Patent Grant
7607972
The present invention relates generally to the field of devices for propelling abrasive powder with intent to etch the surface of a target material. More specifically, the present invention relates to a micro-abrasive blasting device powered by a pressurized-gas source for use with dental procedures.
Abrasive blasting devices operate on the physical property that gas at a higher pressure flows towards and into gas at lower pressure. When abrasive powder is mixed with gas at higher pressure, the gas carries the abrasive powder as the gas accelerates and flows to the lower pressure. As the gas and abrasive powder blast the target material at high speed, the impact of the particles removes layers of the target material.
In dentistry this technology is known as micro-abrasion and is used to achieve a variety of goals—such as to remove foreign material or to dull a shiny surface, roughen or etch the surface to enhance bonding quality and to remove decay by drilling and cutting tooth structure.
A search of the prior art did not disclose any patents that possess the novelty of the instant invention; however the following U.S. patents are considered related:
Air abrasion devices date back decades with patented inventions by pioneers such as Ziegler U.S. Pat. No. 2,612,732, Crow U.S. Pat. No. 2,725,684, Schachter U.S. Pat. No. 3,626,841 and Paache U.S. Pat. No. 2,441,441.
Over the years two main approaches to air abrasion devices developed with Ziegler and Schechter following one approach and Crowe and Passche following another. One approach has been to provide a stationary mixing apparatus for generating the abrasive laden air stream and delivering the abrasive laden air stream through an extended hand-piece for directing the stream onto the target surface. Another approach has been to integrate the mixing apparatus into the hand-held device.
The first approach facilitates more complex mechanisms and many operational options since the size and weight of the device are of no concern. Because the extended hand-piece delivers the abrasive laden air stream independent of the mixing operation, the hand-piece can be held at any orientation during operation. Deardon et al. U.S. Pat. No. 6,083,001 discloses a dental air abrasion system in which the flow of the particles is electronically controlled by pressure differentials. Rainey U.S. Pat. No. 6,093,021 discloses an automated control system which utilizes a gas stream mounted particulate sensor to regulate fluid flow rates into and around the ultrasonically agitated mixing chamber in order to accurately maintain the abrasive concentration in the air stream. Various methods for reducing the overspray of the abrasive have also been developed for these devices. Ho U.S. Pat. No. 5,356,292, Coston U.S. Pat. No. 5,197,876, and Burns et al. U.S. Pat. No. 6,024,566 disclose add-on splatter guard and collector attachments to air abrasion devices.
In the second approach, the size, weight, and ergonomic shape of the device are significant factors. Herald et al. U.S. Pat. No. 5,199,299 and Burns et al. U.S. Pat. No. 6,439,966 disclose innovative hand-holdable air abrasion devices which mount the mixing apparatus into the hand-piece. The drawback of this approach is that the operation of these devices is limited by the orientation of the mixing chamber.
An adjunct to the second approach has been the concept of simple self-contained air abrasion devices—such as Hertz U.S. Pat. No. 5,839,946 (and its derivative patents U.S. Pat. Nos. 6,287,180, 6,951,505, and Granted application Ser. No. 09/939,865), Groman U.S. Pat. No. 6,398,628 (and its derivative patents U.S. Pat. No. 6,347,984 and Pending application Ser. No. 10/144/228), Schur et al. U.S. Pat. No. 6,004,191, and Trafton et al. U.S. Pat. No. 6,354,924. These devices rely on the air stream to perturb the abrasive and generate the mixing action based on Stark et al. U.S. Pat. No. 4,475,370 fixed air abrasion device for treating dental castings.
Merging of Stark's blow-through mixing method into the hand-piece so the mixing chamber is held between the user's fingers has taken air abrasion art to a new level. Because of their simplified structures, simple self-contained air abrasion devices tend to be less expensive to manufacture and can therefore be marketed to the user as disposable instruments.
With increased emphasis in Medical, Pharmaceutical, Cosmetic and Dental applications on reduced cross-patient contamination, there has been a significant drive towards single usage disposable packaging and devices. With advances in materials and fabrication technologies the cost of these devices has been significantly reduced. Dougherty U.S. Pat. No. 4,391,590 discloses a syringe and stopper like cartridge device for dispensing material while Hertz U.S. Pat. No. 5,839,946 patent discloses the formulation an air abrasion instrument from a syringe and stopper type structure. Both innovations capitalize on the lower cost of fabrication and the well established production methods of a syringe and stopper configuration.
