Abstract:
A contra-angled driver receives an endodontic activator to induce vibrations and/or oscillations in the activator at sonic frequencies. The driver includes a quick connect/disconnect to allow for quick and simple mounting and dismounting of the activator.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   Not Applicable. 
   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not Applicable. 
   BACKGROUND OF THE INVENTION 
   This invention relates to endodontic tools, and in particular, to a driver to vibrate an activator to enhance cleaning of root canals during an endodontic procedure. 
   Following tooth maturation, the dental pulp is harbored within the structural elements of the tooth. Frequently, and for a variety of reasons, the pulp is irreversibly injured, resulting in inflammatory and infectious conditions which often adversely affect the tooth and its supporting structures. Clinically, as an alternative to extraction, root canal treatment is performed and ideally directed towards the elimination of pulp, bacteria, and related irritants from the root canal system, followed by three-dimensionally filling the root canal space with an inert, biocompatible, dimensionally stable, filling material, such as gutta percha. Ideally, the obturation procedures will fill not just the main canal, but the fins, webs, cul-de-sacs, lateral canals, and all portals of exit between the root canal system and the tooth&#39;s attachment apparatus. 
   Central to a successful endodontic (or root canal) treatment has been the use of chemical reagents during mechanical root canal shaping procedures to completely clean all aspects of the root canal system. The chemicals used to enhance canal debridement and disinfection during cleaning and shaping procedures potentially reach all aspects of the root canal system. The most popular chemicals currently used during canal preparation to actively assist in cleaning and disinfecting include bleach, hydrogen peroxide, and chelating agents. Often, a 2%-5% solution of a clear, pale, greenish-yellow strongly alkaline solution of sodium hypochlorite (NaOCl) and ethylenediaminetetracetic acid (EDTA) are used. 
   During canal preparation, a solution of NaOCl is liberally irrigated into the root canal space where its solvent action facilitates the digestion and removal of pulp, bacteria, viruses, spores, endotoxins and other irritants generated by the microorganisms. This solution has the potential to circulate, penetrate and, hence, clean into all aspects of the root canal space. However, studies have shown that even the most thorough use of sodium hypochlorite does not remove all the material from the root canal. The walls of a root canal are comprised of dentin, which contains millions of dentinal tubules per square millimeter. Instruments used to negotiate and shape a canal cut dentin and dentin, in combination with organic substrates, forms dentinal mud. Dentinal mud, pulp, bacteria, and other related irritants have been consistently visualized histologically after cleaning and shaping procedures in the dentinal tubules and various aspects of the root canal systems. Thus, after cleaning and shaping procedures, the root canal is still covered with a film of debris, frequently described in the literature as a “smear layer.” This “smear layer” includes dentinal mud and/or organic debris, including the irritants noted above. 
   After cleaning and shaping, the root canal has been traditionally filled with gutta percha and a root sealer. However, if the smear layer or film is not adequately removed from the root canal, the smear layer can compromise the filling and sealing of the root canal system. If obturation is incomplete then the root canal space is predisposed to bacterial leakage and failure. Post-treatment failures attributable to leakage are common and require endodontic retreatment of the tooth or extraction. Thus, for a complete and thorough cleaning, this smear layer or film should be removed. To address the smear layer, practitioners use a weak acid or surfactant, such as 17% EDTA, in an effort to remove the smear layer. Typically, the root canal is flushed with EDTA, or other final rinse solutions, to accomplish this. Traditionally, some practitioners have used a metal root canal file or a cannula to activate the solution and enhance the performance of the EDTA. These devices may be used manually or mounted in an ultrasonic handpiece to produce vibrations and fluid movement. As an example, even when a file is used, it is impossible to ensure that the file is brought into contact with the complete surface of the root canal, and hence it is difficult to ensure that substantially all of the smear layer has been removed. Regrettably, the use of ultrasonically driven metal instruments has frequently led to iatrogenic events, such as broken instruments, ledges in the wall of the root canal preparation, or even perforation of the root canal. Hence the use of such instruments is not desirable. 
