Dentistry – Apparatus – Hand manipulatable implement
Reexamination Certificate
2001-07-02
2002-06-11
Lewis, Ralph A. (Department: 3732)
Dentistry
Apparatus
Hand manipulatable implement
Reexamination Certificate
active
06402514
ABSTRACT:
BACKGROUND OF THE INVENTION
1. The Field of the Invention
The present invention is in the field of dental retention devices. In particular, the present invention relates to dental wedges that are used for separating teeth and for holding matrix bands against teeth during dental procedures. Even more particularly, the present invention relates to dental wedges comprising elastomeric sides.
2. The Prior State of the Art
In the field of dentistry, dental practitioners often treat patients who have developed cavities in teeth. In order to treat cavities the dental practitioner removes the infected portion of the tooth and then deposits a filling material such as a composite, a resinous material, or an amalgam into the tooth preparation.
During the dental filling procedure, a matrix band is typically placed against the side of the tooth to keep the filling material within the tooth preparation from flowing beyond the desired boundary of the restored tooth. A matrix band typically comprises a thin metallic or plastic strip that is flexible and can be bent around the tooth being restored. If the matrix band is not properly held in place then the filling may be expressed beyond the tooth preparation, thereby distorting the configuration of the restored tooth and possibly causing ledges or overhangs, which can be problematic to adjacent tissues and inhibit cleaning.
An improper filling can lead to dental discomfort, misalignment of teeth, capture of food particles, infections, and other dental problems. To avoid these problems, and to fix a distorted dental filling, it may be necessary to grind or drill the filling material down to the proper shape, or even replace the filling entirely. It is desirable to avoid this process because it can increase the time and expense of restoring the tooth and can also create anxiety and discomfort for the patient being treated. Accordingly, it is desirable to keep the matrix band in proper placement during the filling procedure so that the dental filling material molds into a shape that approximates the desired shape of the restored tooth and fits precisely.
In order to hold the matrix band in a desired placement, small dental wedges are often placed in the interproximal spaces between the matrix band and the adjacent tooth. Sometimes, dental wedges are also used to separate the teeth to make room to accommodate, or to compensate for, the thickness of the matrix band between the teeth. Existing dental wedges are typically composed of a wood or semi-rigid plastic material having properties that enable the dental wedge to be slightly deformed while maintaining a sufficiently rigid or semi-rigid structure. These properties generally enable the dental wedge to force teeth apart without damaging the teeth. After the dental wedge is removed the compressed periodontal fibers return to their original dimension and cause the displaced teeth to return to their designated positions.
One inherent problem with the use of dental wedges, however, is that they are prone to slipping out from between the teeth during the dental procedure because the frictional forces holding the dental wedges in place are not adequate. Additionally, existing dental wedges are particularly susceptible to slipping out of place because they are generally incapable of conforming to and accommodating the irregularities of, and between, the teeth. They therefore make only limited contact with the teeth, thereby further limiting the frictional forces necessary to hold the dental wedges in place. This is particularly problematic when the surfaces of the dental wedges become wet and slippery from the patient's saliva or blood, thereby further decreasing the friction that is applied over this limited area of contact between the dental wedges and the surfaces of the teeth.
One attempt to address the problems associates with rigid wedges is the FLEXI-WEDGE, which is made from a semi-rigid plastic material and which has a generally upside-down V-shaped cross section. This makes it capable of flexing along its base as it is forced between teeth. Nevertheless, the FLEXI-WEDGE also suffers from an inability to accommodate and conform to irregularities of, and between, the teeth.
Accordingly, there is currently a need in the art for an improved dental wedge with improved retention capabilities for remaining in place within the interproximal space between teeth, for spacing teeth apart, and for hold matrix bands in proper placement during dental procedures.
SUMMARY OF THE INVENTION
The present invention is directed to improved dental wedges for use in dental procedures. In particular, dental wedges of the invention have retention capabilities that help the dental wedges stay in place when inserted between adjacent teeth.
In one presently preferred embodiment, a dental wedge of the invention comprises a tapered body that is configured to be inserted within the interproximal space between two adjacent teeth. The body comprises a head and a tip and generally tapers from the head to the tip.
The body of the dental wedge also comprises recessed mounting surfaces located on each side of the tapered body. Layers, strips, or other forms of elastomeric material are affixed to each of the recessed mounting surfaces. When the dental wedge is inserted between adjacent teeth, the strips of elastomeric material become compressed as needed between the teeth and the body of the dental wedge. As the strips of elastomeric material are compressed, they bulge out and extend beyond the surfaces of the teeth against which they are compressed. This increases the surface area over which friction is applied and also causes the dental wedge to apply multi-directional forces to the surfaces of the teeth, thereby holding the dental wedge in place and keeping the dental wedge from slipping out from between the teeth. To further increase the frictional forces holding the dental wedge in place, the elastomeric sides may be textured, such as with a gritty surface.
The present invention contemplates the use of elastomeric materials that are completely resilient, i.e., materials that will spring back to their original shape after being deformed. On the other hand, it may be desirable, in some cases, to utilize an elastomeric material that is not entirely resilient but which exhibits some degree of semi-set or deformation memory. This allows the wedge to be deformed during placement to a desired degree without the resiliency of elastomer thereafter substantially increasing the level of spreading force between the teeth while still being able to rebound enough to conform to the irregularities of, and between, the teeth. Conforming to the irregularities of the teeth not only increases the frictional force between the wedge and teeth but also helps to prevent the dental filling material from expressing into gaps associated with the irregularities prior to setting.
In one preferred embodiment, the elastomeric material comprises a thermoplastic elastomer. It should be appreciated, however, that the elastomeric material can comprise any substance having elastomeric properties. Other suitable elastomers include, but are not limited to rubber, silicone, latex, chemical set and thermoset elastomers, and equivalents. The strips of elastomeric material that are deposited on the tapered body can also vary in thickness in order to alter the retention capabilities of the dental wedge. For example, the elastomeric material may be deposited in greater thickness near the tip or center portions of the dental wedge, or they may follow the same contours as conventional wedges that are not elastomeric. They may be convex, concave or irregular so as to accommodate any desired situation.
The elastomeric material can be affixed to the body of the dental wedge by any suitable process, such as by casting or co-molding together with the other structural components of the dental wedge. The elastomeric material can also be manufactured separately from the body and subsequently affixed to the body with any suitable attachment means, such as with ultrasonic wel
Fischer Dan E.
McLean Bruce S.
Lewis Ralph A.
Ultradent Products Inc.
Workman & Nydegger & Seeley
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