This invention relates to a matrix band retention device for separating adjacent teeth and holding a matrix band in proper placement during a dental restoration procedure, a system that includes the device, and a method of preparing a tooth for restoration using the system.
When a patient develops caries in a tooth, the dental practitioner removes the infected portion of the tooth, prepares the tooth for restoration, and then restores the tooth by depositing a filling material into the tooth cavity preparation. To prepare the tooth for the filling, a matrix band is typically placed against the side of the tooth to approximately define the desired shape for the restored tooth, and as a means to prevent overflow of the filling material beyond the tooth boundary. The matrix band typically comprises a flexible metallic or plastic strip that can be bent around the tooth being restored. If the matrix band is not properly adapted to the tooth contour, and if it is not retained properly in place throughout the restoration procedure, then too much or too little filling material may be deposited in the tooth cavity preparation, and the filling material may flow out of the tooth cavity preparation, thereby distorting the configuration of the restored tooth and creating costly finishing and polishing procedures to correct the distorted restoration.
To place the matrix band into the desired position, particularly for proximal restorations, it is often necessary to separate the teeth by placing small dental wedges in the interproximal space between the teeth, and while the wedges press the matrix band to the proximal surface of the tooth, they are not effective in pressing the matrix band to the other tooth surfaces where the matrix band bends around the tooth, i.e., to the facial and lingual surfaces close to the line angle. In addition, the wedges are subject to slipping from their position, which causes movement of the matrix band. Matrix band retainers have also been used, with or without additional dental wedges. These conventional matrix band retainers have a generally ring-shaped body with a pair of tines extending perpendicularly downward from the ends of the ring-shaped body such that the tines are adjacent the interproximal space for adapting the ends of the matrix band to the tooth surfaces and retaining the matrix band in that position during the restoration procedure. However, many of these retainers do not provide a firm and complete adaptation of the matrix band and many are subject to slipping out of position. Also, tensioning instruments, such as forceps, are generally used to engage the ends of the ring-shaped body to place the tines in the desired position. While numerous matrix band retainers have been developed, many require a special pair of forceps designed specifically for that matrix band retainer, and many are difficult to manipulate. There is currently no matrix band retaining device or system that is easy to manipulate, that is effective to both separate adjacent teeth and adapt and retain the matrix band in an efficient and reliable manner, and that may be operated using any of the many forceps available on the market.
The present invention provides a device that achieves interproximal separation as well as matrix retention and adaptation during a dental restoration. To this end, a body member having a pair of spaced apart ends is provided with a pair of tines that extend downwardly from the ends to be positioned adjacent the interproximal space between the tooth to be restored and an adjacent tooth. A wedge element is integral with each tine and extends inwardly toward the wedge element of the other tine, such that upon placement of the body member in the oral cavity, the wedge elements are capable of being wedged between the adjacent teeth in the interproximal space, thereby achieving separation. Additionally, the wedge elements adapt the matrix band to the proximal surface of the tooth to be restored. A cushion element is positioned about and engageable with each of the tines between the wedge element and the end of the body member. When the body member is placed in the oral cavity, with the wedge elements wedged into the interproximal space, the cushion elements adapt the ends of the matrix band to the tooth contour, i.e., from the proximal tooth surface to the facial and lingual tooth surfaces and retain the band in place softly, yet firmly, such that the matrix band is held in a stable position throughout the restoration procedure. In an exemplary embodiment, the device includes U-shaped grooves formed in the top surface of the ends of the body member and extending downwardly into the tines in general alignment with the wedge elements. The grooves are compatible with numerous available tensioning instruments, and upon manipulation of the body member, torque is avoided during placement of the device in the oral cavity, thereby making the device easy to use and manipulate.
The present invention further provides a system for separation and matrix band retention for use during a dental restoration, the system including at least one matrix band, a matrix retention device having the body member with tines and inwardly extending wedge elements, and at least one pair of cushion elements for positioning on the tines of the retention device. The present invention further provides a method for preparing a tooth for a restoration, the method including providing a device having the body member with tines and inwardly extending wedges, and having the cushion elements placed on the tines, then placing a matrix band in the interproximal space between the tooth to be restored and an adjacent tooth. The tines of a tensioning instrument are then inserted into the grooves of the retention device and the tensioning instrument is manipulated to push the spaced apart ends further apart. When the body member is positioned in an appropriate place in the oral cavity, the tensioning instrument is released to bring the spaced apart ends back toward each other to insert the wedge elements into the interproximal space between the matrix band and the adjacent tooth to press the matrix band to the proximal surface of the tooth to be restored, and also to press the cushion elements against the ends of the matrix band to adapt them around the tooth toward and against the facial and lingual surfaces. In another exemplary embodiment, the cushion elements comprise a microporous plastic that is capable of absorbing fluids around the tooth to be restored, and the cushion elements are removable and replaceable.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the invention.