   U.S. Pat. No. 6,179,617 and Published U.S. application Ser. No. 20040214135, both of which are incorporated herein by reference, disclose an endodontic brush for use in removing the smear layer. A brush can work well to remove the smear layer from the main path of the root canal. However, the brush bristles may not extend into the fins, webs, cul-de-sacs, anastomoses, lateral canals, and portals of exit between the root canal system and the tooth&#39;s attachment apparatus. Hence, while the brush may effectively remove the smear layer from the main canal, these fins, webs, lateral canals, etc. may still contain pulp, bacteria and related irritants, which may then compromise sealing the canal. 
   Currently, ultrasonically activated endodontic instruments, are used, at times, to enhance the cleaning of a shaped canal prior to three-dimensional filling. Such instruments include, for example, the BUC® tips sold by SybronEndo, the ProUltra™ tips sold by Dentsply, and the CPR® tips sold by Obtura. These metal instruments are connected to an ultrasonic driver. The tips generally are contra-angled tips. For the ultrasonic energy to efficiently pass through the contra-angled portion and along the overall length to the tip, the instrument is required to be securely connected to the driver. To this end, these instruments are all connected to the drive by threads which require a wrench to fully and securely connect the instruments to the drive. Multiple tips may be used in a single procedure. As can be appreciated, the need to use a wrench to connect a tip to the driver and to then disconnect the tip from the driver increases the time involved in mounting and dismounting of the tips. Because these instruments oftentimes have abrasive coatings and additionally cut toward their tips, they should not be used to remove the smear layer. 
   I have found that by vibrationally driving a non-cutting activator, the cleaning solution can be made turbulent, inducing cavitation at the end of the activator and acoustic streaming along the length of the activator, thereby enhancing the removal of the smear layer from both a shaped root canal, and importantly, from the fins, webs, lateral canals, etc. commonly comprising root canal system anatomy. 
   BRIEF SUMMARY OF THE INVENTION 
   Briefly stated, a driver is provided to induce vibration and drive an endodontic activator. In an illustrative embodiment, the driver comprises a body having a handle and a neck. As seen in the drawing figures, the driver body can have a contra-angle design. Illustratively, the driver is cordless and contains rechargeable batteries as a power source. The driver, however, could be corded, or be configured to accept non-rechargeable batteries. 
   A driven member is mounted in the body for pivotal motion about an axis. The driven member comprises a mounting ring, a mounting arm and a connecting arm. The housing comprises a pair of opposed arms at the end of the handle neck, and the arms define a gap. The driven member is mounted in the gap. A rod passes between the handle arms, and the driven member mounting ring is journaled on the rod. The mounting arm and connecting arm can define an angle of between about 80° and about 90°. 
   A driving means is mounted within the handle and is operatively connected to the driven member to induce vibratory and/or oscillatory motion in the driven member. In the illustrative embodiment, the driving means comprising a block which is rotated about an axis of rotation. The block defines a pocket on an end surface which receives the driven member connecting arm. The pocket is off-set from the axis of rotation so that rotation of the block member will create oscillatory motion in the driven member connecting arm, which is passed onto the driven member mounting arm, such that the driven member mounting arm will vibrate. The block can be rotated, for example, by a motor. 
   When activated, the driver induces vibrations/oscillations in a sonic frequency range (i.e., less than about 15 kHz). The driver includes a speed control to enable the oscillatory speed of the endodontic activating tip to be selectively changed and operate at different speeds or frequencies. The speed control can allow for the selection of a speed along a continuum of speeds between a high speed to a low speed. Alternatively, the speed control can have, for example, three set speeds (i.e., high, medium and low). 
   The endodontic activator includes a mounting block defining a pocket which is shaped complimentarily to an end of the driven member mounting arm and which is sized to be frictionally and removably received on the driven member mounting arm. An activating tip extends from the mounting block. The size and shape of the endodontic activator mounting block allows for the activator to be mounted to the driven member mounting arm (and hence to the driver) quickly, easily, and without the use of tools. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       FIG. 1  is a bottom perspective view of an illustrative embodiment of a driver of the present invention; 
       FIG. 2  is a top perspective fragmentary perspective view of the driver; 
       FIG. 3  is a side elevational view of the driver; 
       FIG. 4  is an exploded perspective view of the driver; 
       FIG. 5  is a cross-sectional view of the driver with an activator mounted thereto; 
       FIG. 6  is an end elevational view of the driver with the cover removed showing the mounting of a vibrational member to the tip of the driver; 
       FIG. 7  is a cross-sectional view taken along line  7 - 7  of  FIG. 6 ; 
       FIG. 8  is an enlarged cross-sectional view of the forward end of the driver showing the mounting of a driven member in the driver and the connection of an activator to the driven member; and 
       FIG. 9  is an enlarged cross-sectional view showing the activation and control switches of the driver. 
