of the tooth and foreign object ofFIG. 1Aduring a treatment procedure with a treatment system1comprising a fluid motion generator5that includes a liquid jet device, according to various embodiments disclosed herein. Unless otherwise noted, components ofFIG. 1Cmay be the same as or generally similar to like-numbered components ofFIG. 1B. For example, as withFIG. 1B, inFIG. 1C, the fluid motion generator5can comprise a pressure wave generator64. In the illustrated embodiment, the pressure wave generator64can comprise a liquid jet device having a guide tube100along which a liquid jet60can propagate. A nozzle (not shown) can be provided at the distal portion58to form a coherent, collimated liquid jet in various embodiments. An impingement member110can be provided at a distal end of the guide tube100and can deflect the jet60such that the jet60does not impact the anatomy directly, and does not enter the canals15. In the illustrated implementation the liquid jet device can be used to function as the inlet71and can deliver fluid to the tooth chamber (e.g., the pulp chamber28and the root canal(s)15) as well as generate pressure waves67in the chamber. Without being limited by theory, the interaction of the liquid jet60with liquid in the tooth chamber (e.g., stagnant fluid) can create pressure waves having multiple frequencies and broadband energy. Thus, the fluid motion generator5can comprise the liquid jet device, which can serve as the pressure wave generator64and the fluid inlet71in such implementations. The fluid from the liquid jet (as well as its conversion to a spray if an impingement plate is used) can induce circulation in the tooth chamber in addition to the pressure waves67.

For example, as explained throughout US 2012/0237893, which is incorporated by reference herein, the interaction of the jet60with the surrounding fluid can generate cavitation and acoustic waves which propagate throughout the root canal15, into the tubules, and into spaces which may not be visible to the clinician. In addition, the interaction of the jet60with the surrounding fluid can generate fluid motion, such as rotational motion (which may comprise turbulent motion), that circulates through the canals15. The generated pressure waves and/or fluid motion can cause the foreign object12to move along the proximal direction P towards the fluid motion generator5. In some embodiments, the foreign object12may be moved by the fluid motion generator5until a portion of the object12can be viewed by the clinician and manually removed or removed with another instrument. In other embodiments, the fluid motion generator5can be activated until the entire object12is removed from the root canal15and tooth10.

FIG. 1Dis a schematic side sectional view of a treatment system1configured to remove a foreign object12from the tooth10, with the treatment system1including one or more retaining devices77for retaining the foreign object after removal from the tooth10. In some embodiments, the retaining device77can be disposed in the internal chamber defined by the fluid platform61. In some embodiments, the retaining device77can be disposed distal (or downstream of) the outlet72. In other embodiments, the retaining device77can be disposed along the outlet72. In the illustrated arrangement, the retaining device77can be disposed around the fluid motion generator5. In some embodiments, the retaining device77can comprise a filter such that the foreign object12is not passed along the outlet72. In such embodiments, the filter may comprise a mesh or openings that are small enough to capture or retain the foreign object12but large enough to permit liquids and organic debris to pass therethrough. In some embodiments, the retaining device77can comprise a structural feature (such as a curved or tortuous pathway) or a bin to capture the removed foreign object12such that the foreign object12is not passed along the outlet72. Thus, in various embodiments, the retaining device77can be provided in the fluid platform61(e.g., within a chamber of the fluid platform61) so as to capture or retain the foreign object12once it is removed from the tooth. In other embodiments, the foreign object12can be sucked into the outlet72and can pass into a waste reservoir or other reservoir within the system1(e.g., within a console).

B. Systems and Methods for Removing Foreign Objects from Pre-Molar Teeth

FIGS. 2A-2Billustrate additional examples of systems for removing a foreign object12from a root canal15of a tooth10. InFIGS. 2A-2B, the tooth10comprises a pre-molar tooth, but as explained above, the system1can be used to remove foreign objects12from any suitable type of tooth.FIG. 2Ais a schematic side sectional view of a system1, according to one embodiment.FIG. 2Bis a schematic top sectional view of the system1shown inFIG. 2A. As explained above, a fluid platform61(or tooth coupler) can be configured to be applied to (e.g., pressed against or attached to) a treatment region of the tooth10. A fluid motion generator5(which may comprise a pressure wave generator) can be activated to cause the foreign object12to move along the proximal direction P towards the fluid motion generator5. As explained above, fluid motion and/or pressure waves76can beneficially agitate the foreign object12and cause the foreign object12to move proximally. In various embodiments, the fluid motion generator5can also be activated to clean (or fill) the treatment region, simultaneously or sequentially with removing the foreign object12. The system1can include a console2configured to control the operation of the system1and one or more conduits4that provide fluid communication (and/or electrical or wireless/electronic communication) between the fluid platform61and the console2. The console2can include one or more fluid pumps and reservoirs that can supply liquids to the tooth10. The console2can also comprise a fluid removal system including a suction pump and a waste reservoir for removing liquids and waste materials from the tooth10by way of the conduit(s)4. The suction pump can assist in removing the foreign object12from the root canal15. The console2can also include one or more processors that are configured to electronically control the operation of the evacuation and/or delivery pumps to control and the delivery of liquid to the tooth and the removal of liquid from the tooth.

The system1shown inFIG. 2Acan include a fluid platform61that is sized and shaped to couple to a treatment region of the tooth10. For example, as explained above, the fluid platform61can comprise a distal portion of a handpiece that is manually pressed against the tooth by the clinician. In various embodiments, the fluid platform61can be attached to the tooth10for the treatment procedure. The fluid platform61can comprise a chamber6defined at least in part by an upper wall232and a side wall220that extends transversely from the upper wall232. When coupled to the tooth10(e.g., pressed against the tooth or attached to the tooth), the chamber6can retain liquid and other materials during a treatment procedure. The upper wall232and side wall220may be integrally formed as a single component in some embodiments; in other embodiments the upper wall232and side wall220may comprise separate components that are connected or joined together. The side wall220can extend annularly relative to the upper wall232to at least partially define the chamber6. It should be appreciated that the upper wall232, as used herein, refers to the wall near the proximal end of the chamber6; thus, during some treatments (such as those of upper teeth), the upper wall232may be disposed in a downward orientation.

In addition, the fluid platform61or chamber6can include a distal portion227configured to contact the treatment region of the tooth (or a portion thereof). The distal portion227can define an access port231that provides fluid communication between the chamber6and the treatment region of the tooth10(e.g., the root canal15). As explained above, in some procedures, a foreign object12may be disposed in the root canal15. In various arrangements, the distal portion227can taper radially inwardly towards a central axis Z of the fluid platform61and/or chamber6. The central axis Z can be perpendicular to and comprise a central axis of the access port231. For example, the side wall220can comprise a substantially conical taper that continuously and substantially linearly tapers inwardly and distally. Thus, as shown inFIG. 2A, a proximal portion of the chamber6can have an inner diameter D3(or other major dimension) and the access port231of the distal portion227can have an inner diameter D1(or other major dimension) that is smaller than D3. The chamber6may also have a height h. The height h of the chamber6can be less than about 5 cm in various embodiments, e.g., less than about 2 cm. Moreover, although not illustrated inFIG. 2A, a sealing member can be disposed about the chamber6and fluid platform61. The sealing member can comprise a compressive material (such as a foam) that can seal the treatment region when pressed against the tooth by the clinician. When pressed against the tooth, the fluid platform61can be urged into the tooth such that the sealing member is proximal the distal end of the fluid platform61.

As shown inFIG. 2A, the distal portion227can be inserted into or onto an access opening18of the tooth10to provide fluid communication with the root canal15. In some embodiments, a sealing material225may be applied between the distal portion227and the tooth10to create or enhance a fluid seal such that liquid, air, and/or debris does not escape to or from the chamber6and/or the tooth10. In other embodiments, no sealing material may be used. As shown inFIG. 2A, the distal portion227can be tapered such that the taper extends from an intermediate or proximal portion of the fluid platform61to the distal-most end of the fluid platform61. For example, as shown inFIG. 2A, the side wall220of the fluid platform61can comprise a generally straight or cylindrical portion203(along which the diameter D3remains substantially constant) and a tapered or conical portion204that tapers inwardly and distally from the straight portion203such that the inner diameter D1decreases along the distal direction (e.g., towards the tooth10inFIG. 2A). The tapered portion204can be disposed distal the straight portion203and can include the distal portion227and the distal-most end of the fluid platform61. Tapering the fluid platform61as shown inFIG. 2Acan advantageously enable the clinician to conduct treatment procedures on teeth of any size, including very small teeth or teeth that have very small root canal spaces, e.g., the smallest human tooth that would be treated by the system1. For example, the distal portion227can be sized to treat teeth with endodontic access openings having sizes (e.g., diameters or other major dimension) in a range of about 0.5 mm to about 5 mm.

The inner diameter D1of the access port231may be smaller than the access opening18of the tooth (e.g., the opening that the clinician forms to access the interior of the tooth), larger than the access opening, or the same size as the access opening. In some embodiments, advantageously, the outer diameter (and the inner diameter D1) of the access port231may be smaller than the access opening so as to enable the distal portion227to be inserted into the access opening. In other embodiments, the outer diameter of the distal portion227may be the same size as or larger than the access opening. Accordingly, the distal portion227of the fluid platform61may be inserted into the endodontic access opening such that the access port231and the access opening are substantially aligned and/or overlapping.

The inner diameter D1of the opening defined by the distal portion227can be in a range of about 0.3 mm (+/−0.05 mm) to about 5 mm (+/−1 mm), e.g., in a range of about 0.5 mm (+/−0.1 mm) to about 3 mm (+/−0.5 mm), or in a range of about 1 mm (+/−0.1 mm) to about 2 mm (+/−0.1 mm). The distal portion227of the fluid platform61may have a wall thickness in a range of about 0.001 mm (+/−0.0001 mm) to about 5 mm (+/−1 mm), e.g., in a range of about 0.01 mm (+/−0.001 mm) to about 1 mm (+/−0.1 mm). Further, the outer diameter of the distal portion227(e.g., the inner diameter D1plus twice the wall thickness of the distal portion227) may be in a range of about 0.5 mm (+/−0.1 mm) to about 5 mm (+/−1 mm), e.g., in a range of about 1 mm (+/−0.1 mm) to about 2 mm (+/−0.1 mm). The inner diameter D3of the proximal portion of the chamber6may be less than about 5 cm (+/−1 cm), e.g., less than about 1 cm (+/−0.1 cm). For example, the inner diameter D3may be in a range of about 0.5 cm (+/−0.1 cm) to about 1.5 cm (+/−0.3 cm), or in a range of about 0.7 cm (+/−0.1 cm) to about 1 cm (+/−0.1 cm). Moreover, as shown inFIG. 2A, the conical shape of the fluid platform61can have a tapering angle α that defines the amount by which an outside surface of the side wall220tapers inwardly and distally to the distal-most end of the fluid platform61. InFIG. 2A, an inner surface of the side wall220may not taper inwardly. However, in other embodiments, the inner surface of the side wall220may taper inwardly. The tapering angle α can be in a range of about 0° (+/−1°) to about 45° (+/−1°), or more particularly, in a range of about 0.5° (+/−0.1°) to about 45° (+/−1°), e.g., in a range of about 0.5° (+/−0.1°) to about 20° (+/−1°). In some embodiments, the tapering angle α can be in a range of about 1° (+/−0.1°) to about 15° (+/−1°), or in a range of about 1° (+/−0.1°) to about 10° (+/−1°).