The present invention provides a separation and matrix band retention device that is simultaneously effective to both separate a tooth to be restored from its adjacent tooth and to adapt and retain a matrix band against the tooth contour throughout the restoration procedure in a manner that is comfortable to the patient and yet firm so as to prevent slipping of the device and the matrix band during the procedure. The device of the present invention is easy to manipulate and may be used with many of the currently available tensioning instruments on the market. The present invention further provides a system that includes the device, as well as a method of preparing a tooth to be restored utilizing the system. The present invention may be best understood with reference to the drawings, in which like numerals are used to refer to like parts throughout.
Extending downwardly from the spaced apart ends 44, 46 are a pair of tines 60, 62. The tines 60, 62 may extend perpendicularly from the body member 42 or may be angled, as desired. The tines 60, 62 are integral with the body member 42, including a single-piece construction or mechanical attachment, such as screws or an adhesive bond. The tines 60, 62 may be the same or a different material than the body member 42. For example, body member 42 may be made of a flexible metal or long fiber-reinforced flexible plastic, while the spaced apart ends 44, 46 and tines 60, 62 are made of a different and/or rigid plastic material. In one embodiment, the spaced apart ends 44, 46 and tines 60, 62 are of single-piece construction and made from a rigid plastic material, and are mechanically or adhesively attached to body member 42, which comprises a flexible material. Extending inwardly from the tines 60, 62 are a pair of wedge elements 64, 66. The wedge elements 64, 66 are integral with the tines 60, 62, and as a result, the use of separate wedges is eliminated. The separate wedges of the prior art were subject to slipping out of place, whereas the integral wedge elements 64, 66 of the present invention are not subject to slippage. Again, the term “integral” contemplates single-piece construction or mechanical attachment, though single-piece construction is preferred due to the stress placed upon the elements that could cause failure in a mechanical bond, such as an adhesive bond. Thus, in one embodiment, the spaced apart ends 44, 46, the tines 60, 62, and the wedge elements 64, 66 are of single-piece construction and made from a rigid plastic material, and are mechanically or adhesively attached to body member 42, which comprises a flexible material.
In one embodiment, shown most clearly in side view in
In another embodiment, depicted in side view in
In yet another embodiment, depicted in side view in
Device 40 further includes a pair of cushion elements 70, 72 positioned about and engageable with tines 60, 62, respectively. Cushion element 70 is positioned on tine 60 between the spaced apart end 44 and the wedge element 64. Similarly, cushion element 72 is positioned on tine 62 between spaced apart end 46 and wedge element 66. Cushion elements 70 and 72 each have an outer surface 70a, 72a, respectively, and in inner surface 70b, 72b, respectively. Inner surfaces 70b, 72b engage the outer surfaces 61, 63 of tines 60, 62, respectively. The outer surfaces 70a, 72a of cushion elements 70, 72 will engage the ends 32, 34, respectively, of matrix band 30 upon placement of the device 40 in the oral cavity 10. Advantageously, the outer surfaces 70a, 72a of the cushion elements 70, 72 are such that a portion of each cushion element extends over its respective wedge element 64, 66 one-third to two-thirds the length of the wedge element 64, 66, wherein the length is defined as the distance from the outer surface 61, 63, respectively, of the tines 60, 62 to the respective tip 65, 67. As shown in
In an exemplary embodiment of the present invention, the cushion elements 70, 72 comprise a microporous plastic that has the mechanical stiffness necessary for adapting the ends 32, 34 of the matrix band 30 as well as elasticity to provide a soft cushion that is gentle to soft tissue, yet firm enough to hold the matrix band against the tooth contour. The microporous plastic may be high density polyethylene, polytetrafluoroethylene, ultra-high molecular weight polyethylene, nylon-6, polypropylene, polyvinylidene fluoride, polyethersulfone, and combinations thereof. The Porex Porous Products Group, Fairburn, Ga., offers a line of commercially available porous plastics suitable for the cushion elements 70, 72 in the device 40 of the present invention. The microporous plastic may also be a foamed polyurethane elastomer, such as that provided by GTK Timex Group SA, Rivera, Switzerland. The cushion elements 70, 72 may also comprise a silicone or thermoplastic elastomer having a Shore A hardness in the range of about 20-60. Advantageously, the cushion elements 70, 72, for example, the microporous plastic, are capable of fluid absorption in the oral cavity, such that the cushion elements 70, 72 will absorb saliva and/or blood during the restoration procedure. The foamed polyurethane elastomer from GTK Timex Group SA, for example, has a 300-400% water absorption capability with a 25% volume expansion. The cushion elements 70, 72 may also be removable and replaceable, such that device 40 may be used for multiple patients with the cushion elements 70, 72 being replaced for each patient.