Simple self-contained prior art air abrasion devices support an elongated cylindrical chamber with an inlet conduit for delivering the air into the mixing chamber and a discharge conduit for carrying the air-abrasive mixture out of the mixing chamber. The mixing chambers are utilized as a reservoir for storing the abrasive powder. Once the reservoir is depleted of abrasive material, the devices are discarded and therefore function as disposable instruments which do not require sterilization post intra-oral use.
To prevent the abrasive material from escaping the mixing chamber or becoming contaminated prior to use, simple self-contained prior art air abrasion devices add additional components which seal the inlet and outlet ports and conduits. While the Hertz U.S. Pat. No. 5,839,946, and Schur et al. U.S. Pat. No. 6,004,191 devices include passive caps which must be removed prior to using the instrument, Hetrz U.S. Pat. Nos. 6,951,505 and 6,287,180, and Groman U.S. Pat. Nos. 6,398,628 and 6,347,984 add functional components which actively prevent the abrasive from exiting the mixing chamber. Groman U.S. Pat. No. 6,398,628 has a filter that prevents the abrasive from exiting the device's inlet port and a movable discharge conduit which prevents abrasive material from exiting the mixing chamber when the discharge conduit inlet port abuts the side wall of the mixing chamber. Groman pending application Ser. No. 10/144,228 support a deformable gasket at the discharge port internal to the mixing chamber which opens when flow is present. Hertz U.S. Pat. No. 6,951,505 has a deformable seal at the inlet port external to the mixing chamber which functions as a check-valve that allows the pressurized-gas to enter the instrument but prevents abrasive from exiting the instrument. Groman U.S. Pat. No. 6,398,628 discloses a deformable and movable cap configurations which block both the delivery conduit inlet and discharge conduit outlet prior to use.
Another disposable delivery method disclosed by Zhang et al. U.S. Pat. No. 6,343,717 attempts to address the containment of stored material utilizing a pipette structure. A typical pipette consists of a slender pipe or tube that is used to transfer or measure small quantities of material from one location to another. The most common type of pipette consists of a small tube that widens into a bulb at the middle.
Zhang et al. pipette structure is made of a rigid or resilient material that is pre-filled with a pharmaceutical or cosmetic product and is used once and then discarded. Zhang et al. discloses a plurality of ways by which the disposable pipette can be sealed to contain the material and then unsealed by the user prior to use for dispensing the stored material. According to Zhang's et al. invention the majority of material is retained within the bulb section of the pipette, but Zhang's et al. sealing methods permit the contained material to migrate into the top and bottom tube sections. Although Zhang's et al. use of a pipette structure leads to a very cost effective means of delivering the contained material, Zhang's et al. sealing methods are not compatible with the needs of air abrasion devices.
Pressurized air stream is delivered to the simple self-contained air abrasion devices of Hertz, Groman, Schur, and Trafton via custom connectors which engage the device externally and to form a seal with the device body to deliver the pressurized air to the mixing chamber delivery port. The connectors are designed to supply clean dry air in order to maintain the abrasive powder dry, since any moisture causes clumping of the abrasive material and therefore the malfunction of the device. The dry air is required because the gas delivery conduit leads directly into the mixing chamber; therefore any liquid present at the entry to the device gets trapped in the mixing chamber. Hertz et al. U.S. Pat. No. 6,293,856 discloses a connector with additional conduits for carrying other types of fluids passively through the mixing chamber. This configuration requires a very complex connector to assure the separation of the fluids delivered to the air abrasion instrument without contaminating the mixing chamber. Custom connectors which supply dry air add to the installation cost and complexity of these disposable devices. And because they attach to the body of the devices, these connectors are typically very bulky.
Referring to
In their reduction to practice, both the Schur and Groman devices require the user to maintain the orientation of the device so the mixing chamber points downward. The attached user instructions for the Schur and Groman devices outline the specific user instructions cautioning the user about mis-orienting the mixing chamber. To compensate for his shortcoming, the marketed Groman instrument provides a finger bendable discharge conduit. The marketed Schur device provides a bending tool, so the user is able to form the delivery conduit to reach upper surfaces while maintaining the proper orientation of the mixing chamber.