The fluid motion generator5(which may also comprise a pressure wave generator, as described above) can be disposed on and/or through the side wall220of the fluid platform61. The fluid motion generator5can supply liquid221to the chamber6so as to generate rotational liquid motion in the chamber6. The supplied liquid221can comprise a degassed liquid as explained herein. The supplied liquid221can be any suitable type of treatment fluid, including, e.g., water, EDTA, bleach, etc. For example, a fluid inlet71can supply pressurized liquid221to the chamber6. InFIG. 2A, the pressurized liquid221can be passed through a nozzle210at a location in the side wall220of the fluid platform61(e.g., a sealing cap) at a location near the top wall232. As shown in the top sectional view ofFIG. 2B, the fluid motion generator5may be off-center or asymmetric relative to the fluid platform61or sealing cap. For example, the fluid inlet71and the nozzle210can be offset relative to the central axis Z of the fluid platform61. InFIG. 2B, the fluid motion generator can be radially offset relative to the central axis Z and can be directed in a direction X transverse to the central axis Z. As shown inFIG. 2A, the central axis Z can pass distally along the height h of the fluid platform61through the center of the access port231, e.g., the central axis Z can be transverse to the access port231at or near the center of the access port231. The central axis Z can also define the central longitudinal axis of the conical shape of the fluid platform61, e.g., transverse to the radial direction of the conical shape.

The pressurized liquid221supplied by the fluid motion generator5can induce liquid circulation in the chamber6of the fluid platform61. For example, the fluid motion generator5(e.g., the inlet71and/or nozzle210) can generate a swirling, rotational motion of influent liquid222about the central axis Z of the chamber, which can be transverse to (e.g., substantially perpendicular to in some arrangements) the X axis along which the liquid is introduced into the fluid platform61. In some arrangements, rotational or circulatory motion can also be induced about other directions, e.g., about an axis parallel to the direction of fluid introduction. As shown inFIG. 2A, the influent liquid222can introduce rotational flow near and/or along walls205of the canal spaces15as the rotating liquid222enters the canal spaces15.

In some embodiments, the pressurized liquid221can pass through the nozzle210and can emerge as a coherent, collimated liquid jet, which can act as a fluid motion generator and/or pressure wave generator, as explained above. In various embodiments of the nozzle210, an orifice or opening in the nozzle may have a diameter d1at an inlet or a diameter d2at an outlet that may be in a range from about 5 microns to about 1000 microns. Other diameter ranges are possible. In various embodiments, one or both of the diameters d1or d2of the nozzle opening may be in a range from about 10 microns to about 100 microns, a range from about 100 microns to about 500 microns, or range from about 500 microns to about 1000 microns. In various other embodiments, one or both of the orifice diameters d1or d2may be in a range of about 40-80 microns, a range of about 45-70 microns, or a range of about 45-65 microns. In one embodiment, the orifice diameter d1is about 60 microns. The ratio of axial length L1to diameter d1, the ratio of axial length L2to diameter d2, or the ratio of total axial length L1+L2to diameter d1, d2, or average diameter (d1+d2)/2 may, in various embodiments, be about 50:1, about 20:1, about 10:1, about 5:1, about 1:1, or less. In one embodiment, the axial length L1is about 500 microns. Additional examples of nozzles may be found in U.S. Patent Publication No. US 2011/0117517, which is incorporated by reference herein.

In some embodiments, the liquid221may comprise a stream of liquid that is not a jet, or that is not a circular jet. After entering the chamber6, the liquid221can impact the side wall220of the fluid platform61. In some arrangements, the jet may impact an impingement surface before entering the chamber, e.g., a surface in the inlet path leading to chamber6. The angle of the jet at the impact may be adjusted such that the impact leads to minimal loss of momentum. The fluid motion generator5can be angled such that, upon impingement of the liquid221against the wall220, a rotating sheet of influent liquid222is generated in which the sheet of influent liquid222rotates in a swirling motion about the central axis Z and travels distally along the side wall220in the chamber6towards the opening231in the fluid platform. The rotating sheet of influent liquid222can continue downward along the inner walls205of the root canal(s)15towards the apical opening of the tooth10. The rapid, rotating fluid motion (and/or the pressure waves67) can dislodge or otherwise cause the foreign object12to move proximally P towards the fluid motion generator5. In addition, the rotating liquid222can effectively and efficiently clean the entire root canal space15. For example, the rapid, bulk fluid motion of the influent liquid222can interact with diseased matter in the root canal15and can dislodge or otherwise remove the diseased matter from the root canal15. As explained above, the system1shown inFIGS. 2A-2Bcan be used to clean portions of the root canal15around the foreign object12. In some embodiments, for example, the portions of the root canal15proximate the foreign object12can be cleaned at the same time as the foreign object12is being dislodged by the fluid motion222and/or the pressure waves67. In other embodiments, the root canal15can be cleaned prior to or after removing the foreign object12.

As shown inFIG. 2B, it can be advantageous to orient the fluid motion generator5such that sufficient rotational influent flow222is provided in the chamber6and treatment region to cause the foreign object12to move in the proximal direction P. For example, the inlet71and nozzle210can be directed along the X-direction, which can be transverse to (e.g., perpendicular to) the central axis Z. The X-direction along which liquid is directed can be oriented at an angle between 80° and 100°, or more particularly, between 85° and 95°, relative to the central axis Z. The X-direction can be generally tangent to the outer edge of the side wall220. The X-direction may be slightly angled relative to the tangent T of the side wall220at the location at which the inlet221and nozzle210intersect the wall220of the chamber6. For example, the X-axis along which the ingoing liquid222is directed may be at an inlet angle θ relative to the tangent T. The inlet angle θ can be at or close to zero. For example, θ can be in a range of about 0° to about 15°, or in a range of about 0° to about 10°. In some embodiments, the angle θ can be in a range of about 1° to about 10°, or in a range of about 1° to about 5°. The fluid motion generator5can also be disposed such that the center of the influent stream222enters the chamber6at a distance δ, from the outermost edge of the wall220. The distance δ can be relatively small, e.g., in a range of about 5 μm to about 2 mm, or in a range of about 15 μm to about 40 μm. As shown inFIGS. 2A-2B, the fluid motion generator5can be oriented such that the X-axis is directed perpendicular to the central axis Z such that the X-axis is substantially horizontal relative to the chamber6. In some embodiments, the X-axis can be directed distally or proximally to assist in generating downward or upward rotating influent flow222into the treatment region. In some cases, the angle of impact θ, the angle of distal/proximal bias, and/or the shape of the impact region on the surface can be adjusted to adjust the flow properties that may affect efficacy of the procedure. The flow entering the chamber6may comprise one or more of the following: a jet impacting a surface of the chamber6which turns into a rotating sheet of fluid, a sheet of fluid (planar flow) as a result of impact of the jet onto a surface before entering the chamber, a planar flow generated via flowing a fluid through a slit, and/or any other suitable technique for generating a sheet of fluid

Furthermore, in the embodiment shown inFIG. 2A, when the liquid jet emerges from the nozzle210, the jet can interact with treatment liquid in an interaction zone230near the interface between the nozzle210and the chamber6. As explained above, the liquid jet can pass through the liquid and can generate pressure waves67that propagate through the liquid in the chamber6and root canal15of the tooth10. As shown inFIG. 2A, and as explained above, the pressure waves67can propagate from the interaction zone230distally into the canal15of the tooth10. The pressure waves67can comprise multiple frequencies that can cause liquid to flow into small spaces, cracks, and tubules of the tooth10to substantially clean the tooth10. Moreover, as explained above, the pressure waves67can agitate the foreign object12to cause the foreign object12to move proximally P. The combination of rotating influent liquid222and pressure waves67can therefore act to dislodge and move the foreign object12proximally P towards the fluid motion generator5. In some embodiments, the fluid motion generator5can cause the foreign object12to move into a more easily accessible location, and the clinician can manually (or with another instrument) remove the object12from the tooth10. In other embodiments, the fluid motion generator5can entirely remove the foreign object12from the tooth10. Moreover, the fluid motion generator5can create fluid motion and pressure waves sufficient to substantially clean the tooth, including large and small spaces of the tooth that may include different types and sizes of organic and inorganic matter.

It can be important to enable the influent liquid222to be removed from the treatment region to ensure that waste materials (e.g. dislodged foreign object12or debris, etc.) are irrigated from the tooth10and/or to enhance the fluid rotation at the treatment region. Accordingly, a fluid outlet72can be provided in and/or through the top wall232of the fluid platform61. The fluid outlet72can comprise a suction port233defining an opening between the chamber6and an outlet passage209(which may be one of the conduit(s)4described above) that conveys outgoing fluid to the waste system by way of a suction pump. The suction pump can apply suction to the outlet passage209and outlet72to draw fluids out of the chamber6and towards a reservoir outside the fluid platform61.

