MEDICAL APPARATUS FOR ADMINISTERING HEAT TREATMENTS PARTICULARLY USEFEUL IN

DENTAL ROOT CANAL TREATMENTS

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to medical apparatus and methods for administering heat treatments to a preselected body tissue. The invention is particularly useful in administering a dental root canal treatment, and is therefore described below with respect to such application, but it will be appreciated that the invention could also be advantageously used in many other applications.

Many medical treatments involve the application of heat to a preselected body tissue. One example of such a medical treatment involves the application of heat to the root canal of a patient's tooth, as described for example in US Patent 6,482,008. This patent describes a method and apparatus for devitalizing a root canal of a tooth by electrical pulses of high frequency and power values preselected according to the type of tooth being treated. As described in that patent, the electrical pulses disintegrate the vascular nerve matter, coagulate the part of the vascular bundle that is not destroyed, and sterilize or disinfect the root canal. The electrical pulse is applied by a needle-type electrode introduced into the root canal, and the electrical energy applied can be preselected by depressing the appropriate button for the type of tooth, e.g., incisor, canine, premolar or molar.

In such a root canal heat treatment, it is necessary to supply sufficient electrical energy to the electrode to produce the desired heat treatment, but it is critical that no more be applied so as to protect the body tissue from excess heating. Similar problems are involved in other medical heat treatments, for example in ablation treatments to remove selected tissue, in electrocutting treatments, etc.

OBJECTS AND BRIEF SUMMARY OF THE PRESENT INVENTION

A broad object of the present invention is to provide medical apparatus and methods for administering a predetermined heat treatment to a selected body tissue in a manner which protects the body tissue from excessive heating. A more particular object of the present invention is to provide a dental apparatus and method particularly useful for the heat treatment of teeth root canals.

According to one aspect of the present invention, there is provided medical apparatus for administering a predetermined heat treatment to a preselected body tissue, comprising: an electrode for contacting the body tissue to receive the heat treatment; and a pulse generator electrically connected to the electrode for applying thereto an electrical pulse of sufficient energy for administering the heat treatment when the electrode is in contact with the body tissue; characterized in that the apparatus further comprises a heat— sensitive device which automatically interrupts the electrical connection upon the application to the electrode of sufficient energy by the pulse generator to administer the predetermined heat treatment, and to thereby protect the body tissue from excessive heating.

According to further features in the described preferred embodiment, the heat- sensitive device is an electrical fuse constructed integrally with the electrode. More particularly, the electrode is in the form of an electrode unit including an exposed electrically-conductive section at one end for contacting the body tissue, an electrical connector plug at the opposite end for insertion into a socket in the pulse generator, and the electrical fuse between the electrically— conductive section and the connector plug. The electrical fuse, and its electrical connections to the electrically-conductive section and connector plug, are covered by an insulating jacket to permit manually handling the electrode unit. Preferably, the apparatus includes a plurality of such electrode units having fuses of different values selectively insertable into the socket of the pulse generator according to the respective heat treatment to be administered.

According to another aspect of the present invention, there is provided a handpiece connectable to a pulse generator for administering a predetermined medical heat treatment to a preselected body tissue, the handpiece comprising: an electrode electrically connectable to the pulse generator and having a section constructed for engaging the body tissue to which the heat treatment is to be administered; and a heat-sensitive device which automatically interrupts the electrical connection of the electrode to the pulse generator upon the application to the electrode of sufficient energy by the pulse generator to administer the predetermined heat treatment, and to thereby protect the body tissue from excessive heating.

According to yet a further aspect of the present invention, there is provided a method of administering a predetermined heat treatment to a preselected body tissue, comprising: contacting the body tissue with an electrode connected to a pulse

generator; while the electrode is in contact with the body tissue, activating the pulse generator to apply to the electrode an electrical pulse of sufficient energy to administer the predetermined heat treatment; and automatically interrupting, by a heat-sensitive fuse in the electrical connection from the pulse generator to the electrode, the electrical connection to the electrode upon the application thereto of sufficient electrical energy from the pulse generator to administer the predetermined heat treatment, to thereby protect the body tissue from excessive heating.

As will be described more particularly below, the invention provides a number of advantages when used for administering predetermined heat treatments to preselected body tissues, such as the dental root canal treatment briefly described above. Thus, the invention better assures that sufficient energy will be applied to the electrode to administer the predetermined heat treatment in a manner which protects the body tissue from excessive heating. In addition, since each electrode unit used in the heat treatment would be sterilized and precisely formed for the respective root canal, it precludes the possibility of reusing an electrode unit which may have become infected or deformed from a prior use.

Further features and advantages of the invention will be apparent from the description below.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:

Fig. 1 illustrates one form of medical apparatus constructed in accordance with the present invention for administering a predetermined heat treatment to a preselected body tissue, in this case a root canal treatment as described in the above- cited US Patent 6,482,008;

Fig. 2 is a sectional view of the dental handpiece in the apparatus of Fig. 1; Fig. 3 is an enlarged sectional view of the socket end of the dental handpiece of Fig. 2, particularly illustrating the electrode unit receivable within the handpiece for insertion into the tooth root canal; Fig. 4 is a view corresponding to that of Fig. 3, but more particularly illustrating the construction of the electrode unit;

and Fig. 5 illustrates a plurality of electrode units having fuses of different values which may be included in a kit and which are selectively insertable into the socket of the handpiece according to respective heat treatment to be administered.