The vast majority of the force acting on the tines 60, 62 is distributed to the wedge elements 64, 66, with a much smaller force being distributed to the cushion elements 70, 72. Thus, advantageously, the wedge elements 64, 66 have a significantly higher stiffness than the cushion elements 70, 72. For example, the resiliency ratio of the wedge elements to the cushion elements may be on the order of 1:100 to 1:1000.
In an exemplary embodiment of the present invention, device 40 includes a pair of open grooves 76, 78 formed in spaced apart ends 44, 46, respectively. Advantageously, the open grooves 76, 78 may be V-shaped or U-shaped. The V- or U-shaped open grooves 76, 78 are formed from the top surfaces 45, 47 of the spaced apart ends 44, 46 extending downwardly into the tines 60, 62. The V- or U-shaped grooves are positioned to open inwardly at the outer surfaces 61, 63 of tines 60, 62 in opposition to one another, and are advantageously in alignment with wedge elements 64, 66. When the open grooves 76, 78 are in alignment with the wedge elements 64, 66, torque between the cushion elements 70, 72 and the wedge elements 64, 66 is reduced during manipulation of the body member 42 by a tensioning instrument 50, thereby providing more stability to the device during its insertion into the oral cavity 10. The open grooves are adapted to receive a pair of tines 52, 54 of a tensioning instrument 50 to permit manipulation of the body member 42. By virtue of being an inwardly open V- or U-shape, the grooves 76, 78 are compatible with numerous different tensioning instruments 50 currently available on the market, thereby eliminating the need for a specially designed tensioning instrument.
While the figures depict a flexible, generally ring-shaped body member 42, it may be understood that the device 40 of the present invention is not so limited. A non-flexible body member could be utilized that is manipulated by other means to move the spaced apart end 44, 46 toward or away from each other. For example, a screw-adjusted clamp-type body member could be used. Therefore, while a flexible, generally ring-shaped body member is exemplary and is indicative of the current trend in matrix retention devices, the present invention should not be limited regarding the shape or flexibility of the body member.
Thus, the present invention includes a device 40 having an integral wedge element and a cushioning element for simultaneously separating a tooth to be restored and its adjacent tooth, and adapting and retaining a matrix band to the contour of the tooth to be restored. The present invention further provides a system for separation and matrix retention and adaptation that includes at least one flexible matrix band and the device of the present invention, with at least one pair of cushion elements. The system may further include additional pairs of cushion elements, such that the cushion elements are removable and replaceable after each patient. The system may also further include a tensioning instrument for manipulating the device. Finally, the present invention also includes a method of preparing a tooth to be restored, the method including providing the device of the present invention, inserting a matrix band into an interproximal space adjacent a tooth to be restored, manipulating the device of the present invention with a tensioning instrument to place the device in the oral cavity and then releasing the tensioning instrument to position the device in a manner that separates the tooth to be restored from its adjacent tooth and adapts and retains the matrix band to the tooth to be restored.
While the present invention has been illustrated by the description of one or more embodiments thereof, and while the embodiments have been described in considerable detail, they are not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative device, system and method and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope of the general inventive concept.
This application is a continuation-in-part of co-pending U.S. patent application Ser. No. 10/725,295 filed Dec. 1, 2003 and entitled DEVICE AND SYSTEM FOR SEPARATION AND MATRIX RETENTION AND ADAPTATION DURING DENTAL RESTORATION AND METHOD FOR PREPARING TOOTH USING SYSTEM, which is incorporated herein by reference in its entirety as if completely set forth herein below.
Number | Date | Country | |
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Parent | 10725295 | Dec 2003 | US |
Child | 10904812 | Nov 2004 | US |