The fluid outlet72may have an inner diameter D2that is equal to or smaller than the inner diameter D1of the distal portion227of the chamber6of the fluid platform61. In other embodiments, the fluid outlet72may have an inner diameter D2that is larger than the inner diameter D1of the distal portion227. The relative size of D2and D1may be selected base on the desired type and rate of fluid flow. InFIG. 2A, the inner diameter D2is smaller than D1. The inner diameter D2may influence the depth at which the flow stagnates and changes direction (e.g., the return location V), from a spiraling downward motion next to the walls of the root canal to the spiraling upward motion through the interior of the influent flow222. For example, in some embodiments, the inner diameter D2of the suction port233may in a range of about 0.1 mm to about 5 mm, e.g., in a range of about 0.1 mm to about 2 mm. The fluid outlet72can be disposed at or near the center of the top wall232of the fluid platform61. As shown inFIG. 2A, the central axis Z of the fluid platform61and access port231can pass through both the access port231of the distal portion227and the suction port233of the outlet72. The central axis Z can be perpendicular, or substantially perpendicular, to the suction port233. For example, the central axis Z can be disposed at about a 90° angle (between 70° and 110°, or more particularly between 80° and 100°, or more particularly between 85° and 95°) relative to the suction port233. For example, in some embodiments, the access port231can define a plane that is transverse to (e.g., perpendicular to) the central axis Z, and the central axis Z can pass through the center of the access port23land through at least a portion of the suction port233. In some embodiments, the suction port233can define a plane that is transverse to (e.g., perpendicular to) the central axis Z, and the central axis Z can pass through the center of the suction port233and through at least a portion of the231access port231. In some embodiments, the access port23land the suction port233define respective planes that are both transverse to (e.g., perpendicular to) the central axis Z, and the central axis Z can pass through both the access port231and the suction port233. In some embodiments, the central axis Z can pass through the center of both the access port231and the suction port233. The suction port233can be symmetric about the central axis Z in some embodiments. In some embodiments, a center of the suction port233can lie on the central axis Z. In some embodiments, a flange62A of the outlet72can extend partially into the chamber6by a length p. The length p can be adjusted to improve the fluid outflow and/or fluid rotation in the chamber6and/or tooth10. The length p of the flange62A may also influence the depth of the return location V, e.g., the depth at which the flow stagnates and changes direction from spiral downward motion next to the walls to the spiral upward motion through the center. For example, the length p of the flange62A may be in a range of about 0.1 mm to about 10 mm. In some embodiments, the length p may be about the same as the height h of the chamber6, such that the flange62A extends downwardly to near the access port231.

The outlet72and chamber6can be configured such that the influent liquid222turns back proximally at a return location V to be drawn out of the chamber6. At the return location V (which may be at or near the apical opening15), the treatment liquid can turn back towards the fluid platform61in an outgoing fluid path224. The outgoing fluid path224may be different from the flow path or pattern of the influent liquid222. For example, the returning or outgoing flow224path can comprise rotational (or semi-planar) flow near the center of the canal spaces and/or within the swirling influent flow path222. In some embodiments, the outgoing flow224can comprise a spiral flow path that passes inside the rotating influent liquid222. The induced outward flow224can be carried outside the root canal15to carry the foreign object12away from the treatment region (e.g., outside the canal15and tooth10), or to a location more accessible by the clinician. Moreover, the suction provided by the outlet72and/or the rotating influent liquid222can provide a negative pressure at the apical opening15in which the foreign object12, the treatment liquid and/or waste is prevented from passing through the apical opening, which can reduce the risk of infection and/or pain to the patient. The outgoing liquid224can pass through the suction port233and can be drawn to the waste reservoir through the outlet line209by the suction pump. In addition, although not illustrated inFIG. 2A, a vent assembly can be provided to enhance the removal of waste fluids from the system. For example, one or more vents can be provided through the fluid platform61downstream of the suction port233. In addition, in some embodiments, an auxiliary port can be provided on the fluid platform61. The auxiliary port can include a one way valve, such as a duckbill valve. If the pressure inside the chamber6increases, for example, due to a clog in the outlet passage209, the rising pressure inside the chamber6may exceed the cracking pressure of the safety valve so that the valve can relieve pressure. The auxiliary safety valve may be disposed anywhere on the fluid platform61with at least one opening to the chamber6. Examples of vent assemblies can be found in, e.g., U.S. Patent Publication No. 2012/0237893, which is incorporated by reference herein in its entirety. Additional examples of systems1that include fluid motion generators5for removing foreign objects12from pre-molar (and other teeth) may be found throughout U.S. Patent Publication No. US 2016/0095679, the entire contents of which are hereby incorporated by reference herein in their entirety and for all purposes.

As with the embodiments ofFIGS. 1B-1C, to remove the foreign object12from the tooth10, the clinician can press or attach the distal portion of the treatment instrument against the tooth10. The fluid motion generator5(which can comprise a pressure wave generator) can be exposed to the internal chamber6of the fluid platform61. In the illustrated embodiment, the distal end of the fluid motion generator5(e.g., at or near where the nozzle210is exposed to the chamber6) can be disposed outside the tooth10and exposed to the chamber6. Fluid can be supplied to the tooth10, including the root canal15and other interior spaces of the tooth10. The fluid motion generator5can be activated to generate pressure waves67and influent fluid motion222in the tooth and root canal15. The combination of the pressure waves67and the fluid motion222can dislodge the foreign object12, even when the foreign object12is remote from the fluid motion generator5(e.g., remote from the chamber6and the nozzle210). Moreover, the pressure waves67and the fluid motion222can dislodge the foreign object12when the foreign object12is obscured from the clinician, such as in situations in which part or all of the foreign object12is in the lower portion of a curved or angled root canal15. The clinician can maintain activation of the fluid motion generator5until the foreign object12is dislodged from the root canal15.

The pressure waves67and/or fluid motion, which may be enhanced or assisted by suction applied through the suction port233and outlet72, can cause the foreign object12to move along the proximal direction P towards the fluid motion generator5. As explained about, fluid outflow224can pass within the influent flow path222to remove fluid and the foreign object12from the root canal12(or to cause proximal movement of the object12). In some embodiments, the procedure can move the foreign object12such that at least a portion of the foreign object12is within the line of sight of the clinician, and the clinician can remove the foreign object12manually or using another instrument. In other arrangements, the fluid motion generator5can cause the foreign object12to be entirely removed from the root canal15and the tooth10. Beneficially, the foreign object12can be moved (e.g., partially or fully removed) without requiring the root canal12to be enlarged. The foreign object12can be moved (e.g., partially or fully removed) without requiring the fluid motion generator5to contact the foreign object12. As explained above, in some embodiments, the foreign object12can be remote from the fluid motion generator5and at least partially visually hidden prior to moving the foreign object12. Moreover, the embodiments disclosed herein can remove the foreign object12without appreciably increasing the temperature in the tooth10. For example, the temperature in the tooth may not rise at all (e.g., may remain substantially constant), or the temperature may rise to temperatures tolerated by the body without damage thereto, for example, up to less than about 42° C. In various embodiments, the temperature may rise by less than 5° C. Further, as with the embodiment shown inFIG. 1D, the embodiment ofFIGS. 2A-2Bcan also include a retaining device, similar to the retaining device77shown inFIG. 1D. The retaining device can be configured to capture or retain the foreign object12after removal from the tooth.

FIG. 3is a flowchart illustrated an example method200for removing a foreign object from a root canal of a tooth. The tooth can comprise any suitable type of tooth, such as a molar, pre-molar, incisor, canine, etc. In a block202, a fluid motion generator (which can comprise a pressure wave generator) can be positioned to be in fluid communication with the root canal. As explained above, a fluid platform can be positioned over an access opening of the tooth to retain fluid in the tooth and root canal. The fluid motion generator can be disposed through an aperture of the fluid platform in some arrangements. In some embodiments, the fluid motion generator can be exposed to an inner chamber of the fluid platform (e.g., an inlet or nozzle can be exposed to the chamber). In some embodiments, the fluid motion generator (e.g., a pressure wave generator) can be disposed through the access opening and into a portion of the tooth (such as the pulp chamber). In other embodiments, the fluid motion generator may be disposed inside a chamber of the fluid platform and may be disposed outside the tooth. In some embodiments, the fluid motion generator can comprise a liquid jet device. In other embodiments, the pressure wave generator can comprise another suitable device, such as an electromagnetic device (e.g., a laser device), etc. Additional details of fluid motion generators and/or pressure wave generators may be found in U.S. Patent Publication No. US 2012/0237893 and in U.S. Patent Publication No. US 2016/0095679, the contents of each of which are incorporated by reference herein in its entirety and for all purposes.

Turning to a block204, treatment fluid can be supplied to the root canal. In some embodiments, a separate fluid inlet may supply the fluid to the tooth. In some embodiments, the fluid motion generator (such as a liquid jet device) may supply the fluid to the tooth. The treatment fluid may comprise any suitable type of fluid. For example, in some embodiments, the system can supply bleach (NaOCl), water, and/or ethylenediaminetetraacetic acid (EDTA) to the root canal. In some embodiments, NaOCl, water, EDTA, and water may be sequentially supplied to the root canal in one or more treatment phases. As explained in U.S. Patent Publication No. US 2012/0237893 and in U.S. Patent Publication No. US 2016/0095679 (both incorporated by reference herein), the treatment fluid can comprise degassed treatment fluid that is substantially free of dissolved gases. For example, the amount of dissolved oxygen (or dissolved air) may be less than about 5% by volume, less than about 1% by volume, less than about 0.5% by volume, or less than about 0.1% by volume.

In a block206, fluid motion and/or pressure waves can be generated in the fluid in the root canal with the fluid motion generator. In some arrangements, the generated pressure waves and/or fluid motion can clean portions of the root canal around the instrument. As explained herein and in U.S. Patent Publication No. US 2012/0237893 and in U.S. Patent Publication No. US 2016/0095679, the interaction of the jet with the surrounding treatment fluid can generate pressure waves and fluid motion in the tooth. As explained in U.S. Patent Publication No. US 2012/0237893 and in U.S. Patent Publication No. US 2016/0095679, the generated pressure waves can comprise multiple frequencies and a broadband power spectrum. For example, the generated pressure waves can have significant power extending from about 1 kHz to about 1000 kHz (e.g., the bandwidth may about 1000 kHz). The bandwidth of the acoustic energy spectrum may, in some cases, be measured in terms of the 3-decibel (3-dB) bandwidth (e.g., the full-width at half-maximum or FWHM of the acoustic power spectrum). In various examples, a broadband acoustic power spectrum may include significant power in a bandwidth in a range from about 1 kHz to about 500 kHz, in a range from about 10 kHz to about 100 kHz, or some other range of frequencies. In some implementations, a broadband spectrum may include acoustic power above about 1 MHz. In some embodiments, the pressure wave generator64can produce broadband acoustic power with peak power at about 10 kHz and a bandwidth of about 100 kHz. In various embodiments, the bandwidth of a broadband acoustic power spectrum is greater than about 10 kHz, greater than about 50 kHz, greater than about 100 kHz, greater than about 250 kHz, greater than about 500 kHz, greater than about 1 MHz, or some other value. In some cleaning methods, acoustic power between about 20 kHz and 200 kHz may be particularly effective. The acoustic power may have substantial power at frequencies greater than about 1 kHz, greater than about 10 kHz, greater than about 100 kHz, or greater than about 500 kHz. Substantial power can include, for example, an amount of power that is greater than 10%, greater than 25%, greater than 35%, or greater than 50% of the total acoustic power (e.g., the acoustic power integrated over all frequencies).

