Dentistry – Apparatus – Having heater or electrode
Reexamination Certificate
2000-08-18
2002-07-09
Manahan, Todd E. (Department: 3732)
Dentistry
Apparatus
Having heater or electrode
C219S223000, C219S229000
Reexamination Certificate
active
06416320
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a dental instrument, in particular, an instrument for use in root canal therapy and more particularly in the final stages of root canal therapy during obturation of the root canal systems. In the latter instance, the instrument is capable of thermo-softening gutta percha in the root canal as well as searing off gutta percha in the root canal utilizing a controlled-temperature instrument.
BACKGROUND OF THE INVENTION
At the present time, in root canal therapy, filling material such as gutta percha is inserted into the root canal and deformed, usually by the application of heat and pressure. The gutta percha is then able to flow into many irregularities of the prepared root canal, thus allowing for a three-dimensional obturation and sealing to occur. More specifically, when the gutta percha is softened, it is able to be compressed into the numerous aberrations of the root canal in order to effectively seal the root canal cavity.
The compressing of the gutta percha is performed by using a root canal filling spreader and filling condensors. Some prior art root canal spreader and filling condensers are made of stainless steel or nickel-chromium plated brass. The filling spreaders are smooth, flat-ended and slightly tapered. The conventional means for achieving a heated instrument tip is to heat the tip externally, for example, by holding the tip in a flame or in contact with a resistive heater. One disadvantage of this is that the instrument cools off quite rapidly. Thus, to overcome this and achieve the desired degree of heating at the end of the tip, it is often necessary to heat the tip until it glows. However, this increases the risk of accidental burns and tends to rapidly destroy the tip.
In the obturation of root canal systems during root canal therapy, it is usually necessary to sear off gutta percha, i.e., to apply heat to burn off unwanted filling material (excess gutta percha). This is often accomplished by introducing a dental instrument, such as a so-called plastic instrument, into an existing flame, such as that provided by a Bunsen burner, to heat the same and then applying the heated plastic instrument to the pulp chamber of the tooth having excess gutta percha. In this manner, excessive gutta percha is burned off so that only an amount of gutta percha necessary in the root canal is present. It should be recognized that although gutta percha is a commonly used substance to fill root canals, other deformable or heat moldable material are occasionally used to fill the root canals, but gutta percha will be used hereinafter as synonymous with a filling material for the purposes of this application.
There are several problems with this conventional method. First, the burning flame of the Bunsen burner is a hazard that may ignite other flammable material. Second, the flame must be kept constantly burning during the obturation of the root canal in view of the fact that it is used intermittently during the obturation procedure and it is not cost effective to continually extinguish and relight the flame. Third, the flame is often of such magnitude that it frightens patients (who may not be used to undergoing a dental procedure in the vicinity of a burning flame). Fourth, this obturation method requires frequent transfer of the heated dental instrument between the flame and the patient's mouth. During such transfer(s), it is a continuous hazard that the instrument may inadvertently fall, burning something, more significantly and harmfully burning the mouth of the patient. Further, in view of the necessity of such transfer(s) between the flame and the patient's mouth, there is an obvious loss of heat, i.e., the instrument cools somewhat after it is removed from the flame and before it is used operatively in the patient's mouth. This loss of heat may be significant in view of the fact that the filling material, i.e., the gutta percha, will not melt if the instrument has cooled to a temperature below the melting temperature of the gutta percha.
In the prior art, the general endodontic process for filling a root canal in a tooth with gutta percha is described in U.S. Pat. No. 4,480,996 (Crovatto), U.S. Pat. No. 4,525,147 (Pitz et al.), U.S. Pat. No. 4,681,545 (Lapcevic), U.S. Pat. No. 4,894,011 (Johnson) and U.S. Pat. No. 5,067,900 (McSpadden).
U.S. Pat. No. 4,992,045 (Beisel) describes a self-contained heated root canal dental instrument which combines the operations of a root canal spreader, a root canal condenser and a root canal filling material beater. The instrument includes a frame and a heatable probe mounted to the frame and projecting outward therefrom. Heating means are arranged in connection with the frame for heating the probe. A battery is housed in the frame to provide power to the heating means. A switch is electrically coupled to an interposed between the heating means and the battery.
A similar type of instrument is the Endotec II™ thermal condensor for gutta percha sold by Lone Star Technologies. This instrument is a cordless hand-piece with a quick-change top and enables a dentist to thermo-soften gutta percha in the root canal with a specially designed and shaped, electrically heated instrument tip. The amount of heat is purported to be precisely controllable by the dentist by depressing a heat activator button. Use of this instrument purports to provide the advantage of causing gutta percha to coalesce and fuse into a dense, homogeneous mass. Also, the gutta percha adapts to the shape of the root canal under pressure. A problem with this instrument is the fact that the tip is continuously exposed and uncovered and thus, when heated, can cause damage, e.g., burns to the dentist or patient.
Another inconvenience arises from the fact that the manufacturer suggests inserting the instrument tip into the root canal and then heating the probe by depressing the heat activator button. Although this avoids the problem of having a heated tip exposed before the actual procedure, it causes a delay in the treatment because the tip is only heated after it is inserted into the root canal and not before. Thus, the dentist must wait for the tip to be heated while in the root canal and then perform the necessary application of pressure to soften the gutta percha.
OBJECTS AND SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide new and improved methods and apparatus for condensing root canal filling material and searing off gutta percha during the obturation phase of root canal therapy.
It is another object of the present invention to provide new and improved methods and apparatus for condensing root canal filling material and searing off gutta percha during the obturation phase of root canal therapy that are safe and effective.
It is yet another object of the present invention to provide new and improved methods and apparatus for condensing root canal filling material and searing off gutta percha during the obturation phase of root canal therapy which substantially avoid the problems with conventional methods and apparatus mentioned above.
It is still another object of the invention to provide a new and improved dental instrument that includes a metal component that is heatable in a safe manner and can be applied in a safe manner to conduct dental treatment in a patient's mouth which requires the application of heat.
It is still another object of the present invention to provide a new and improved dental instrument that avoids the potentially obtrusive presence of a continually burning flame in proximity to the dental patient during dental procedures.
It is yet another object of the present invention to provide a new and improved instrument for condensing root canal filling material and searing off gutta percha during the obturation phase of root canal therapy which enables the instrument tip to be safely heated prior to insertion into a patient's mouth.
It is still another object of the present invention to provide a new and improved dental instrument which in
Roffe Brian
Roffe Tara
Manahan Todd #E.
Roffe Brian
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