Dentistry – Prosthodontics – Holding or positioning denture in mouth
Reexamination Certificate
1999-03-05
2001-01-09
Lewis, Ralph A. (Department: 3732)
Dentistry
Prosthodontics
Holding or positioning denture in mouth
C433S180000, C156S272400
Reexamination Certificate
active
06171107
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to methods, compounds and devices for adhering items together and more specifically, to adhesive and removal methods and apparatus for securing and removing secured items such that they are removed through the application of magnetic fields.
Throughout daily life, there are many occasions requiring that two or more items be secured to one another. For example, in the field of dentistry, there are several ways to permanently secure prosthodontics such that they maintain a proper spatial relationship to either part of an existing tooth or a dental implant. A more commonly employed technique involves the use of some form of dental cement placed between the tooth or implant and the prosthodontic device. Dental cement chemistry is a complex science and the actual method of “affixation” varies. In some types of dental cement, the cement flows into surfaces characterized by micro roughness on the items being cemented. These micro rough surfaces hold onto the cement once the cement has set, thus holding the items together.
While these cements allow for a firm bond, removing the cemented prosthodontics can be difficult, time consuming, and uncomfortable for both the patient and the dentist. Additionally, physical forces generated in conventional removal processes can damage the underlying tooth or implant. For this reason many affixed prosthodontic devices are infrequently removed for examination, except when dental problems arise.
In the field of prosthodontics, it has been known to employ magnets for securing items together. However, this use of magnetism has hereto been restricted to applications involving affixation between two prosthodontic devices such as an implant and a crown, bridge, or denture. One problem with prior magnetic affixation, typically using a magnet and a ferromagnetic material to which the magnet holds (or another magnet), is the lack of holding power to prevent relative movement between the affixed components. U.S. Pat. No. 4,693,686 (Sendax) incorporates pairs of magnets with one magnet positioned within an implant and the other magnet positioned within a prosthodontic device. The attractive forces between these magnets secure the prosthodontics. U.S. Pat. No. 4,214,366 (Laban), U.S. Pat. No. 5,788,493 (Tanaka et al), U.S. Pat. No. 5,678,998 (Honkura et al), U.S. Pat. No. 5,611,689 (Stemmann), and U.S. Pat. No. 4,997,372 (Shiner et al) all use variations in design of similar concepts. Other patents such as U.S. Pat. No. 5,636,990 (Stemmann), U.S. Pat. No. 5,254,006 (Yamada), and U.S. Pat. No. 5,013,243 (Tanaka et al) function in similar ways, but use the attractive forces between a single magnet and a ferromagnetic material to secure prosthodontic devices in position.
SUMMARY OF THE INVENTION
The present invention relates to a method, compound and apparatus for securing two items together and magnetically assisted separation of the secured items. An adhesive with magnetic particles therein is employed to secure two items together, and, should it be desired to separate the secured items, applied magnetic fields are used to assist in the removal or separation of the secured items. In this manner, the affixation strength of conventional methods is maintained yet removal is considerably simplified, with less potential for damage to the underlying structures of the secured items.
In a particular embodiment, the method, adhesive compound and apparatus are employed in the field of affixing prosthodontic devices by applying a layer of dental cement between the two surfaces of the mating devices. Accordingly, an embodiment of the invention comprises a cement that contains magnetic particles, suitably homogeneously interspersed within the cement. A feature of this embodiment is the ability of the cement to be broken up by the “shaking” of the magnetic particles in response to the application of an alternating electromagnetic field.
In another aspect of the invention, outwardly biased arms in a first portion engage corresponding catches in a second portion. The arms include magnetic portions thereon, whereby application of magnetic fields of proper polarity will urge the arms inwardly against the bias, and out of the catch portions, to enable separation of the first and second portions. However, in absense of the proper magnetic fields, the items are held together.
Accordingly, it is an object of the present invention to provide an improved adhesive for adhering items together.
It is a further object of the present invention to provide an improved an improved adhesive enabling easier separation of secured items when desired.
It is another object of the present invention to provide an improved adhesive for securing prosthodontic devices that enables easier removal.
Another object of the invention is to provide and improved apparatus for affixing prosthodontic devices together.
It is a further object of the present invention to rovide an improved apparatus and method for removing prosthodontic devices.
It is yet another object of the present invention to provide an improved magnetic apparatus and method that enables quick and simple separating of prosthodontic devices.
The subject matter of the present invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. However, both the organization and method of operation, together with further advantages and objects thereof, may best be understood by reference to the following description taken in connection with accompanying drawings wherein like reference characters refer to like elements.
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Dellett and Walters
Lewis Ralph A.
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