Moving to a block208, the foreign object can be moved proximally P towards the fluid motion generator5(and the clinician). In some embodiments, the foreign object12can be removed from the root canal with the pressure waves and/or the fluid motion. For example, the foreign object can be agitated and disturbed by a combination of the generated pressure waves and fluid motion, and can be moved out of the root canal and tooth. The vibrations provided by the pressure wave generator and the fluid motion can cause the object12(e.g., all or part of a file or other instrument) to move out of the root canal. Furthermore, as explained herein, the fluid outlet can apply suction to the treatment region to remove fluid from the tooth. The suction from the fluid outlet may contribute to pulling the foreign object out of the tooth. In other embodiments, the fluid motion generator may move the object12proximally by a sufficient amount such that the clinician can manually (or with another instrument) remove the object12from the tooth. In various embodiments, the fluid motion can comprise vortex flow, swirling flow, or other flow profiles, as illustrated and described herein.

In some embodiments, the fluid motion generator can be activated for at least 5 minutes to remove the foreign object from the tooth, e.g., for a time period in a range of 5 minutes to 12 minutes. In some embodiments, the fluid motion generator can be deactivated, and a subsequent treatment cycle can be performed by re-activating the fluid motion generator. In some embodiments, a plurality of treatment cycles can be performed for a total time period in a range of 10 minutes to 30 minutes.

In some embodiments, for example, NaOCl (e.g., 3% NaOCl) can be supplied by the fluid motion generator (or by a separate fluid inlet) for a first time period, distilled water can be supplied for a second time period, EDTA (e.g., 8% EDTA) can be supplied for a third time period, and distilled water can be supplied for a fourth time period. The first time period can be in a range of 1 minute to 10 minutes, or more particularly, in a range of 2 minutes to 8 minutes, or more particularly, in a range of 3 minutes to 6 minutes, e.g., 5 minutes. The second time period can be in a range of 10 seconds to 5 minutes, or more particularly, in a range of 10 seconds to 2 minutes, or more particularly, in a range of 20 seconds minutes to 1 minute, e.g., 30 seconds. The third time period can be in a range of 0.5 minutes to 6 minutes, in a range of 1 minute to 4 minutes, or in a range of 1 minute to 3 minutes, e.g., 2 minutes. The fourth time period can be in a range of 5 seconds to 2 minutes, in a range of 5 seconds to 1 minute, or in a range of 5 seconds to 30 seconds, e.g., 15 seconds. In some embodiments, the removed foreign object can comprise a file (such as #6, #8, #10, #15, or #20 K-files) or any other suitable instrument or portion thereof.

Moreover, in various embodiments, the fluid motion generator5disclosed herein can clean the root canal15with the foreign object12present in the canal15. In various arrangements, for example, the clinician can press the fluid platform61against the tooth and can activate the fluid motion generator5to clean diseased tissue from regions around the foreign object12while the object is present in the canal15. The pressure waves67and/or the fluid motion can agitate the foreign object and can the surrounding tissue so as to remove the diseased tissue from around the foreign object, even without removing the foreign object12from the tooth10. Thus, even in situations in which it is difficult or undesirable to remove the object12, the systems1disclosed herein can nevertheless effectively clean the root canals15and improve patient outcomes. In some embodiments, for example, the fluid motion generator5can simultaneously clean the root canals15of the tooth10and act to dislodge and move the foreign object proximally P towards the fluid motion generator5. In such a procedure, the pressure waves67and fluid motion can work to clean the root canals15and dislodge or move the foreign object12during the same procedure. In other embodiments, the clinician can clean the root canals15prior to removing the foreign object12. In still other embodiments, the clinician may remove the foreign object12prior to cleaning the canal15.

FIG. 4is a block diagram that schematically illustrates an embodiment of a system1configured to control the operation of a fluid motion generator5, which can comprise a pressure wave generator. The system1can be used in conjunction with the systems and methods ofFIGS. 1B-3. As explained above, the fluid motion generator or pressure wave generator can comprise any suitable type of device. In the illustrated embodiment, the fluid motion generator5comprises a pressure wave generator64adapted to generate a high-velocity jet60of fluid for use in dental procedures, including procedures for removing a foreign object12from a root canal15of a tooth10. The system1comprises a motor40, a fluid source44, a pump46, a pressure sensor48, a controller51, a user interface53, and a handpiece50that can be operated by a dental practitioner to supply fluid motion and/or pressure waves to the root canal of the tooth to remove the foreign object12and/or to clean the root canal15, as explained herein. The pump46can pressurize fluid received from the fluid source44. The pump46may comprise a piston pump in which the piston is actuatable by the motor40. The high-pressure liquid from the pump46can be fed to the pressure sensor48and then to the handpiece50, for example, by a length of high-pressure tubing49. The pressure sensor48may be used to sense the pressure of the liquid and communicate pressure information to the controller51. The controller51can use the pressure information to make adjustments to the motor40and/or the pump46to provide a target pressure for the fluid delivered to the handpiece50. For example, in embodiments in which the pump46comprises a piston pump, the controller51may signal the motor40to drive the piston more rapidly or more slowly, depending on the pressure information from the pressure sensor48. In some embodiments, the pressure of the liquid that can be delivered to the handpiece50can be adjusted within a range from about 500 psi to about 50,000 psi (1 psi is 1 pound per square inch and is about 6895 Pascal (Pa)). In certain embodiments, it has been found that a pressure range from about 2,000 psi to about 15,000 psi produces jets that are particularly effective for endodontic treatments. In some embodiments, the pressure is about 10,000 psi.

The fluid source44may comprise a fluid container (e.g., an intravenous bag) holding any of the treatments fluids described herein. The treatment fluid may be degassed, with a dissolved gas content less than normal (e.g., non-degassed) fluids. Examples of treatment fluids include sterile water, a medical-grade saline solution, an antiseptic or antibiotic solution (e.g., sodium hypochlorite), a solution with chemicals or medications, or any combination thereof. More than one fluid source may be used. In certain embodiments, it is advantageous for jet formation if the liquid provided by the fluid source44is substantially free of dissolved gases, which may reduce the effectiveness of the jet and the pressure wave generation. Therefore, in some embodiments, the fluid source44comprises degassed liquid such as, e.g., degassed distilled water. A bubble detector (not shown) may be disposed between the fluid source44and the pump46to detect bubbles in the liquid and/or to determine whether liquid flow from the fluid source44has been interrupted or the container has emptied. Also, as discussed above degassed fluids may be used. The bubble detector can be used to determine whether small air bubbles are present in the fluid that might negatively impact jet formation or acoustic wave propagation. Thus in some embodiments, a filter or de-bubbler (not shown) can be used to remove small air bubbles from the liquid. The liquid in the fluid source44may be at room temperature or may be heated and/or cooled to a different temperature. For example, in some embodiments, the liquid in the fluid source44can be chilled to reduce the temperature of the high velocity jet60generated by the system1, which may reduce or control the temperature of the fluid inside a tooth10. In some treatment methods, the liquid in the fluid source44can be heated, which may increase the rate of chemical reactions that may occur in the tooth10during treatment.

The handpiece50can be configured to receive the high pressure liquid and can be adapted at a distal end to generate a high-velocity beam or jet60of liquid for use in dental procedures. In some embodiments, the system1may produce a coherent, collimated jet of liquid. The handpiece50may be sized and shaped to be maneuverable in the mouth of a patient so that the jet60may be directed toward or away from various portions of the tooth10. In some embodiments, the handpiece50comprises a housing or cap that can be coupled to the tooth10.

The controller51may comprise a microprocessor, a special or general purpose computer, a floating point gate array, and/or a programmable logic device, that can be configured to process instructions stored on non-transitory computer-readable media (e.g., memory). The controller51may be used to control safety of the system1, for example, by limiting system pressures to be below safety thresholds and/or by limiting the time that the jet60is permitted to flow from the handpiece50. The system1may also include a user interface53that outputs relevant system data or accepts user input (e.g., a target pressure). In some embodiments, the user interface53comprises a touch screen graphics display. In some embodiments, the user interface53may include controls for a dental practitioner to operate the liquid jet apparatus. For example, the controls can include a foot switch to actuate or deactuate the jet.

The system1may include additional and/or different components and may be configured differently than shown inFIG. 4. For example, the system1may include an aspiration pump that is coupled to the handpiece50(or an aspiration cannula) to permit aspiration of the foreign object12and/or organic matter from the mouth or tooth10. In other embodiments, the system1may comprise other pneumatic and/or hydraulic systems adapted to generate the high-velocity beam or jet60.

Moreover, the controller51may be configured to operate in different modes, e.g., in a cleaning mode, in a foreign object removal mode, etc. In some embodiments, the parameters of the system1(e.g., fluid pressure, fluid type, etc.) may be adjusted based on the type of procedure, for example, based on whether the procedure is a cleaning procedure, a foreign object removal procedure, or a combined procedure that simultaneous cleans the tooth and removes (or moves) the foreign object. The controller51can be configured to communicate with the user interface53to present the clinician or user with multiple options for a treatment procedure. For example, the user interface53can comprise a display or other device that prompts the clinician to select a treatment mode. The clinician can interact with the user interface53(e.g., by way of a touch screen display, keyboard, etc.) to select a mode, such as a foreign object removal mode or a combined mode that simultaneously cleans and moves a foreign object. Once the user selects a mode, the user interface53can be configured to transmit a user selection signal to the controller51. Based on the user selection signal, the controller51can be configured to determine the parameters of the system1(such as pressure, flow rate, type and sequence of fluid delivery, treatment time, etc.) to be used in conjunction with the selected procedure. The controller51can send instructions to the various system components (such as the motor40) to initiate and manage the selected procedure. Once the selected procedure is completed, the user interface53can prompt the user for additional treatment procedures.