Referring to
The invention disclosed herein solves the following shortcomings with the prior art simple self-contained air abrasion devices:
In addition, this invention teaches a new innovative method for constructing the air abrasion device out of a continuous tubing formed into a disposable pipette structure.
Accordingly, several objects and advantages of the present invention are to:
Still another object of the invention is that the material in the bulb of the pre-filled pipette is protected from contamination or spillage by the discharge conduit.
Various other objects, advantages, and features of the invention will become apparent to those skilled in the art from the following discussion taken in conjunction with the following drawings, where closely related figures have the same number but different alphabetic suffixes:
As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure.
Reference is now made to the drawings, wherein like characteristics and features of the present invention shown in the various figures are designated by the same reference numerals.
Referring to
Delivery conduit 30 comprises a delivery conduit external section 32 external to mixing chamber 23 and a delivery conduit internal section 34 internal to mixing chamber 23 and a connecting delivery conduit tapered section 33; external section 32 of delivery conduit 30 is preferably straight and preferably supports an outer and inner diameter that fits into standard tube and hose connectors such as push-in or push-on connector types; internal section 34 of delivery conduit 30 preferably supports an inner diameter that is equivalent to the outer diameter of discharge conduit inlet 12.
Referring to
Referring to
Referring to
Referring to
Micro-abrasive blasting device 75 is comprised of a pipette structure 80 which consists of three sections, a hollow bulb section forming a mixing chamber 23; a open ended hollow tubular delivery conduit 30 section smaller in diameter and contiguous with the bulb section at inlet port 27, for delivery of pressurized-gas; a hollow tubular discharge port 29 section smaller in diameter and contiguous with the bulb section, for discharging abrasive laden gas stream; a discharge conduit 10 in fluid communications with discharge port 29, and extending from a discharge conduit inlet 12 internal to mixing chamber 23 to a discharge conduit outlet 14 external to mixing chamber 23; a particulate matter 50 is disposed within mixing chamber 23. Preferably, delivery conduit 30 section extends from a delivery conduit inlet 35 through a external section 32 and a tapered section 33 to form a delivery conduit outlet 37 and a inlet port 27.
The outer and/or inner diameter of delivery conduit external section 32 is preferably selected to fit standard tube or hose fittings, while the inner diameters of inlet port 27 and discharge port 29 preferably support an inner diameter that is equivalent to or less than the outer diameter of discharge conduit 10. Design selections of these diameters may eliminate or reverse the gradient of delivery conduit tapered section 33, rendering delivery conduit 30 a straight tube. The diameter of hollow resilient bulb mixing chamber 23 is preferably selected to support the appropriate quantity of particulate matter 50 to at least perform one dental procedure.
Pipette structure 80 may be formed via blow-molding and/or tube swaging techniques, or other thermo-forming processes. These methods would typically require that one of the ends of the tubular pipette structure 80 be sealed in order to entrap pressurized-gas for forming the component during the blow-molding process. The sealed end may be formed at the delivery conduit inlet 35 of delivery conduit 30 section or at the tip of discharge port 29 section. The sealed end may be trimmed off during the assembly process of micro-abrasive blasting device 75 or just punctured or cut to permit air flow into micro-abrasive blasting device 75 when mounted onto a pressurized-gas connector. Additionally, the pressurized-gas connector could support cutting or puncturing means for breaking the blow-molded seal when delivery conduit 30 is mounted on the pressurized-gas connector.
Referring to
Referring to
Referring to
Referring to
Referring to
Referring to
Referring to
Referring to
Referring to
Further Enhancements to Preferred Embodiments
Referring to
Referring to
Preferably, protective nozzle guard 85 is removed prior to use, by pulling protective nozzle guard 85 coaxially to discharge conduit 10, thereby fully exposing discharge conduit 10. Preferably, perforation to pipette structure 80 is provided at nozzle guard separation point 87 as to weaken pipette structure 80 at nozzle guard separation point 87. Pulling on protective nozzle guard 85 coaxially to discharge conduit 10, causes pipette structure 80 to separate at nozzle guard separation point 87 allowing the removal of protective nozzle guard 85 to expose discharge conduit 10.