   

   Corresponding reference numerals will be used throughout the several figures of the drawings. 
   DETAILED DESCRIPTION OF THE INVENTION 
   The following detailed description illustrates the invention by way of example and not by way of limitation. This description will clearly enable one skilled in the art to make and use the invention, and describes several embodiments, adaptations, variations, alternatives and uses of the invention, including what is presently believed to be the best mode of carrying out the invention. Additionally, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. 
   An illustrative embodiment of a driver  10  of the present invention for driving an endodontic activator  12  is shown generally in  FIGS. 1-3 . The activator  12  is preferably an activator such as is described in co-pending application Ser. No. 11/104,678, filed Apr. 13, 2005, entitled “Apparatus And Method For Preparing A Root Canal” and which is incorporated herein by reference. The activator  12  comprises a guard  12   a , a connection block  12   b  defining a pocket, and a tip  12   c  ( FIG. 4 ). The driver  10  comprises a handle  14  and a neck  16 . The driver or handpiece  10  is a contra-angled handpiece, and hence the handle  14  and the neck  16  define an angle α ( FIG. 3 ) of about 15° to about 30°, and preferably about 25°. The activator  12  is mounted to the driver, such that the activator forms an angle β of about 80° to about 85° with the axis of the neck  16 . 
   The handle  14  and neck  16  are both hollow and in combination define a housing for the elements which drive the activator  12 . The housing members  14  and  16  are made from an FDA approved plastic, such as ABS and/or polycarbonate. The housing members could be made from any other desired material. 
   The handle  14  is comprised of a body  20  and a forward section or connector  22 . The handle body  20  is closed at its back end  20   a  and opened at its forward end  20   b  and defines a battery compartment. Externally, the handle body is provided with textured rubber grip areas  24   a,b  on opposite sides of the handle body. These grip areas can be co-molded with the handle body  20  and provide non-slip areas for a practitioner to grasp the driver  10 . 
   A battery mount  26  is received in the battery compartment defined by the handle body  20 . The battery mount  26  includes a main section  26   a  which forms a cradle  26   b  sized and shaped to receive a battery  28 . Contacts  30  are mounted in pockets  26   c  located at opposite ends of the cradle  26   b . A stem  26   d  extends from the bottom of the mount  26 . A charging unit  32  can be placed about the stem  26   d  to allow for the use of rechargeable batteries. If a charging unit  32  is provided, the handle body  20  will be provided with appropriate means to allow for electrical connection of the body to a source of electricity to enable the battery  28  to be recharged. Such connection means can include external contacts, in which case the driver would be received in a charging base which, in turn, is connectable to a source of electricity. Alternatively, the connection means can comprise a socket which receives a connector end of a charging adapter having prongs enabling the adapter to be plugged directly into an electrical outlet. In either situation, such connection means are well known to those skilled in the art and are not described herein. Alternatively, handle body  20  can be configured to allow for replacement of the batteries. This would allow for replacement of rechargeable batteries or for the use of non-rechargeable batteries. As can be appreciated, the use of a battery operated driver enables the driver to be cordless. As another alternative, the driver could be configured to be a corded driver. In this case, an electrical cord would be provided. Such a cord could have a plug on its end for connection to a wall outlet or other electrical outlet. As a further alternative, an electrical cord could be hardwired to a control panel. 