In some embodiments, the system1can comprise a sensor configured to transduce a signal (e.g., a pressure signal, an optical signal, a flow rate signal, etc.), and based on the transduced signal, the controller51can determine whether the foreign object12has been removed from the tooth10. For example, in some embodiments, based on the transduced signal, the controller51can determine that the foreign object12has been removed and can send a signal to the user interface53to indicate to the clinician that the foreign object12has been removed. In some embodiments, the controller51can determine that the foreign object12has been captured within the fluid platform61, e.g., within a bin, filter, or pathway of the fluid platform61. In some embodiments, once a determination has been made by the controller51that the foreign object12has been removed from the tooth10, the controller51can automatically place the system1in another treatment mode (such as a cleaning mode) and the treatment procedure (e.g., a cleaning procedure) can be continued. In some embodiments, once a determination has been made by the controller51that the foreign object12has been removed from the tooth10, the clinician can manually select another treatment mode (such as a cleaning mode). Furthermore, in various embodiments, the clinician can select from the user interface53one or more system parameters that can assist in removing the foreign object12. For example, in some embodiments, the clinician can select or adjust system parameters for an object removal procedure based on one or more of size, shape and location of the foreign object12and/or based on the anatomy of the treatment tooth. In some embodiments, for example, the clinician can select the pump pressure (which may, in turn, tune the acoustic energy and/or fluid dynamics) in order to remove the foreign object12from the tooth10.

The components of the system1disclosed herein may be housed in a console, which may be similar to the console2ofFIG. 2A. Additional examples of components of the system1may be found throughout U.S. Patent Publication No. US 2012/0237893 and U.S. Pat. No. 9,504,536, the contents of each of which are hereby incorporated by reference herein in their entirety and for all purposes.

FIGS. 5A and 5Bare example radiographs illustrating the results of the foreign object removal procedures described herein, before and after removal of a foreign object12from the canals15. In particular,FIGS. 5A-5Billustrate removal of files having three different sizes, #10 K-files, #15 K-files, and #20 K-files, from apical regions (FIG. 5A) and midroot regions (FIG. 5B) of teeth. In the example procedures, the system1was operated as described herein for a molar tooth, e.g., in conjunction with the embodiments ofFIGS. 1B-1C. During the object removal procedure, 3% NaOCl was supplied and the fluid motion generator was activated for 5 minutes, distilled water was supplied and the fluid motion generator was activated for 30 seconds, 8% EDTA was supplied and the fluid motion generator was activated for 2 minutes, and distilled water was supplied and the fluid motion generator was activated for 15 seconds, sequentially (a total treatment time of 7 minutes). A maximum of three treatment cycles was performed. As shown inFIGS. 5A and 5B, in various example tests, the foreign object12was completely removed from the tooth after the procedure.

Although the tooth10schematically depicted in some of the figures is a molar, the procedures may be performed on any type of tooth such as an incisor, a canine, a bicuspid, a pre-molar, or a molar. Further, although the tooth may be depicted as a lower (mandibular) tooth in the figures, this is for purposes of illustration, and is not limiting. The systems, methods, and compositions may be applied to lower (mandibular) teeth or upper (maxillary) teeth. Also, the disclosed apparatus and methods are capable of treating root canal spaces having a wide range of morphologies, including highly curved root canal spaces. Moreover, the disclosed apparatus, methods, and compositions may be applied to human teeth (including juvenile teeth) and/or to animal teeth.

II. Examples of Pressure Wave Generators

In various embodiments, the fluid motion generator5can comprise a pressure wave generator64. The pressure wave generator64can be used in various disclosed embodiments to move or remove a foreign object12from a tooth10. In various embodiments, as explained above, the pressure wave generator64can be used to clean the tooth10, e.g., whether simultaneously or sequentially with removing the foreign object12. In some embodiments, the pressure wave generator5can comprise an elongated member having an active distal end portion. The active distal end portion can be activated by a user to apply energy to the treatment tooth10to dislodge and move the foreign object12. The applied energy can also be used to remove unhealthy or undesirable material from the tooth10.

As explained herein, the disclosed pressure wave generators64can be configured to generate pressure waves67and fluid motion with energy sufficient to remove the foreign object12and/or to clean undesirable material from a tooth10. The pressure wave generator64can be a device that converts one form of energy into acoustic waves and bulk fluid motion (e.g., rotational motion) within the fluid in the root canal15. The fluid motion generator5and/or the pressure wave generator64can induce, among other phenomena, both pressure waves and bulk fluid dynamic motion in the fluid (e.g., in the chamber6or in the canals15), fluid circulation, turbulence, vortices and other conditions that can enable the cleaning of the tooth. The pressure wave generator64disclosed in each of the figures described herein may be any suitable type of pressure wave generator.

The pressure wave generator64may also create cavitation, acoustic streaming, turbulence, etc. In various embodiments, the pressure wave generator64can generate pressure waves or acoustic energy having a broadband power spectrum (see, e.g.,FIGS. 6A-6C). For example, the pressure wave generator64can generate pressure waves at multiple different frequencies, as opposed to only one or a few frequencies. Without being limited by theory, it is believed that the generation of power at multiple frequencies can help dislodge the foreign object12in object removal procedures and to remove various types of organic and/or inorganic materials that have different material or physical characteristics at various frequencies.

(1) Liquid Jet Apparatus

For example, in some embodiments, the pressure wave generator64can comprise a liquid jet device. The liquid jet can be created by passing high pressure liquid through an orifice. The liquid jet can create pressure waves within the treatment liquid. In some embodiments, the pressure wave generator64comprises a coherent, collimated jet of liquid. The jet of liquid can interact with liquid in a substantially-enclosed volume (e.g., the chamber and/or the mouth of the user) and/or an impingement member to create the acoustic waves. In addition, the interaction of the jet and the treatment fluid, as well as the interaction of the spray which results from hitting the impingement member and the treatment fluid, may assist in creating cavitation and/or other acoustic effects to remove the foreign object12and/or to clean the tooth.

In various embodiments, the liquid jet device can comprise a positioning member (e.g., a guide tube) having a channel or lumen along which or through which a liquid jet can propagate. The distal end portion of the positioning member can include one or more openings that permit the deflected liquid to exit the positioning member and interact with the surrounding environment in the chamber6or tooth10. In some treatment methods, the openings disposed at or near the distal end portion of the positioning member can be submerged in liquid that can be at least partially enclosed in the chamber6attached to or enclosing a portion of the tooth10. In some embodiments, the liquid jet can pass through the guide tube and can impact an impingement surface. The passage of the jet through the surrounding treatment fluid and impact of the jet on the impingement surface can generate the acoustic waves in some implementations. The flow of the submerged portion of the liquid jet may generate a cavitation cloud within the treatment fluid. The creation and collapse of the cavitation cloud may, in some cases, generate a substantial hydroacoustic field in or near the tooth. Further cavitation effects may be possible, including growth, oscillation, and collapse of cavitation bubbles. In addition, as explained above, bulk fluid motion, such as rotational flow, may be induced. The induced rotational flow can enhance the movement of the foreign object12and various cleaning processes by removing detached material and replenishing reactants for the cleaning reactions.

Additional details of a pressure wave generator and/or pressure wave generator that includes a liquid jet device may be found at least in ¶¶[0045]-[0050], [0054]-[0077] and various other portions of U.S. Patent Publication No. US 2011/0117517, published May 19, 2011, and in ¶¶[0136]-[0142] and various other portions of U.S. Patent Publication No. US 2012/0237893, published Sep. 20, 2012, each of which is incorporated by reference herein in its entirety and for all purposes.

As has been described, a pressure wave generator can be any physical device or phenomenon that converts one form of energy into acoustic waves within the treatment fluid and that induces rotational fluid motion in the chamber6and/or tooth10. Many different types of pressure wave generators (or combinations of pressure wave generators) are usable with embodiments of the systems and methods disclosed herein.

(2) Mechanical Energy

Mechanical energy pressure wave generators can also include rotating objects, e.g. miniature propellers, eccentrically-confined rotating cylinders, a perforated rotating disk, etc. These types of pressure wave generators can also include vibrating, oscillating, or pulsating objects such as sonication devices that create pressure waves via piezoelectricity, magnetostriction, etc. In some pressure wave generators, electric energy transferred to a piezoelectric transducer can produce acoustic waves in the treatment fluid. In some cases, the piezoelectric transducer can be used to create acoustic waves having a broad band of frequencies.

(3) Electromagnetic Energy

An electromagnetic beam of radiation (e.g., a laser beam) can propagate energy into a chamber, and the electromagnetic beam energy can be transformed into acoustic waves as it enters the treatment fluid. In some embodiments, the laser beam can be directed into the chamber6as a collimated and coherent beam of light. The collimated laser beam can be sufficient to generate pressure waves as the laser beam delivers energy to the fluid. Furthermore, in various embodiments, the laser beam can be focused using one or more lenses or other focusing devices to concentrate the optical energy at a location in the treatment fluid. The concentrated energy can be transformed into pressure waves sufficient to clean the undesirable materials. In one embodiment, the wavelength of the laser beam or electromagnetic source can be selected to be highly absorbable by the treatment fluid in the chamber or mouth (e.g., water) and/or by the additives in the treatment fluid (e.g., nanoparticles, etc.). For example, at least some of the electromagnetic energy may be absorbed by the fluid (e.g., water) in the chamber, which can generate localized heating and pressure waves that propagate in the fluid. The pressure waves generated by the electromagnetic beam can generate photo-induced or photo-acoustic cavitation effects in the fluid. The photo-acoustic waves can assist in dislodging and/or removing the foreign object12from the root canal15. In some embodiments, the localized heating can induce rotational fluid flow in the chamber6and/or tooth10that further enhances cleaning of the tooth10. The electromagnetic radiation from a radiation source (e.g., a laser) can be propagated to the chamber by an optical waveguide (e.g., an optical fiber), and dispersed into the fluid at a distal end of the waveguide (e.g., a shaped tip of the fiber, e.g., a conically-shaped tip). In other implementations, the radiation can be directed to the chamber by a beam scanning system.

The wavelength of the electromagnetic energy may be in a range that is strongly absorbed by water molecules. The wavelength may in a range from about 300 nm to about 3000 nm. In some embodiments, the wavelength is in a range from about 400 nm to about 700 nm, about 700 nm to about 1000 nm (e.g., 790 nm, 810 nm, 940 nm, or 980 nm), in a range from about 1 micron to about 3 microns (e.g., about 2.7 microns or 2.9 microns), or in a range from about 3 microns to about 30 microns (e.g., 9.4 microns or 10.6 microns). The electromagnetic energy can be in the ultraviolet, visible, near-infrared, mid-infrared, microwave, or longer wavelengths.

The electromagnetic energy can be pulsed or modulated (e.g., via a pulsed laser), for example with a repetition rate in a range from about 1 Hz to about 500 kHz. The pulse energy can be in a range from about 1 mJ to about 1000 mJ. The pulse width can be in a range from about 1 μs to about 500 μs, about 1 ms to about 500 ms, or some other range. In some cases, nanosecond pulsed lasers can be used with pulse rates in a range from about 100 ns to about 500 ns. The foregoing are non-limiting examples of radiation parameters, and other repetition rates, pulse widths, pulse energies, etc. can be used in other embodiments.

