Dentistry – Apparatus – Having intra-oral dispensing means
Reexamination Certificate
1999-10-15
2001-10-30
Lewis, Ralph A. (Department: 3732)
Dentistry
Apparatus
Having intra-oral dispensing means
Reexamination Certificate
active
06309217
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to dental abrasion systems and techniques and more particularly to the control of airborne abrasion materials by way of fluid streams, such as for example a water-aerosol spray.
BACKGROUND OF THE INVENTION
The conventional technique for repairing or otherwise treating teeth in dental procedures such as the removal of caries or in the manufacture/repair of dental prosthetic (eg crowns, dentures) typically involve the use of rotary drills. These drills perform at preset speeds, typically “high or “low”. As a result, these instruments lack fine control and are imprecise. Furthermore, the drilled surfaces are relatively smooth and are generally not ideal adhesive surfaces for the metals, porcelain, acrylics and/or composites routinely used in dental practice.
As an alternative, the use of air abrasion in micro-dentistry (AAMD) is attractive Its current but limited use extends to both intra (ie. removal of caries) and extraoral (ie dental prosthetic) applications. A major advantage of AAMD over conventional rotary drills is that it is more precise and affords the user much more control in the aforementioned intra and extraoral applications. Additionally, AAMD typically results in augmented and eroded surface areas which are more amenable to adhesion to metals, porcelain, acrylics and composites. This latter adhesion can be increased by 80% when compared with surfaces resulting from conventional drilling
Notwithstanding the apparent advantages of AAMD over conventional rotary drilling, the use of the former has been limited by technical and health-related difficulties. Conventional AAMD devices are not capable of controlling emissions of both the abrasive dust and airborne abraded dental amalgam material, inside the mouth of the patient and outside to the dental operatory. The abrasive material typically includes an aluminum oxide powder of 27.5 to 50.0 microns in particle size and therefore travels easily in ambient air as dust. Its aluminum content makes it a toxicological risk for Alzheimer's Disease. Meanwhile, the abraded dental amalgam can have toxic constituents such as mercury from old dental fillings. This contamination of dental operatories persists in current applications despite the use of high efficiency particulate air (HEPA) vacuum systems. Furthermore, extensive use of intraoral latex rubber dams are also necessary to aid in the prevention of inhaling the respirable aluminum powder by patients. The use of these latter latex rubber dams is also problematic in light of the possibility of inducing latex-associated asthmatic or respiratory type reactions. As neither prevention technique is particularly efficient or effective, the continuance of exposure to the abrasive dust and abraded dental amalgam and the attendant potential for health complication(s) is of concern to both patients and dental professionals.
In light of this prior art, the development of an abrasion system that provides improved dust suppression would be considered revolutionary within the field of micro-dentry As such, overcoming the problem of respirable dust would create better visibility, healthier conditions, make practical extra and intra-oral usage and eliminate the need for costly high efficiency particulate air (HEPA) filter vacuum units.
It is therefore an object of the present invention to provide a novel dental abrasion system
It is also an object of the present invention to provide novel techniques for dental abrasion.
SUMMARY OF THE INVENTION
In one aspect of the present invention, there is provided a dental abrasion device comprising first delivery means to deliver pressurized abrasive material to a tooth region and second delivery means to deliver a supply of pressurized fluid near said tooth region under conditions sufficient to suppress airborne emissions of said abrasive material from said tooth region.
Preferably, the first delivery means includes a head and a nozzle mounted on the head with a first conduit therein to receive the abrasive material. The second delivery means includes a plurality of second conduits near the first conduit to receive the pressurized fluid The second conduits are arranged so that the fluid leaving them generates, for example, a curtain-like stream toward the tooth region In other words, the individual fluid streams leaving the second conduits converge to a hollow substantially continuous stream to define an inner region Conveniently, the first conduit may be arranged to deliver the abrasive material to the inner region The pressure and content of the fluid stream can thus retard or, in some cases prevent, airborne abrasive material from breaking through the curtain, either causing it to be entrained in the fluid or to be repelled back into the inner region.
The pressurized fluid may be provided in a variety of forms including a mixture of water and a gas such as air, or other suitable gases such as nontoxic or inert gases, for example nitrogen or carbon dioxide. In the case of air, the fluid may include 10 to 75 percent water by volume, or more preferably 25 to 65 percent water by volume. The pressurized fluid itself may be dispensed, if desired, at pressures ranging from 5 to 75 psi, for example.
In another aspect of the present invention, there is provided a dental abrasion device comprising first delivery means to deliver abrasive material to a tooth region and second delivery means to deliver a supply of pressurized fluid near said tooth region under suitable conditions for retarding the passage of airborne abrasive material there through.
Preferably, the pressurized fluid forms a curtain of fluid around the tooth region More preferably, the curtain completely encircles the tooth region
In still another aspect of the present invention, there is provided a dental abrasion system operable to deliver an abrasive material stream to a tooth region and a fluid stream near said tooth region under conditions sufficient to suppress airborne abrasive material emissions from said tooth region
In still another aspect of the present invention, there is provided a method of abrading a tooth, comprising the steps of delivering first supply of abrasive material to a tooth region in a patient's oral cavity and delivering a second supply of fluid near said tooth region, wherein said fluid has sufficient volume and pressure to form a barrier to airborne abrasive material between said tooth region and said oral cavity
Thus, the invention provides a dental abrading tool that utilizes abrasive dust as the abrasion material, and which provides effective dust suppression by the use of a fluid stream, such as for example a water-aerosol spray. In this example, the tool emits a stream of the abrasive material as well as the water-aerosol spray, the latter under conditions sufficient to minimize the amount of dust leaving the tooth region and thus control widespread contamination by the airborne abrasive material.
For example, the dental abrading tool may be hand controlled, by way of “push botton” or “touch sensory” controls. Furthermore, the controls may be such that the fluid and abrasive streams are continuously variable, are regulated in a stepwise manner (ie high-medium-low), or are controlled in a simple on-off manner. The tool may also be used with a foot pedal or other such control mechanisms The invention may also control the composition of the abrasive material stream and the fluid stream, such as pressure, flow rate, temperature and the like. The tool can also be made adaptable to operatory compressors, and water and electrical supply outlets as allowed by available technology.
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patent: 49849
Ardem Inc.
Bazerman & Drangel P.C.
Lewis Ralph A.
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