   The forward end of the mount  26  is provided with circumferential grooves  26   e  which receive O-rings  34 . The mount  26  and the O-rings  34  are sized such that the O-rings form a fluid-tight seal between the internal surface of the handle body  20  and the mount  26  at the forward end of the mount  26 . When the mount  26  is received in the handle body  20 , the O-rings  34  will be approximately flush with the opened end  20   b  of the handle body  20 . A bracket  26   f  extends from the end of the mount  26  forwardly of the O-ring grooves  26   e . When the mount  26  is received in the handle body  20 , the bracket  26   f  will extend from the forward end  20   b  of the handle body  20 . 
   A switch fixture  36  is received in the bracket  26   f . The switch fixture  36  is generally rectangular in shape, having first and second sides. On one side, the switch fixture  36  includes two sets of opposed arms  36   a  which snappingly receive and hold a spring biased button  38 . The button  38  is movable radially with respect to the handle (i.e., generally perpendicularly relative to the switch fixture  36 ). A control board  40  and a sliding switch  42  are received and supported on the opposite side of the switch fixture  36 . 
   The switch fixture  36  and the associated button  38 , control board  40  and switch  42  form a control assembly which is enclosed by the handle forward section  22 . The handle forward section  22  includes a flexible membrane  44  ( FIG. 2 ) on its upper surface which is aligned with the button  38 . The membrane  44  covers an opening in the handle forward section and is sealed with respect to the opening to prevent the passage of fluid between the handle forward section  22  and the membrane  44 . The membrane  44  can, for example, be co-molded with the connector  22  or otherwise bonded to the handle forward section  22  to form this seal. The membrane  44  is shown to be partially sunken to form a thumb receiving depression  44   a . By pressing on the membrane  44 , the button  38  will be moved radially to activate or deactivate the driver. 
   A speed selector assembly  50  is received in an opening on the opposite side of the handle forward section  22  from the membrane  44 . The speed selector  50  is operatively connected to the speed switch  42  to control the position of the speed switch  42 . The speed selector assembly  50  includes a cover  52  sized to be received in and to seal with a second opening in the handle forward section  22 . The cover  52  forms a recess  53  ( FIG. 1 ) having an elongate slot formed therein. A switch block  54  is received in the cover recess  53  and is sized such that the outer surface of the block will be flush with the outer surface of the handle forward section  22 . The block  54  includes a rib  56  which extends through the slot in the switch cover  52 . A hole  57  extends through the block  54  behind the rib  56 ; and a push button  58  extends through the hole. 
   On its inner surface, the switch cover  52  includes a pair of opposed guides  59  which are on opposite sides of, and extend generally parallel to, the cover slot. A switch block fixture  60  is positioned between the switch cover guides  59 to be movable axially between the guides  59 . The switch block fixture  60  is operatively connected to the switch block  54 , and is moved axially by movement of the switch block  54 . A pole  62  extends from the inner surface of the switch block fixture  60 . The pole  62  can, for example, be formed from a screw which is threadedly connected to the switch block fixture. The pole  62  is sized to engage the sliding switch  42 . 
   As can be appreciated, when the operator moves the switch block  54 , the movement of the switch block will be transferred to the sliding switch  42 . The engagement of the sliding switch  42  and the control board  40  is one such that as the switch is moved relative to the control board  40 , the electrical output from the control board is adjusted. The push button  58  maintains the switch block  54 , and hence, the sliding switch  42 , in a desired position relative to the control board. In the illustrative embodiment shown, the switch is configured to provide for three discrete output levels. Although a slide is disclosed to enable the electrical output from the control board to be changed, other mechanisms can be used as well. For example, a thumb wheel could be used, and the position of the thumb wheel could be determined using any desired means to determine the position of the wheel, and hence the desired output from the control board. Alternatively, a button, or a plurality of buttons could be used. If one button is used, each time the button is pressed, the output could change between a plurality of preselected, discrete outputs. If two buttons are used, one button could be an output increasing button and the other could be an output decreasing button. In this case, the output would increase or decrease based upon the amount of time the button is depressed. Further, a plurality of buttons could be used, in which case, each button would represent a discrete output. 
