United States Patent 3747216

An endodontic instrument combining boring, spraying and cleansing means for concurrent operations in root channels by a programmed treatment, said instrument including novel electro-mechanical means for imparting to the boring tool a composite reciprocating rotational motion on an arc of a chord of about 90° and a uniform continuous rotary motion, the continuous rotary motion being converted to rectilinear translational motion. A suction chamber is part of the instrument and sucks off the solutions used in treatment.

Bassi, Ezio (Imola, IT)
Riitano, Francesco (Soverato, IT)
Application Number:
Publication Date:
Filing Date:
Primary Class:
Other Classes:
433/91, 433/118
International Classes:
A61C1/07; A61C1/18; A61C17/02; (IPC1-7): A61C5/02
Field of Search:
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US Patent References:
3578745DENTAL INSTRUMENT1971-05-18Garnier
3556669N/A1971-01-19Valeska et al.

Primary Examiner:
Peshock, Robert
What is claimed is

1. An endodontic instrument for concurrent operations in boring, spraying and cleansing of dental root channels, comprising in combination:

2. An endodontic instrument as claimed in claim 1, wherein said converting means for converting said uniform continuous rotary motion to a uniform rectilinear translational motion leaves the rotational reciprocating motion unaltered and includes kinematic connecting means for transmitting said composite motion from the electromechanical means to said converting means.

3. An endodontic instrument as claimed in claim 2, including a revolution counter for counting the number of revolutions per minute of the uniform rotary motion which is proportional to the uniform rectilinear movement of said boring tool.

4. An endodontic instrument as claimed in claim 2, including a suction chamber connected to the remaining instrument body by resilient connecting means.

5. An endodontic instrument as claimed in claim 2, wherein said electromechanical means comprises;

This invention relates to an endodontic instrument for carrying out the programmed endodontic treatment steps of boring, spraying and cleansing of dental channels.

As is well known, the endodontic treatment contemplates the following steps:

A. appropriate dressing of the access cavity to the root-pulp channel with removal of pulp in the cavity;

B. location of the opening of the radicular channels and measuring the depth thereof by means of a radio-opaque probe with the aid of X-ray photography;

C. removal of radicular contents and organic waste by means of suitable instruments such as nerve pullers, files and channel-spreaders with spreading of the channels (boring with endodentine removal) to the apex, with cleansing by spraying with suitable chemical solutions, such as sodium hypochlorite and Perihydrol, e.g., a solution of hydrogen peroxide (oxygenated water) at 30 percent, to remove the waste material;

D. final washing step carried out with antibiotic and enzymatic antiseptic solutions;

E. channel drying and tridimensional filling thereof, preferably to the apex and including the secondary canaliculi.

The instrument according to the present invention is designed and constructed to particularly meet the requirements of steps b, c, and d above, commonly referred to as the chemical-mechanical channel dressing.

A critical factor or principle governing these steps lies in the depth-adjustment of the boring, spraying and continuous suction cleansing operations in the presence of lubricants. The reamer or boring means operates better when lubricated and spraying is more effective if hydraulic thrust readily removes the whipped content of the cleansing means. Further suction must readily remove the debris outwardly of the cavity and the channel.

All of the means heretofore developed including the commercial devices for separately carrying out the above operations of boring (see, for examples U.S. Pat. Brenman et al. No. 3,073,031 and Gythfeldt No. 1,682,784), spraying and sucking for cleansing are either partly or totally unsuitable because of the long treatment time required. Reamers and boring means are known but these do not spray and do not suck away debris. The known spraying-sucking means which do not bore are cumbersome. They partially wash the channel, but they do not whip the endocanalar material and their sucking action is not adequate to aboid damage to the endoral mucous membranes because of insufficient collection of the cleansing solutions.

It is the main object of the present invention to concurrently carry out the programmed endodontic procedure for chemical and mechanical channel dressing and at the same time provide for the programmed boring, spraying and cleansing by suction.

A further object is to reduce the working time and at the same time to increase boring effectiveness by lubrication.

These and other objects are attained by the instrument of the present invention which provides simultaneous operations of programmed boring, spraying and cleansing for dental radicular channels, this instrument essentially comprising means for giving a boring tool a composite motion of a rotational reciprocating movement through an arc on a chord of about 90° with a uniform rectilinear translational movement, two or more conduits for delivering different solutions to the proximity of the boring tool for radicular channel spraying, and at least one suction or vacuum chamber for sucking off the solutions and waste and thereby preventing the waste from possibly contacting the oral mucous membranes.

The instrument of the invention is further characterized in that the means for imparting to the boring tool a composite rotational reciprocating motion with a translational motion essentially comprise: an electromechanical device capable of providing a rotational reciprocating motion through an arc on a chord of about 90° with a uniform continuous rotary motion; means for converting the uniform continuous rotary motion to a uniform rectilinear translational motion without altering the rotational reciprocating motion; and kinematic connection means for transferring the composite motion from the electromechanical device to the motion converting means.

