Dentistry – Apparatus – Having absorption means or means to isolate tooth or mouth...
Reexamination Certificate
1999-11-05
2001-10-09
Lewis, Ralph A. (Department: 3732)
Dentistry
Apparatus
Having absorption means or means to isolate tooth or mouth...
Reexamination Certificate
active
06299446
ABSTRACT:
TECHNICAL FIELD
The invention comprises a frame-like holder for a rubber barrier sheet designated as a cofferdam or rubber dam.
BACKGROUND
During dental treatment, it is frequently desirable or necessary to isolate and shield the tooth or teeth being treated from the neighboring teeth or the oral cavity in general, for instance in order to prevent saliva from contacting the treated tooth or, inversely, to prevent therapeutic fluids and other agents from contacting the area around the treated tooth. This isolating function is realized by means of a rubber barrier sheet designated as a rubber dam and featuring openings that facilitate extending it over the tooth to be treated or other teeth as well. The sheet isolates and shields the teeth tightly, so as to prevent the passage of liquids.
The rubber sheet surrounding the tooth or teeth in this way is fastened to a retaining device that holds it stretched over the oral opening, allowing access only to the tooth or teeth being treated or other teeth as well, so as to realize its function as described.
The devices now familiar for this purpose are either closed full frames or open (U-shaped) frames made of metal or plastic, over which the rubber sheet is laid, which frames feature pointed projections on which the rubber sheet is suspended and thus retained.
This method of retention of the rubber dam, i.e. of anchoring it to the holder, represents a significant problem in rubber dam applications as per the current state of the art. If the rubber dam comes loose from the holder during dental treatment, its protective shielding effect may be lost in the sense that substances on the outer surface of the rubber dam may enter the oral cavity or that substances from the oral cavity may contaminate the tooth or teeth being treated. This occurs in particular during treatment of the rear molars. In this case, fastening down the rubber dam around the teeth to be isolated, for instance using metal clamps, may be a stubborn problem due to tooth forms that are hardly retentive. In such cases, the rubber dam must not be stretched across the holder so as to form a smooth, taut surface (cf. Winkler “Kofferdam in Theorie und Praxis”, Quintessenz Verlags-GmbH 1991), but must rather hang loosely in the frame to some extent. Fulfilling this requirement, however, means the tension required for secure anchoring of the rubber dam to the pointed projections on the frame is lost, greatly increasing the risk of accidental slippage of the rubber dam from the holder.
The purpose of the invention is therefore to provide a frame-like rubber dam holder that is free of the above-described drawback of the current state of the art, thus in particular ensuring secure retention of the rubber dam in all dental treatment situations.
SUMMARY
The invention fulfils this purpose with a holder comprising two practically congruent frame elements, between which the rubber dam can be anchored by means of friction and/or form fit. In this way, the rubber dam is anchored securely to the holder by the elements and action of the holder itself and without requiring tension in the rubber dam, even when a treatment dictates that the rubber dam hang loosely between the legs of the frame.
It is preferable to attach the rubber dam to the holder by having the two frame elements feature interlocking ribs and grooves—the walls of which are placed at appropriate intervals—that deflect the rubber dam and clamp it between the two frame elements. This method of anchoring the dam is independent of any tension in the rubber dam.
It is preferable to design the two frame elements to make a (U-shaped) semi-frame joined by hinged joints at the free ends of the legs of the components. This renders the device easier to work with and facilitates leaving the upper edge of the rubber dam frameless (as is the case in conventional single-element semi-frame holders).
If the ribs and grooves serving to anchor the rubber dam do not exclude the possibility of a lateral shifting of the two frame elements in relation to one another, such a shift during use can be avoided by the additional feature that one of the two frame elements of the holder extend beyond the other when the two frame components are closed.
The known Sauveur frame holder, named after its inventor, is a rubber dam holder comprising two semi-frame elements joined at the free ends of the legs by hinge joints. When hinged open—and not as per the invention when closed—these elements form the rubber dam holder in the form of a closed full frame and the rubber dam is stretched over the surface enclosed by the two semi-frame elements. The hinge axis Is upright In use—and not as per the Invention horizontal—the purpose being to swing away one-half of the rubber darn during treatment to facilitate andodontic x-ray checks. The Sauveur frame retains the rubber dam in as per the currant state of the art by means of the projections on the two semi-frame elements, which projections dig into the rubber dam if the latter is under sufficient tension.
REFERENCES:
patent: 3406452 (1968-10-01), McConville
patent: 3781994 (1974-01-01), Hesselgren
patent: 4204329 (1980-05-01), Kahn
patent: 4544357 (1985-10-01), Williams
patent: 4583946 (1986-04-01), Shanel
patent: 4600387 (1986-07-01), Ross
patent: 4721465 (1988-01-01), Barasz
patent: 4820155 (1989-04-01), Sauveur
patent: 5931673 (1999-08-01), Bolbolan
patent: 273 811 (1951-05-01), None
patent: 196 32 084 C1 (1998-02-01), None
patent: 0137090 (1983-10-01), None
patent: 0 178 238 A1 (1986-04-01), None
patent: WO 96/29952 (1996-10-01), None
Lewis Ralph A.
Merchant & Gould P.C.
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