The laser can include one or more of a diode laser, a solid state laser, a fiber laser, an Er:YAG laser, an Er:YSGG laser, an Er,Cr:YAG laser, an Er,Cr:YSGG laser, a Ho:YAG laser, a Nd:YAG laser, a CTE:YAG laser, a CO2laser, or a Ti:Sapphire laser. In other embodiments, the source of electromagnetic radiation can include one or more light emitting diodes (LEDs). The electromagnetic radiation can be used to excite nanoparticles (e.g., light-absorbing gold nanorods or nanoshells) inside the treatment fluid, which may increase the efficiency of photo-induced cavitation in the fluid. The treatment fluid can include excitable functional groups (e.g., hydroxyl functional groups) that may be susceptible to excitation by the electromagnetic radiation and which may increase the efficiency of pressure wave generation (e.g., due to increased absorption of radiation). During some treatments, radiation having a first wavelength can be used (e.g., a wavelength strongly absorbed by the liquid, for instance water) followed by radiation having a second wavelength not equal to the first wavelength (e.g., a wavelength less strongly absorbed by water) but strongly absorbed by another element, e.g. dentin, or nanoparticles added to solution. For example, in some such treatments, the first wavelength may help create bubbles in the fluid, and the second wavelength may help disrupt the tissue.

In some implementations, electromagnetic energy can be added to other fluid motion generation modalities. For example, electromagnetic energy can be delivered to a chamber in which another pressure wave generator (e.g., a liquid jet) is used to generate the acoustic waves.

(4) Acoustic Energy

Acoustic energy (e.g., ultrasonic, sonic, audible, and/or lower frequencies) can be generated from electric energy transferred to, e.g., an ultrasound or other transducer or an ultrasonic tip (or file or needle) that creates acoustic waves in the treatment fluid. The ultrasonic or other type of acoustic transducer can comprise a piezoelectric crystal that physically oscillates in response to an electrical signal or a magnetostrictive element that converts electromagnetic energy into mechanical energy. The transducer can be disposed in the treatment fluid, for example, in the fluid inside the chamber. As explained herein, for example, ultrasonic or other acoustic devices used with the embodiments disclosed herein are preferably broadband and/or multi-frequency devices. For example, unlike the power spectra of the conventional ultrasonic transducer shown inFIG. 6B, ultrasonic or other acoustic devices used with the disclosed embodiments preferably have broadband characteristics similar to those of the power spectra ofFIGS. 6A and 6C(acoustic power of a liquid jet device).

(5) Further Properties of Some Pressure Wave Generators

A pressure wave generator64can be placed at a desired location with respect to the tooth10. The pressure wave generator64creates pressure waves within the fluid inside the tooth and/or the chamber6(the generation of acoustic waves may or may not create or cause cavitation) of the fluid platform61. The acoustic or pressure waves67propagate throughout the fluid inside the chamber6or the tooth, with the fluid in the chamber6or the tooth serving as a propagation medium for the pressure waves67. The pressure waves67can also propagate through tooth material (e.g., dentin). It is believed, although not required, that as a result of application of a sufficiently high-intensity acoustic wave, acoustic cavitation may occur. The collapse of cavitation bubbles may induce, cause, or be involved in a number of processes described herein such as, e.g., sonochemistry, tissue dissociation, tissue delamination, sonoporation, and/or removal of calcified structures. In some embodiments, the pressure wave generator can be configured such that the acoustic waves (and/or cavitation) do not substantially break down natural dentin in the tooth10. The acoustic wave field by itself or in addition to cavitation may be involved in one or more of the abovementioned processes to cause the foreign object12to move proximally.

In some implementations, the pressure wave generator64generates primary cavitation, which creates acoustic waves, which may in turn lead to secondary cavitation. The secondary cavitation may be weaker than the primary cavitation and may be non-inertial cavitation. In other implementations, the pressure wave generator64generates acoustic waves directly, which may lead to secondary cavitation.

The energy source that provides the energy for the pressure wave generator64can be located outside the handpiece, inside the handpiece, integrated with the handpiece, etc.

Additional details of fluid motion generators (e.g., which may comprise a pressure wave generator) that may be suitable for use with the embodiments disclosed herein may be found, e.g., in ¶¶[0191]-[0217], and various other portions of U.S. Patent Publication No. US 2012/0237893, published Sep. 20, 2012, which is incorporated by reference herein for all purposes.

Other pressure wave generators may be suitable for use with the disclosed embodiments. For example, a fluid inlet can be disposed at a distal portion of a handpiece and/or can be coupled to a fluid platform in some arrangements. The fluid inlet can be configured to create movement of the fluid in a chamber6, turbulence in the fluid in the chamber, fluid motion of the fluid in the chamber6and/or produce other dynamics in the fluid in the chamber6. For example, the fluid inlet can inject fluid into or on the tooth to be treated. In addition, mechanical stirrers and other devices can be used to enhance fluid motion and movement of the foreign object12(and/or cleaning). The fluid inlet can improve the circulation of the treatment fluid in a chamber, which can enhance the removal of the foreign object12and of unhealthy materials from the tooth10. For example, as explained herein, faster mechanisms of reactant delivery such as “macroscopic” liquid circulation may be advantageous in some of the embodiments disclosed herein.

In some embodiments, multiple pressure wave generators can be disposed in or on the chamber6or the tooth10. Each of the multiple pressure wave generators can be configured to propagate acoustic waves at a different frequency or range of frequencies. The multiple pressure wave generators can be activated simultaneously and/or sequentially in various arrangements.

III. Examples of Power Generated by Various Pressure Wave Generators

FIGS. 6A and 6Bare graphs that schematically illustrate possible examples of power that can be generated by different embodiments of the pressure wave generators disclosed herein. These graphs schematically show acoustic power (in arbitrary units) on the vertical axis as a function of acoustic frequency (in kHz) on the horizontal axis. The acoustic power in the tooth may influence, cause, or increase the strength of effects including, e.g., acoustic cavitation (e.g., cavitation bubble formation and collapse, microjet formation), acoustic streaming, microerosion, fluid agitation, fluid circulation and/or rotational motion, sonoporation, sonochemistry, and so forth, which may act to remove the foreign object12and/or to dissociate organic material in or on the tooth and effectively clean the undesirable materials, e.g., undesirable organic and/or inorganic materials and deposits. In various embodiments, the pressure wave generator can produce a pressure wave including acoustic power (at least) at frequencies above: about 1 Hz, about 0.5 kHz, about 1 kHz, about 10 kHz, about 20 kHz, about 50 kHz, about 100 kHz, or greater. The pressure wave can have acoustic power at other frequencies as well (e.g., at frequencies below the aforelisted frequencies).

The graph inFIG. 6Arepresents a schematic example of acoustic power generated by a liquid jet impacting a surface disposed within a chamber on or around the tooth that is substantially filled with liquid and by the interaction of the liquid jet with fluid in the chamber. This schematic example shows a broadband spectrum190of acoustic power with significant power extending from about 1 Hz to about 1000 kHz, including, e.g., significant power in a range of about 1 kHz to about 1000 kHz (e.g., the bandwidth can be about 1000 kHz). The bandwidth of the acoustic energy spectrum may, in some cases, be measured in terms of the 3-decibel (3-dB) bandwidth (e.g., the full-width at half-maximum or FWHM of the acoustic power spectrum). In various examples, a broadband acoustic power spectrum can include significant power in a bandwidth in a range from about 1 Hz to about 500 kHz, in a range from about 1 kHz to about 500 kHz, in a range from about 10 kHz to about 100 kHz, or some other range of frequencies. In some implementations, a broadband spectrum can include acoustic power above about 1 MHz. In some embodiments, the pressure wave generator can produce broadband acoustic power with peak power at about 10 kHz and a bandwidth of about 100 kHz. In various embodiments, the bandwidth of a broadband acoustic power spectrum is greater than about 10 kHz, greater than about 50 kHz, greater than about 100 kHz, greater than about 250 kHz, greater than about 500 kHz, greater than about 1 MHz, or some other value. In some foreign object removal methods, acoustic power between about 1 Hz and about 200 kHz, e.g., in a range of about 20 kHz to about 200 kHz may be particularly effective. The acoustic power can have substantial power at frequencies greater than about 1 kHz, greater than about 10 kHz, greater than about 100 kHz, or greater than about 500 kHz. Substantial power can include, for example, an amount of power that is greater than 10%, greater than 25%, greater than 35%, or greater than 50% of the total acoustic power (e.g., the acoustic power integrated over all frequencies). In some arrangements, the broadband spectrum190can include one or more peaks, e.g., peaks in the audible, ultrasonic, and/or megasonic frequency ranges.

The graph inFIG. 6Brepresents a schematic example of acoustic power generated by an ultrasonic transducer disposed in a chamber on or around the tooth that is substantially filled with liquid. This schematic example shows a relatively narrowband spectrum192of acoustic power with a highest peak192anear the fundamental frequency of about 30 kHz and also shows peaks192bnear the first few harmonic frequencies. The bandwidth of the acoustic power near the peak may be about 5 to 10 kHz, and can be seen to be much narrower than the bandwidth of the acoustic power schematically illustrated inFIG. 6A. In other embodiments, the bandwidth of the acoustic power can be about 1 kHz, about 5 kHz, about 10 kHz, about 20 kHz, about 50 kHz, about 100 kHz, or some other value. The acoustic power of the example spectrum192has most of its power at the fundamental frequency and first few harmonics, and therefore the ultrasonic transducer of this example may provide acoustic power at a relatively narrow range of frequencies (e.g., near the fundamental and harmonic frequencies). The acoustic power of the example spectrum190exhibits relatively broadband power (with a relatively high bandwidth compared to the spectrum192), and the example liquid jet can provide acoustic power at significantly more frequencies than the example ultrasonic transducer. For example, the relatively broadband power of the example spectrum190illustrates that the example jet device provides acoustic power at these multiple frequencies with energy sufficient to dislodge and move a foreign object12and/or to break the bonds between the decayed and healthy material so as to substantially remove the decayed material from the carious region.

