Dentistry – Apparatus – Hand manipulatable implement
Reexamination Certificate
2000-11-06
2002-04-23
Lewis, Ralph A. (Department: 3732)
Dentistry
Apparatus
Hand manipulatable implement
Reexamination Certificate
active
06375463
ABSTRACT:
BACKGROUND
1. Field of the Invention
The invention disclosed herein are in the field of dental instruments. More particularly, the inventions relates to dental wedges which are utilized to separate teeth in preparation for a dental procedure involving the use of dental matrix bands that are positioned around a dental preparation to act as a form for the material used to fill the preparation.
2. Background Art
In the field of dentistry, dental practitioners often treat patients who have developed cavities on the side of a tooth. When these cavities are located adjacent to neighboring teeth they are known as interproximal cavities. In order to treat cavities on the sides of teeth such as interproximal cavities, the dental practitioner removes the infected portion of the tooth, then deposits a filling such as a resinous material or an amalgam into the tooth preparation.
In order to properly deposit the filling without undesired seepage of the filling material beyond the side of the tooth, typically a matrix band is disposed about the tooth, after which the filling material is deposited. A matrix band is typically a metallic or plastic strip having first and second ends which are joined, thereby forming a mold which is disposed about the tooth. When encircled about the tooth, the matrix band acts as a form, similar in function to a concrete form, providing a mold for the desired shape of the repaired tooth.
In order to maintain the matrix band in a desired position with respect to the tooth to be repaired, small dental wedges are often placed in the interproximal spaces between the matrix band and the teeth adjacent the tooth to be repaired. The wedges also space the teeth adjacent to the tooth to be repaired during the filling procedure. Dental wedges may be used to spread adjacent teeth for a variety of other purposes such as enabling a dental matrix band to be initially positioned around a tooth. Due to the elasticity of the periodontal fibers the teeth will resume their original position after the wedges and matrix bands are removed.
FIG. 1
depicts a tooth
10
encircled by a dental matrix band
20
. A dental wedge
30
is shown being positioned between tooth
10
and adjacent tooth
12
. Pliers
18
are used to hold wedge
30
.
FIG. 2
shows a typical matrix band at
20
before being placed around a tooth.
FIG. 3
shows dental wedge
30
in more detail.
The matrix bands can also be formed from different materials to yield different properties. Traditionally, matrix bands have been prepared from stainless steel. Increasing amounts of matrix bands are being sold which are transparent or translucent to enable radiant energy to pass through the band toward composite material in a preparation to polymerize the composite material.
A significant problem with the use of conventional matrix bands and dental wedges is the tendency of the dental wedges to slip out of their positions in the interproximal spaces. When the wedges slip out from between the teeth, the desired configuration of the restored tooth may be distorted Another problem related to the interface between wedges and dental matrix bands is the potential for injurious slippage during insertion of a wedge. These problems are not solved by the prior art.
In addition to the prior art wedge shown in
FIG. 3
,
FIGS. 4-5
depict other examples of prior art wedges respectively at
40
and
50
and are discussed hereinbelow. Typical wedges have a triangular cross section as shown. This triangular cross section includes a thin apex at the distal insertion end which widens into a flat base at the other end, the proximal gripping end. Each wedge in
FIGS. 3-5
is depicted as having a distal insertion end, respectively shown at
32
,
42
and
52
and a proximal gripping end, shown respectively at
34
,
44
and
54
.
As shown in
FIG. 1
, a wedge is typically placed with the widened end located toward the gum line and with the thin apex extending between the teeth and away from the gums in order to fit properly in an interproximal space. When using such dental wedges, the practitioner is careful to orient the wider end toward the gumline while the more thinner, pointed apex is directed upward between the teeth.
In light of this triangular configuration of typical wedges, it is important to orient the wedge properly with respect to the interproximal space before pressing the body of the wedge, shown respectively in
FIGS. 3-5
at
36
,
46
and
56
, into the interproximal space. In addition, the properly oriented wedge must be precisely guided into the space. However, it is often difficult to orient the wedges correctly within the desired interproximal space in the mouth due to their small size and the difficulty involved in controlling the insertion of the wedge without making the patient uncomfortable or possibly damaging the gums and/or teeth of the patient. Accordingly, a practitioner maintains a solid grip on the wedge in order to strategically align and properly guide the wedge. Of course, it is also necessary for the practitioner to maintain a solid grip on the wedge to avoid dropping the wedge.
The tendency of these wedges to slip due to their shape is further increased due to their smoothness and relative rigidity when tightly gripped, particularly when covered with fluids, such as saliva or blood. Such smoothness and rigidity inherently result from the type of materials used to form conventional wedges. Typical dental wedges are comprised of a rigid plastic or wood, such as that from sycamore trees, having a smooth exterior surface which compounds the difficulties associated with firmly gripping the wedges due to their small size. Note that wedge
30
is formed from wood while wedge
40
is formed from a translucent plastic to enable light to pass through during light polymerization of a composite material Another example of a wedge that has translucent portions is disclosed in U.S. Pat. No. 5,743,738 issued to Baffelli et al., which is hereby incorporated by reference.
A practitioner typically uses small-nosed pliers, known as cotton pliers, to grip a particular wedge and to position the wedge within the mouth. To enhance an practitioner's ability to grasp a wedge, some wedges have a head disposed on the proximal end of the body of the wedge. For example, wedges
40
and
50
, are shown respectively with heads
48
and
58
attached to bodies
46
and
56
. Head
48
has four gripping surfaces,
49
a-d,
which makes it easier to grasp than head
58
. However, since head
48
is typically comprised of a rigid material, such as plastic, pliers still readily slip when contacting such wedges.
After the wedge is initially positioned, the dentist forces the wedge into final position. During the forced insertion, the likelihood of injury is greatest as the pliers or tweezers may slip off the wedge into the soft tissues in a patient's mouth. Additionally, when the dentist attempts to regrasp the wedge with cotton pliers there is also risk of slipping off the wedge. The slippery nature of the wedge may cause the wedge to become dislodged within the patients' mouth or ejected from the pliers onto the floor such that is becomes contaminated.
As indicated above, the slippery nature of wedges combined with the conditions in the oral cavity sometimes enable the wedges to become dislodged after being positioned in an interproximal space. The tendency to be displaced after being positioned may also result from being used in very tight interproximal spaces which makes it difficult to insert a sufficiently significant portion of the body of the wedge into the space.
There is, therefore, a need in the art for a dental wedge which is easily positioned with minimal risk of the positioning instrument slipping off of the wedge.
BRIEF SUMMARY AND OBJECTS OF THE INVENTION
It is therefore an object of the invention to provide an improved dental wedge.
It is also an object of the invention to provide means for preventing slipping of a dental tool used to grip the wedge.
It is another object of the invention to provide a dental we
Fischer Dan E.
McLean Bruce
Lewis Ralph A.
Ultradent Products Inc.
Workman & Nydegger & Seeley
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