Dentistry – Apparatus – Having absorption means or means to isolate tooth or mouth...
Reexamination Certificate
2002-03-28
2003-09-02
O'Connor, Cary E. (Department: 3732)
Dentistry
Apparatus
Having absorption means or means to isolate tooth or mouth...
Reexamination Certificate
active
06612839
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of The Invention
Applicant's invention relates to a gingival retractor for placement at or into the gingival crevice surrounding a tooth and used to deflect gingival tissues away from the tooth to aid in dental procedures. More particularly, the present invention relates to a gingival retractor that can be used in dental procedures without the incorporation of dental retraction cords thus minimizing or eliminating trauma to the surrounding gingival tissue.
2. Background Information
Crowns and bridges are common dental procedures. With these dental procedures, the upper portion of a tooth is prepped down into shape as an abutment and replaced by a prosthetic crown. The tooth is typically prepped to a margin being at or slightly below the gum line and defined by the surrounding gingival tissue. A moldable impression material such as a vinyl-based elastomer or polyvinylsiloxane (PVS) is placed over the tooth and allowed to cure, resulting in an impression of the patient's teeth. This impression is then used by a dental laboratory to produce a prosthetic crown for the patient. The prosthetic crown is then permanently cemented onto the prepared tooth.
The fit of the crown at the margin is critical in order to maintain prolonged life of the prepared tooth in the margin area without decay. In order to ensure that the crown will fit into the margin area to maintain the life of the prepared tooth, it is important that the impression material be able to flow somewhat below the margin of the prepared tooth. Unfortunately, since the margin is at or below the gum line, gingival tissue without insertion of any devices typically blocks the flow of impression material below the gum line.
Currently in order to solve this problem retraction cords have been used to temporarily deflect gingival tissue away from the tooth to expose the margin. In such a situation, prior to tooth preparation a flexible retraction cord is packed into the gingival crevice surrounding the prepared tooth. This cord is placed below the gum line and is used to separate the gingival tissue from the tooth in the margin area. Such packing of the cord almost always induces bleeding and gingival tissue tearing in the patient's mouth. The retraction cord is then removed immediately prior to making the impression. In theory, this permits the impression material to flow into the margin area for reproduction. In practice however, the insertion of the retraction cord into the gingival tissue causes some amount of bleeding that impression is rather difficult. Furthermore, since the retraction cord has to be removed before the impression can be made, the gingival tissue often relapse back to its original formation, particularly with healthy gum tissue, thus defeating the purpose of deflecting the gum tissue.
There exists a need in the dental industry for a gingival retractor that does not cause such excess damage to the surrounding gingival tissue and can be left in place without trauma while the dental impression is made so as to prevent the gum tissue from relapsing back into place. The present invention fulfills this need and provides additional advantages. The gingival retractor of the present invention when used for final impression for dental procedures provides a non-contaminated, safe, clear and clean working area to accurately establish marginal integrity of the prep. In addition, it is easier to place since the present invention can be used in multiple pieces which can be placed at the sides of the tooth one at a time rather than all at once which is the case with the retraction cord. Furthermore, there is less extension of pocket depth with the present retractor especially when compared to the double cord system which could extend pocket depth up to 2 mm beyond the original pocket depth of 1.8-2.0 mm. Also, there is less contamination and bleeding can be easily controlled with the present invention unlike the retraction cord which after removal causes the tissue to bleed and causes contamination of the margins. In addition, there is no tissue relapse because the present invention is left in place until after the impression is taken unlike the retraction cord which when taken out of the gingival crevice tends to relapse and interfere with the margin. Also, the present invention will adapt well in the sulcus, so it is good for tissue management because the present invention will not require a repetitious placement like the cord and the tissue will not dry out as with the cord. Furthermore, the present invention can be modified within obvious parameters to accommodate different sizes and shapes of teeth. In addition, the present invention can be modified to adapt to the gingival crevice or to the tooth which is not possible with the cord.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a novel gingival retractor.
Still another object of the present invention is to provide a novel gingival retractor that incorporates a flexible brace.
It is yet another object of the present invention to provide a novel gingival retractor that incorporates prongs or legs extending from the flexible brace.
Yet another object of the present invention is to provide a novel gingival retractor that incorporates a brace cushion.
In satisfaction of these and related objectives, Applicant's present invention provides a gingival retractor for use in dental procedures. This gingival retractor is for placement at or into the gingival crevice surrounding a tooth and used to deflect gingival tissues away from the tooth to aid in dental procedures. Applicant's invention permits its practitioner to perform dental procedures on patients without the use of retraction cords.
REFERENCES:
patent: 2749616 (1956-06-01), Curry
patent: 4465462 (1984-08-01), Ticknor
patent: 4871311 (1989-10-01), Hagne
patent: 5114341 (1992-05-01), Kassel
Evans Michelle
Gunn, Lee & Hanor P.C.
O'Connor Cary E.
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