It is believed, although not required, that pressure waves having broadband acoustic power (see, e.g., the example shown inFIG. 6A) can generate acoustic cavitation that is more effective at removing a foreign object12and at cleaning teeth (including cleaning, e.g., unhealthy materials in or on the tooth) than cavitation generated by pressure waves having a narrowband acoustic power spectrum (see, e.g., the example shown inFIG. 6B). For example, a broadband spectrum of acoustic power can produce a relatively broad range of bubble sizes in the cavitation cloud and on the surfaces on the tooth, and the implosion of these bubbles may be more effective at dislodging objects and/or disrupting tissue than bubbles having a narrow size range. Relatively broadband acoustic power may also allow acoustic energy to work on a range of length scales, e.g., from the cellular scale up to the tissue scale. Accordingly, pressure wave generators that produce a broadband acoustic power spectrum (e.g., some embodiments of a liquid jet) can be more effective at the removal of foreign objects and at tooth cleaning for some treatments than pressure wave generators that produce a narrowband acoustic power spectrum. In some embodiments, multiple narrowband pressure wave generators can be used to produce a relatively broad range of acoustic power. For example, multiple ultrasonic tips, each tuned to produce acoustic power at a different peak frequency, can be used. As used herein, broadband frequencies and broadband frequency spectrum is defined regardless of secondary effects such as harmonics of the main frequencies and regardless of any noise introduced by measurement or data processing (e.g., FFT); that is, these terms should be understood when only considering all main frequencies activated by the pressure wave generator.

FIG. 6Cis a graph of an acoustic power spectrum1445generated at multiple frequencies by the pressure wave generators disclosed herein. For example, the spectrum1445inFIG. 6Cis an example of acoustic power generated by a liquid jet impacting a surface disposed within a chamber on, in, or around the tooth that is substantially filled with liquid and by the interaction of the liquid jet with fluid in the chamber. The spectrum1445ofFIG. 6Crepresents acoustic power detected by a sensor spaced apart from the source of the acoustic energy, e.g., the pressure wave generator. The data was acquired inside an insulated water tank data when the distance between the power wave generator and the hydrophone (e.g., sensor) being about 8 inches. The vertical axis of the plot represents a measure of acoustic power: Log(Pacoustic2), referred to herein as “power units”. The units of Pacousticin the measurement were μPa (micro Pascal). Thus, it should be appreciated that the actual power at the source may be of a different magnitude because the sensor is spaced from the acoustic power generator. However, the general profile of the power spectrum at the source should be the same as the spectrum1445detected at the sensor and plotted inFIG. 6C. It should also be understood that, although the plot shows frequencies only up to 100 KHz, the power above 100 KHz was greater than zero—the data just was not plotted. It should further be noted that, as would be appreciated by one skilled in the art, the plot and the values would also depend on other parameters, such as, for example, the size and shape of the tank in which data was acquired, the insulation of the inner surface of the tank, the relative distance between the source (e.g., power wave generator), and the free water surface of the tank.

As shown inFIG. 6C, the spectrum1445can include acoustic power at multiple frequencies1447, e.g., multiple discrete frequencies. In particular, the spectrum1445illustrated inFIG. 6Cincludes acoustic power at frequencies in a range of about 1 Hz to about 100 KHz. The acoustic power can be in a range of about 10 power units to about 80 power units at these frequencies. In some arrangements, the acoustic power can be in a range of about 30 power units to about 75 power units at frequencies in a range of about 1 Hz to about 10 kHz. In some arrangements, the acoustic power can be in a range of about 10 power units to about 30 power units at frequencies in a range of about 1 KHz to about 100 kHz. In some embodiments, for example, the broadband frequency range of the pressure waves generated by the pressure wave generators disclosed herein can comprise a substantially white noise distribution of frequencies.

Pressure wave generators that generate acoustic power associated with the spectrum1445ofFIG. 6Ccan advantageously and surprisingly remove foreign objects12from the root canals15of teeth10, and can clean undesirable materials from teeth. For example, in each of the embodiments disclosed herein, the broadband energy of the pressure waves can deliver energy to the tooth10at multiple frequencies. Each frequency (or frequency range) can resonate with foreign objects12of a particular size and/or shape, and/or with root canals15having particular sizes and/or shapes. Thus, in the embodiments disclosed herein, for a foreign object12having a particular size and/or shape, the embodiments disclosed herein can deliver energy at one or more corresponding frequencies in the broad spectrum of delivered energy which can resonate with the object12to assist in dislodging or removing the object12from the root canal15. The delivered energy (and/or the spectrum of delivered energy) can be further adjusted by changing one or more parameters of the system1, such as pump pressure (e.g., by way of the user interface53and/or automatically based on feedback from the sensor). Such adjustment of the system parameters can assist in dislodging and/or removing foreign objects12having various different shapes and/or sizes. For example, in some procedures, if the foreign object12is not being effectively dislodged or removed, the clinician can adjust the system parameters to create different power spectra and/or fluid dynamics, which may assist in dislodging and/or removing the object12. In some embodiments, as shown inFIG. 6C, lower frequency cleaning phases can be activated at higher powers, and higher frequency cleaning phases can be activated at lower powers. In other embodiments, low frequency cleaning phases may be activated at relatively low powers, and high frequency cleaning phases may be activated at relatively high powers.

In the embodiments disclosed herein, treatment procedures can be activated to generate acoustic power at various frequency ranges. For example, some treatment phases may be activated at lower frequencies, and other treatment phases may be activated at higher frequencies. The pressure wave generators disclosed herein can be adapted to controllably generate acoustic power at any suitable frequencies1447of the spectrum1445. For example, the pressure wave generators disclosed herein can be adapted to generate power at multiple frequencies1447simultaneously, e.g., such that the delivered acoustic power in a particular treatment procedure can include a desired combination of individual frequencies. For example, in some procedures, power may be generated across the entire frequency spectrum1445. In some treatment phases, the pressure wave generator can deliver acoustic power at only relatively low frequencies, and in other treatment phases, the pressure wave generator can deliver power at only relatively high frequencies, as explained herein. Further, depending on the desired treatment procedure, the pressure wave generator can automatically or manually transition between frequencies1447according to a desired pattern, or can transition between frequencies1447randomly. In some arrangements, relatively low frequencies can be associated with large-scale bulk fluid movement, and relatively high frequencies can be associated with small-scale, high-energy oscillations.

Various treatment procedures may include any suitable number of treatment phases at various different frequencies. Furthermore, although various low- and high-frequency phases may be described above as occurring in a particular order, in other embodiments, the order of activating the low- and high-frequency phases, and/or any intermediate frequency phases, may be any suitable order.

As will be described below, the treatment fluid (and/or any of solutions added to the treatment fluid) can be degassed compared to normal liquids used in dental offices. For example, degassed distilled water can be used (with or without the addition of chemical agents or solutes).

A. Examples of Possible Effects of Dissolved Gases in the Treatment Fluid

In some procedures, the treatment fluid can include dissolved gases (e.g., air). For example, the fluids used in dental offices generally have a normal dissolved gas content (e.g., determined from the temperature and pressure of the fluid based on Henry's law). During various procedures using a pressure wave generator (including the removal of foreign objects12and/or cleaning procedures), the acoustic field of the pressure wave generator and/or the flow or circulation of fluids in the chamber can cause some of the dissolved gas to come out of solution and form bubbles.

The bubbles can block small passageways or cracks or surface irregularities in the tooth, and such blockages can act as if there were a “vapor lock” in the small passageways. In some such procedures, the presence of bubbles may at least partially block, impede, or redirect propagation of acoustic waves past the bubbles and may at least partially inhibit or prevent cleaning action from reaching, for example, unhealthy dental materials in tubules and small spaces of the tooth10. The bubbles may block fluid flow or circulation from reaching these difficult-to-reach, or otherwise small, regions, which may prevent or inhibit a treatment solution from reaching these areas of the tooth.

In certain procedures, cavitation is believed to play a role in removing foreign objects12from root canals15and in cleaning the tooth. Without wishing to be bound by any particular theory, the physical process of cavitation inception may be, in some ways, similar to boiling. One possible difference between cavitation and boiling is the thermodynamic paths that precede the formation of the vapor in the fluid. Boiling can occur when the local vapor pressure of the liquid rises above the local ambient pressure in the liquid, and sufficient energy is present to cause the phase change from liquid to a gas. It is believed that cavitation inception can occur when the local ambient pressure in the liquid decreases sufficiently below the saturated vapor pressure, which has a value given in part by the tensile strength of the liquid at the local temperature. Therefore, it is believed, although not required, that cavitation inception is not determined by the vapor pressure, but instead by the pressure of the largest nuclei, or by the difference between the vapor pressure and the pressure of the largest nuclei. As such, it is believed that subjecting a fluid to a pressure slightly lower than the vapor pressure generally does not cause cavitation inception. However, the solubility of a gas in a liquid is proportional to pressure; therefore lowering the pressure may tend to cause some of the dissolved gas inside the fluid to be released in the form of gas bubbles that are relatively large compared to the size of bubbles formed at cavitation inception. These relatively large gas bubbles may be misinterpreted as being vapor cavitation bubbles, and their presence in a fluid may have been mistakenly described in certain reports in the literature as being caused by cavitation, when cavitation may not have been present.

In the last stage of collapse of vapor cavitation bubbles, the velocity of the bubble wall may even exceed the speed of sound and create strong shock waves inside the fluid. The vapor cavitation bubble may also contain some amount of gas, which may act as a buffer and slow down the rate of collapse and reduce the intensity of the shockwaves. Therefore, in certain procedures that utilize cavitation bubbles for foreign object removal or tooth cleaning, it may be advantageous to reduce the amount of the dissolved air in the fluid to prevent such losses.

The presence of bubbles that have come out of solution from the treatment fluid may lead to other disadvantages during certain procedures (including the removal of foreign objects12). For example, if the pressure wave generator produces cavitation, the agitation (e.g. pressure drop) used to induce the cavitation may cause the release of the dissolved air content before the water molecules have a chance to form a cavitation bubble. The already-formed gas bubble may act as a nucleation site for the water molecules during the phase change (which was intended to form a cavitation bubble). When the agitation is over, the cavitation bubble is expected to collapse and create pressure waves. However, cavitation bubble collapse might happen with reduced efficiency, because the gas-filled bubble may not collapse and may instead remain as a bubble. Thus, the presence of gas in the treatment fluid may reduce the effectiveness of the cavitation process as many of the cavitation bubbles may be wasted by merging with gas-filled bubbles. Additionally, bubbles in the fluid may act as a cushion to damp pressure waves propagating in the region of the fluid comprising the bubbles, which may disrupt effective propagation of the pressure waves past the bubbles. Some bubbles may either form on or between tooth surfaces, or be transferred there by the flow or circulation of fluid in the tooth. The bubbles may be hard to remove due to relatively high surface tension forces. This may result in blocking the transfer of chemicals and/or pressure waves into the irregular surfaces and small spaces in and between teeth, and therefore may disrupt or reduce the efficacy of the object removal or cleaning treatment.