The features of the instrument according to the present invention will now be more fully described and shown with reference to a practical embodiment thereof, given as a non-limiting example, and with the aid of the accompanying drawings, in which:

FIG. 1 is an enlarged, partly sectional, longitudinal view showing the instrument as a whole;

FIG. 2 is a longitudinal sectional view on a substantially enlarged scale relative to FIG. 1, showing the tool holder head in operating position;

FIG. 3 is a partly sectional, front view of the tool holder head shown in FIG. 2;

FIG. 4 is a partly sectional, longitudinal view of an electromechanical device for producing a particular motion which is transmitted to the instrument shown in the above figures; and

FIG. 5 is a front view rotated by 90° for the device as shown in FIG. 4.

Referring to the drawings, and particularly FIGS. 1 and 2, reference numeral 1 indicates a handle for accomodating therein a flexible steel cable 2 covered by a sheath 3. The flexible cable 2 is firmly connected to first shaft 4 which is carried through two sleeves 5 by a tube-like element 6 which is threaded to an angle connecting element 7 to connect the handle 1 with a tubular arm 8. Within the tubular arm 8, a second shaft 9 is accomodated and is carried through two sleeves 10 by a coaxial tube-like element 11 which is also threaded to the angle element 7.

This second shaft 9 is connected by kinematic means to the first shaft 4 through a pair of gear wheels 12. A preferred tool holder head 13 is fastened to arm 8 and has its longitudinal axis at right angles to the axis of arm 8.

Referring to FIG. 2, the tool holder head essentially comprises an outer shell 14, partly of a substantially cylindrical shape and partly of a substantially frusto-conical shape. On the frusto-conical portion there is a suitably shaped projection 15 which provides a suction or vacuum chamber and which tapers to an opening 26, described below.

Within the cylindrical portion there is inserted a bushing 17, on the outer surface of which a gear wheel 21 is keyed. Gear wheel 21 meshes with a gear wheel 22 which is keyed on the second shaft 9 of the tubular arm 8. Inside the bushing 17, there is a hole 23 which is segment-shaped in cross-section as shown in FIG. 3, into which the stem 18 for a boring tool 19 is slipped. The tool stem 18 is of a threaded segment cross-section. The threaded stem 18 is screwed into a closing plug 20 for the head and the closing plug 20 is screwed into said outer shell 14. Bushing 16 holds a boring tool 19 in the frusto-conical portion of the outer shell 14.

Three tubes 24 are firmly attached to the handle 1 for conveying the spraying liquids through the opening 26 and a tube 25 communicates with the suction or vacuum chamber 15. The boring tool 19 also passes through the opening 26.

Reference numeral 29 (FIG. 3) indicates two slits located substantially in the frusto-conical portion of the outer shell 14 for creating a vacuum in the suction or vacuum chamber.

Flexible cable 2 is compositely driven by a reciprocating rotational motion on an arc of a chord through about 90° and by a uniform continuous rotary motion. This composite motion is integrally transmitted to the bushing 17 and also to the boring tool stem which, because it is screwed on the fixed plug 20, moves axially forward, while retaining the reciprocating rotational motion. To sum up, the reciprocating rotational motion on an arc of a chord through about 90° is unaltered on the boring tool, whereas the continuous rotary motion is converted to rectilinear translational motion.

The composite motion given to the flexible cable is provided by an electromechanical device of the present invention which is shown in FIGS. 4 and 5.

This electromechanical device comprises a gear reducing unit 30 having a shaft 31 on which a disc 32 is keyed. Two opposed electromagnets 33 are rigidly secured on the disc 32, the pole pieces of these electromagnets being effective to energize a rocker rod 34 which is pivoted at 35, and, in FIG. 5, the rocker arm is shown in closer position to the left electromagnet of the pair. The rocker rod 34 engages a pin 36 which is keyed on a disc 37. The disc 37 is carried by an idle shaft 38 which is freely rotatable about the axis of disc 32. The flexible cable 2 is fastened to said disc 37. On the fact of disc 32 opposite to that on which said electromagnets 33 are arranged, three conductive rings 39 are placed with the electric supply brushes sliding thereon.

A revolution counter 41 is operated by a pin 42 projecting from the hub carrier of said disc 32.

On alternately energizing the electromagnets by electric pulses, the rod 34 is caused to swing through an angle of about 90° and the disc 37 is also caused to rotate through about 90°. Because it is pivoted on disc 32, the rocker rod 34 is caused to rotate therewith and, as a result, provides the disc 37 with a continuous rotary motion.

The r.p.m. as provided by the revolution counter is related to the boring tool feed, thereby allowing for programming the boring operation.

According to an alternate embodiment, the substantially frusto-conical portion of the shell 14 may be separated from the substantially cylindrical portion of the shell and may be connected thereto by a resilient element enabling the position of the suction or vacuum chamber relative to the tool holder head to be changed.

Other modifications and changed may be made without departing from the spirit and scope of the present invention.