It is to be understood that the foregoing drawings, and the description below, are provided primarily for purposes of facilitating understanding the conceptual aspects of the invention and possible embodiments thereof, including what is presently considered to be a preferred embodiment. In the interest of clarity and brevity, no attempt is made to provide more details than necessary to enable one skilled in the art, using routine skill and design, to understand and practice the described invention. It is to be further understood that the embodiments described are for purposes of example only, and that the invention is capable of being embodied in other forms and applications than described herein.

DESCRIPTION OF A PREFERRED EMBODIMENT

As indicated earlier, the present invention relates to apparatus and methods for administering predetermined heat treatments to a preselected body tissue in a manner to protect the body tissue from excessive heating. For purposes of example, the invention is described below with respect to the dental apparatus and method for administering heat treatments to root canals in teeth, as described in the above-cited US Patent 6,482,008, the contents of which are expressly incorporated herein by reference.

The apparatus illustrated in Fig. 1 includes a pulse generated, generally designated 10, constituted of a housing 20 which includes the electrical power supply and electronic circuitry for generating high frequency electrical pulses, and a handpiece 30 carrying an electrode unit 40 for applying the high frequency electrical pulses to the interior of the tooth root canal being treated. Thus, as shown in Fig. 1, housing 20 includes an electrical output line 21 connected to handpiece 30 for applying the high frequency electrical pulses to the electrode unit 40. In addition, housing unit 20 includes another line 22 connected to a lip clip 23 to be clipped to the lip of the subject receiving the treatment, and a further line 24 connected to a bare handlebar 25 to be gripped by the person receiving the treatment, all as described more particularly in the above-cited US Patent 6,482,008.

As described in that patent, electrode unit 40 is inserted into the root canal of a tooth being treated for contacting body tissue within the root canal to receive the high

frequency electrical pulse from the pulse generator. The present invention relates particularly to the dental handpiece 30, and more particularly to the construction of the electrode unit 40.

The construction of electrode unit 40 and the respective part of handpiece 30 for receiving it is more particularly illustrated in Figs. 2-4.

Thus, as shown in Fig. 2, handpiece 30 is made of insulating material and of a configuration for convenient grasping by the dentist. It includes a push-button 31 depressible by the dentist when the high frequency pulse is to be applied to the patient after the electrode unit 40 has been inserted into the root canal of the tooth being treated. Push-button 31 is connected by electrical conductor 32 to the output line 21 of pulse generator unit 20, and by electrical conductor 33 to an electrical contact 34 (Figs. 3 and 4) within socket 35 to receive the electrode unit 40.

As shown more particularly in Figs. 3 and 4, electrode unit 40 includes an electrical connector plug 41 at one end for insertion into socket 35 of handpiece 30 to make electrical contact with contact 34 of the handpiece, and an exposed electrically- conductive electrode 42 at the opposite end for insertion into the tooth root canal. Electrode unit 40 further includes an electrical fuse 43 connecting electrode 42 to connector plug 41. It further includes an insulating jacket 44 covering fuse 43, together with electrical connections to electrode 42 and connector plug 41, to facilitate manual handling of the electrode unit. The angle between electrode 42 and connector plug 41 is an obtuse angle, preferably about 110°, to facilitate manipulation of electrode 42 by the dentist.

Fuse 43 is designed to have a value to automatically interrupt the electrical connection from connector plug 41 to the electrode 42 when sufficient energy has been supplied by the pulse generator to the electrode to produce the desired heat treatment, and thereby to protect the body tissue from excessive heating.

As described in the above-cited US Patent 5,482,008, housing unit 20 of the pulse generator 10 includes manually-selectable controls which enable the operator to select different values of electrical energy to be supplied to the electrode, according to the nature of the heat treatment to be applied, and particularly according to the type of tooth to be treated. The dentist would therefore be supplied with a plurality of electrode units 40, e.g., in a kit form as shown in Fig. 5, each having fuses of different values and selectively insertable into the socket 35 of handpiece 30, according to the respective heat treatment to be administered, thereby not only better protecting the

patient from excessive heating, but also better assuring that a previously— used electrode unit, which may have become infected or deformed in one use, will not be re-used.

Thus, in using the apparatus illustrated in the drawings, the dentist would first determine the heat treatment to be applied, and would then select the appropriate electrode unit 40 and insert it into socket 35 of the handpiece 30, according to the selected heat treatment. Since the value of the fuse 43 in the selected electrode unit would correspond to the heat treatment to be applied, the fuse would automatically interrupt the application of electrical energy to electrode 42 as soon as the predetermined amount of electrical energy has been supplied to the electrode, thereby protecting the patient from excessive heating, as well as from a re— use of an electrode unit which may have become infected or deformed by a prior use. Preferably, each electrode unit 40 would be marked according to the value of its respective fuse 43 appropriate for the respective heat treatment to be applied. While the invention has been described with respect to one preferred embodiment, it will be appreciated that this is set forth merely for purposes of example, and that the invention may advantageously be used with other interrupting devices, and in many other applications requiring the administration of a predetermined heat treatment to a predetermined body tissue in a manner which provides protection against over-heating, or re-use of an electrode unit infected or deformed by a prior use.