B. Examples of Degassed Treatment Fluids

Accordingly, it may be advantageous in some systems and methods to use a degassed fluid, which can inhibit, reduce, or prevent bubbles from coming out of solution during treatments (including the removal of foreign objects12) as compared to systems and methods that use normal (e.g., non-degassed) fluids. In dental procedures in which the treatment fluid has a reduced gas content (compared with the normal fluids) tooth surfaces or tiny spaces in the tooth may be free of bubbles that have come out of solution. Acoustic waves generated by the pressure wave generator can propagate through the degassed fluid to agitate the foreign object during object removal procedures, and to reach and clean the surfaces, cracks, and tooth spaces and cavities during cleaning procedures. In some procedures, the degassed fluid can be able to penetrate spaces as small as about 500 microns, 200 microns, 100 microns, 10 microns, 5 microns, 1 micron, or smaller, because the degassed fluid is sufficiently gas-free that bubbles are inhibited from coming out of solution and blocking these spaces (as compared to use of fluids with normal dissolved gas content).

For example, in some systems and methods, the degassed fluid can have a dissolved gas content that is reduced when compared to the “normal” gas content of water. For example, according to Henry's law, the “normal” amount of dissolved air in water (at 25 C and 1 atmosphere) is about 23 mg/L, which includes about 9 mg/L of dissolved oxygen and about 14 mg/L of dissolved nitrogen. In some embodiments, the degassed fluid has a dissolved gas content that is reduced to approximately 10%-40% of its “normal” amount as delivered from a source of fluid (e.g., before degassing). In other embodiments, the dissolved gas content of the degassed fluid can be reduced to approximately 5%-50% or 1%-70% of the normal gas content of the fluid. In some treatments, the dissolved gas content can be less than about 70%, less than about 50%, less than about 40%, less than about 30%, less than about 20%, less than about 10%, less than about 5%, or less than about 1% of the normal gas amount.

In some embodiments, the amount of dissolved gas in the degassed fluid can be measured in terms of the amount of dissolved oxygen (rather than the amount of dissolved air), because the amount of dissolved oxygen can be more readily measured (e.g., via titration or optical or electrochemical sensors) than the amount of dissolved air in the fluid. Thus, a measurement of dissolved oxygen in the fluid can serve as a proxy for the amount of dissolved air in the fluid. In some such embodiments, the amount of dissolved oxygen in the degassed fluid can be in a range from about 1 mg/L to about 3 mg/L, in a range from about 0.5 mg/L to about 7 mg/L, or some other range. The amount of dissolved oxygen in the degassed fluid can be less than about 7 mg/L, less than about 6 mg/L, less than about 5 mg/L, less than about 4 mg/L, less than about 3 mg/L, less than about 2 mg/L, or less than about 1 mg/L.

In some embodiments, the amount of dissolved gas in the degassed fluid can be in a range from about 2 mg/L to about 20 mg/L, in a range from about 1 mg/L to about 12 mg/L, or some other range. The amount of dissolved gas in the degassed fluid can be less than about 20 mg/L, less than about 18 mg/L, less than about 15 mg/L, less than about 12 mg/L, less than about 10 mg/L, less than about 8 mg/L, less than about 6 mg/L, less than about 4 mg/L, or less than about 2 mg/L.

In other embodiments, the amount of dissolved gas can be measured in terms of air or oxygen percentage per unit volume. For example, the amount of dissolved oxygen (or dissolved air) can be less than about 5% by volume, less than about 1% by volume, less than about 0.5% by volume, or less than about 0.1% by volume.

The amount of dissolved gas in a liquid can be measured in terms of a physical property such as, e.g., fluid viscosity or surface tension. For example, degassing water tends to increase its surface tension. The surface tension of non-degassed water is about 72 mN/m at 20° C. In some embodiments, the surface tension of degassed water can be about 1%, 5%, or 10% greater than non-degassed water.

In some treatment methods, one or more secondary fluids can be added to a primary degassed fluid (e.g., an antiseptic solution can be added to degassed distilled water). In some such methods, the secondary solution(s) can be degassed before being added to the primary degassed fluid. In other applications, the primary degassed fluid can be sufficiently degassed such that inclusion of the secondary fluids (which can have normal dissolved gas content) does not increase the gas content of the combined fluids above what is desired for a particular dental treatment.

In various implementations, the treatment fluid can be provided as degassed liquid inside sealed bags or containers. The fluid can be degassed in a separate setup in the operatory before being added to a fluid reservoir. In an example of an “in-line” implementation, the fluid can be degassed as it flows through the system, for example, by passing the fluid through a degassing unit attached along a fluid line (e.g., the fluid inlet). Examples of degassing units that can be used in various embodiments include: a Liqui-Cel® MiniModule® Membrane Contactor (e.g., models 1.7×5.5 or 1.7×8.75) available from Membrana-Charlotte (Charlotte, N.C.); a PermSelect® silicone membrane module (e.g., model PDMSXA-2500) available from MedArray, Inc. (Ann Arbor, Mich.); and a FiberFlo® hollow fiber cartridge filter (0.03 micron absolute) available from Mar Cor Purification (Skippack, Pa.). The degassing can be done using any of the following degassing techniques or combinations of thereof: heating, helium sparging, vacuum degassing, filtering, freeze-pump-thawing, and sonication.

In some embodiments, degassing the fluid can include de-bubbling the fluid to remove any small gas bubbles that form or may be present in the fluid. De-bubbling can be provided by filtering the fluid. In some embodiments, the fluid may not be degassed (e.g., removing gas dissolved at the molecular level), but can be passed through a de-bubbler to remove the small gas bubbles from the fluid.

In some embodiments, a degassing system can include a dissolved gas sensor to determine whether the treatment fluid is sufficiently degassed for a particular treatment. A dissolved gas sensor can be disposed downstream of a mixing system and used to determine whether mixing of solutes has increased the dissolved gas content of the treatment fluid after addition of solutes, if any. A solute source can include a dissolved gas sensor. For example, a dissolved gas sensor can measure the amount of dissolved oxygen in the fluid as a proxy for the total amount of dissolved gas in the fluid, since dissolved oxygen can be measured more readily than dissolved gas (e.g., nitrogen or helium). Dissolved gas content can be inferred from dissolved oxygen content based at least partly on the ratio of oxygen to total gas in air (e.g., oxygen is about 21% of air by volume). Dissolved gas sensors can include electrochemical sensors, optical sensors, or sensors that perform a dissolved gas analysis. Examples of dissolved gas sensors that can be used with embodiments of various systems disclosed herein include a Pro-Oceanus GTD-Pro or HGTD dissolved gas sensor available from Pro-Oceanus Systems Inc. (Nova Scotia, Canada) and a D-Opto dissolved oxygen sensor available from Zebra-Tech Ltd. (Nelson, New Zealand). In some implementations, a sample of the treatment can be obtained and gases in the sample can be extracted using a vacuum unit. The extracted gases can be analyzed using a gas chromatograph to determine dissolved gas content of the fluid (and composition of the gases in some cases).

Accordingly, fluid delivered to the tooth from a fluid inlet and/or the fluid used to generate the jet in a liquid jet device can comprise a degassed fluid that has a dissolved gas content less than normal fluid. The degassed fluid can be used, for example, to generate the high-velocity liquid beam for generating acoustic waves, to substantially fill or irrigate a chamber, to provide a propagation medium for acoustic waves, to inhibit formation of air (or gas) bubbles in the chamber, and/or to provide flow of the degassed fluid into small spaces in the tooth (e.g., cracks, irregular surfaces, tubules, etc.), which may enhance the removal of foreign objects12and/or cleaning of the tooth. In embodiments utilizing a liquid jet, use of a degassed fluid can inhibit bubbles from forming in the jet due to the pressure drop at a nozzle orifice where the liquid jet is formed.

Thus, examples of methods for dental and/or endodontic treatment comprise flowing a degassed fluid onto a tooth or tooth surface or into a chamber. The degassed fluid can comprise a tissue dissolving agent and/or a decalcifying agent. The degassed fluid can have a dissolved oxygen content less than about 9 mg/L, less than about 7 mg/L, less than about 5 mg/L, less than about 3 mg/L, less than about 1 mg/L, or some other value. A fluid for treatment can comprise a degassed fluid with a dissolved oxygen content less than about 9 mg/L, less than about 7 mg/L, less than about 5 mg/L, less than about 3 mg/L, less than about 1 mg/L, or some other value. The fluid can comprise a tissue dissolving agent and/or a decalcifying agent. For example, the degassed fluid can comprise an aqueous solution of less than about 6% by volume of a tissue dissolving agent and/or less than about 20% by volume of a decalcifying agent.

Reference throughout this specification to “some embodiments” or “an embodiment” means that a particular feature, structure, element, act, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in some embodiments” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment and may refer to one or more of the same or different embodiments. Furthermore, the particular features, structures, elements, acts, or characteristics may be combined in any suitable manner (including differently than shown or described) in other embodiments. Further, in various embodiments, features, structures, elements, acts, or characteristics can be combined, merged, rearranged, reordered, or left out altogether. Thus, no single feature, structure, element, act, or characteristic or group of features, structures, elements, acts, or characteristics is necessary or required for each embodiment. All possible combinations and subcombinations are intended to fall within the scope of this disclosure.

As used in this application, the terms “comprising,” “including,” “having,” and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list.

Similarly, it should be appreciated that in the above description of embodiments, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that any claim require more features than are expressly recited in that claim. Rather, inventive aspects lie in a combination of fewer than all features of any single foregoing disclosed embodiment.

The foregoing description sets forth various example embodiments and other illustrative, but non-limiting, embodiments of the inventions disclosed herein. The description provides details regarding combinations, modes, and uses of the disclosed inventions. Other variations, combinations, modifications, equivalents, modes, uses, implementations, and/or applications of the disclosed features and aspects of the embodiments are also within the scope of this disclosure, including those that become apparent to those of skill in the art upon reading this specification. Additionally, certain objects and advantages of the inventions are described herein. It is to be understood that not necessarily all such objects or advantages may be achieved in any particular embodiment. Thus, for example, those skilled in the art will recognize that the inventions may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein. Also, in any method or process disclosed herein, the acts or operations making up the method or process may be performed in any suitable sequence and are not necessarily limited to any particular disclosed sequence.