Referring to
Preferably, perforation to pipette structure 80 is provided at particle deflector separation point 93 as to weaken pipette structure 80 at particle deflector separation point 93. Pulling particle deflector 90 coaxially to discharge conduit 10, separates particle deflector 90 at particle deflector separation point 93 to permit the movement of particle deflector 90 along discharge conduit 10. Preferably particle deflector 90 is positioned near discharge conduit outlet 14 as to deflect particulate matter 50 ricocheting off the target surface during use.
Of course, pipette structure 80 may be constructed to include both protective nozzle guard 85 and particle deflector 90.
Mixing Method
Referring to
Therefore, the expansion and contraction of the gas-stream across separation gap 45 is accompanied by a localized pressure gradient 48 at separation gap 45. Pressure gradient 48 across separation gap 45 within mixing chamber 23 agitates particulate matter 50 causing particulate matter 50 to aerate. The aerated particulate matter 50 particles are pulled into the gas-stream at separation gap 45, generating an abrasive laden gas stream into discharge conduit inlet 12 and out of discharge conduit outlet 14. Because pressure gradient 48 across separation gap 45 is independent of mixing chamber 23 orientations, agitation also is independent of the orientation of mixing chamber 23.
This mixing method is independent of the mixing chamber shape as long as the mixing chamber 23 is wider than the delivery conduit outlet 37 and discharge conduit inlet 12. In the absence of delivery conduit outlet 37 where delivery conduit 30 terminates at inlet port 27, this innovative mixing method still applies as pressure gradient 48 is formed across separation gap 45.
Since separation gap 45 controls the rapidness by which the gas-stream expands and contracts, the distance of separation gap 45 controls the agitation rate of particulate matter 50 within mixing chamber 23. Therefore, the quantity of particulate matter 50 introduced into the gas-steam is selectable by the position of discharge conduit inlet 12 with respect to delivery conduit outlet 37 or inlet port 27.
From the description above, the following advantages of the present invention become evident:
While the invention has been described, disclosed, illustrated and shown in various terms or certain embodiments or modifications which it has assumed in practice, the scope of the invention is not intended to be, nor should it be deemed to be, limited thereby and such other modifications or embodiments as may be suggested by the teachings herein are particularly reserved especially as they fall within the breadth and scope of the claims here appended.
The present invention accomplishes the above-stated objectives, as well as others, as may be determined by a fair reading and interpretation of the entire specification.
Accordingly, the reader will see that the present invention is a micro-abrasive blasting device with reduced components, simplified construction, enhanced mixing methodology, and mountable to handheld gas supply connector.
Furthermore, the present invention has the additional advantages in that
Thus the scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the examples given.
| Number | Name | Date | Kind |
|---|---|---|---|
| 2441441 | Paasche | Sep 1948 | A |
| 2612732 | Ziegler | Oct 1952 | A |
| 2725684 | Crowe | Dec 1955 | A |
| 3626841 | Schachter | Dec 1971 | A |
| 4391590 | Dougherty | Jul 1983 | A |
| 4475370 | Stark et al. | Oct 1984 | A |
| 5197876 | Coston | Mar 1993 | A |
| 5199229 | Herold et al. | Apr 1993 | A |
| 5356292 | Ho | Oct 1994 | A |
| 5839946 | Hertz | Nov 1998 | A |
| 6004191 | Schur et al. | Dec 1999 | A |
| 6024566 | Burns et al. | Feb 2000 | A |
| 6083001 | Deardon et al. | Jul 2000 | A |
| 6093021 | Rainey | Jul 2000 | A |
| 6287180 | Hertz | Sep 2001 | B1 |
| 6293856 | Hertz et al. | Sep 2001 | B1 |
| 6343717 | Zhang et al. | Feb 2002 | B1 |
| 6347984 | Groman | Feb 2002 | B1 |
| 6354924 | Trafton et al. | Mar 2002 | B1 |
| 6398628 | Groman | Jun 2002 | B1 |
| 6439966 | Burns et al. | Aug 2002 | B2 |
| 6951505 | Hertz | Oct 2005 | B2 |
| Number | Date | Country | |
|---|---|---|---|
| 20070287126 A1 | Dec 2007 | US |
