Dentistry – Method or material for testing – treating – restoring – or... – Endodontic
Reexamination Certificate
1998-04-07
2001-07-17
Lewis, Ralph A. (Department: 3732)
Dentistry
Method or material for testing, treating, restoring, or...
Endodontic
C433S081000
Reexamination Certificate
active
06261099
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to root canal therapy and, more particularly, but not by way of limitation to a method and apparatus for filling a root canal of a tooth.
2. Description of the Related Art
Root canal therapy is a well-known dental procedure. The procedure includes removing a top portion of a diseased tooth, cleaning the tooth's root canals and pulp portion, filling the extirpated root canals with a rubbery compound, such as gutta percha, and cementing a crown to the tooth.
The root canal of the tooth extends from the pulp chamber to a tip, which is known as the apical foramen, of the tooth's root. In addition, the walls of the root canal form fissures and voids. It is desired to fill these fissures and voids as well as the main root canal during the filling process.
One method of filling the extirpated root canal utilizes a solid cone of gutta percha, which is known as the master cone. The master cone is placed within the root canal. Smaller cones, called accessory cones, are positioned around the master cone completing the filling of the root canal.
Another method of filling the root canal utilizes warmed gutta percha. This warmed gutta percha is injected into an extirpated root canal and allowed to cool completing the filling of the canal.
However, these methods suffer several disadvantages, namely overfilling and underfilling the root canal. An overfill occurs by positioning the master cone of gutta percha or injecting warmed gutta percha past the apical foramen into the surrounding bone and tissue. This positioning of the gutta percha may irritate the bone and periodontal ligament surrounding the tooth.
An underfill occurs with a gutta percha cone by failing to get the cone tip to the apical foramen of the tooth. Using warm gutta percha may also result in underfilling the root canal. Warmed gutta percha flows well in large cavities, but not in small cavities, such as the cavity near the root's apical foramen and the fissures and voids extending from the canal. As a result, using warmed gutta percha requires gutting of the tooth to enlarge the root canal for increasing the flowability of the gutta percha. The gutting of the tooth weakens the root potentially leading to future root fractures.
In addition to the problems of overfill and underfill, both procedures extend the procedure time for filling the root canal.
Accordingly, a method for filling root canals that eliminates overfill and underfill and decreases the procedure time will improve over conventional root canal fill methods.
SUMMARY OF THE INVENTION
In accordance with the present invention, a method of filling a root canal includes measuring the prepared diameter size of the root canal, comparing the prepared diameter size of the root canal to the diameter sizes of a plurality of different sized plugs of filling material, and selecting the plug of filling material providing a substantial match. Each plug of the plurality of different sized plugs of filling material is attached to a carrier instrument.
Once a plug of filling material has been selected, the selected plug is delivered into the root canal utilizing the carrier instrument. The plug of filling material is then detached from the carrier instrument when a tip of the plug resides substantially at the apical foramen of the root canal.
After the delivery of plug of filling material into the root canal, a working portion of a fill instrument is coated with a filling material. The fill instrument is inserted into the root canal until the end of the working portion contacts the plug of filling material, and, then, the fill instrument is spun during its removal from the root canal to deliver the filling material into a remaining exposed portion of the root canal.
An instrument for delivering a plug of filling material into a root canal includes a shaft and a head formed integrally with the shaft. The head includes a tip for receiving a plug of filling material. A handle may be attached to the shaft, and a sleeve may surrounding the shaft such that it abuts the plug of filling material to prevent the driving of the tip of the shaft further into the filling material during the delivery of the plug of filling material into the root canal.
An instrument for delivering filling material into a root canal includes a shaft and a working portion formed integrally with the shaft for carrying the filling material. The working portion has a length of from 0.25 mm to 15 mm in order to avoid overflowing the tooth with filling material. The working portion includes a helical member that defines a helical flute and that terminates in a rounded tip.
It is, therefore, an object of the present invention to provide a method for filling root canals that eliminates overfill and underfill and is faster than conventional methods.
Another object of the present invention is to provide a carrier instrument for positioning a plug of filling material such that a tip of the plug resides substantially at the apical foramen of a root.
A still further object of the present invention is to provide a dental fill instrument for augering filling material into the root canal.
Still other objects, features, and advantages of the present invention will become evident to those skilled in the art in light of the following.
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Senia Ennio S.
Senia Steven S.
Wildey William L.
Lewis Ralph A.
Lightspeed Technology, Inc.
Walker LLP Jackson
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