   A motor mount  64  is received in the forward end of the handle forward section  22 . The motor mount  64  includes a body  65  and a base portion  66  at one end of the body  65 . A ring or flange  67  separates the body  65  from the base portion  66 . An O-ring  68  is received in a groove on the base portion  66 . The base portion  64  is sized and shaped to be frictionally received in the forward opened end of the handle forward section  22  with the ring or flange  67  resting on the inner step  22   b . The O-ring  68  forms a fluid tight seal between the motor mount base portion  64  and the handle forward section  22  below the step  22   b . As can be appreciated, a slight gap will be formed around the motor mount body  64  and the handle forward portion step  22   a . 
   A pair of opposed arms  70  extend forwardly from the forward end of the motor mount  64 . The motor mount  64  is received in the handle forward section  22  such that the arms  70  extend beyond the forward end of the handle forward section  22 . The arms  70  are flexible and include inwardly extending fingers at the ends thereof. A motor  74  is received in the motor mount  64 . The motor mount arms  70  are sized such that the arm fingers extend over the end of the motor  74 . The motor  74  will therefore be securely held in the motor mount  64  by the arms  70 . The flexibility of the arms  70  facilitates insertion of the motor  74  between the arms. 
   The motor  74  is an electric motor having an output shaft  76 . As is known, the driver  10  includes wires which electrically connect the battery  28 , the control board  40 , the on/off button  38 , the speed switch  42  and the motor  74 . Thus, the motor can be activated by pressing of the button  38  and the motor speed will be controlled by movement of the speed switch  42  by means of the switch block  54 . The speed switch can have discreet settings such that the motor is operated at a determined number of set speeds (i.e., low, medium and high). Alternatively, the speed switch can be continuously variable so that the motor can be operated at any desired speed along a continuum of speeds from a high speed to a low speed. 
   An ellipse block  80  is fixed to the motor output shaft  76  to be rotated thereby. The ellipse block  80  comprises a base  82  having a bore in the bottom thereof sized to fit over the motor output shaft  76 . The ellipse block base  82  can be secured to the output shaft  76  in any desired manner to ensure that the ellipse block will be rotated by rotation of the output shaft  76 . For example, a set screw can be used or the bore in the ellipse block base  82  can be keyed to the shaft  76 . The ellipse block  80  includes a body  84  at the forward of the base  82 . A hole  86  is formed in the end surface of the body  84 . As seen, the hole  86  is offset from the axis of the motor shaft  76 . Hence, the hole  86  will move in an orbital or eccentric pattern as the ellipse block is rotated by the motor  74 . 
   The driver neck  16  fits over the motor  74  and motor mount  60 . The driver neck  16  includes an axially extending generally circumferential lip  16   a  which is received in the gap between the motor mount  64  and the handle forward section  22 . The forward end of the neck  16  is provided with a pair of opposed arms  90  defining a slot or gap  91  therebetween. The arms  90  define a tip to the neck  16 . As seen, the arms have axially sloped and circumferentially curved outer surfaces, such that the neck tip is generally in the shape of a blunt or flattened cone. An opening  92  is formed in each of the arms  90 . The openings  92  are aligned with each other and extend generally perpendicularly to the gap between the arms. At the base of the arms  90 , the neck  16  is stepped, as at  16   b,c ; and each step  16   b,c  defines a shoulder. 
   A driven member  100  is mounted in the neck tip. The member  100  comprises a mounting portion  102  in the form of a ring. The mounting portion is sized to fit in the gap  91  between the neck arms  90 . A bushing  104  is received within the mounting portion  102 , and a pin, axle or rod  106  extends through the bushing and into the opposed openings  92  in the arms. Hence, the pin  106  defines an axis about which the member  100  can pivot. Importantly, the mounting portion  102  is narrower than the gap between the arms  90 , such that the portion  102  (and the member  100 ) can move freely relative to the arms  90 . 
   A connecting arm  108  extends downwardly from the mounting portion  102  into the neck  16 . A connection member or ball  110  is formed at the free end of the connecting arm  108 . The connecting arm  108  is sized such that the ball  110  is received in the hole  86  of the ellipse block  84 . As seen in  FIGS. 4 ,  5  and  8 . the connecting arm  108  has an outer surface between the mounting portion and the ball that is substantially straight and uninterrupted. A mounting arm  112  extends from the mounting portion  102  and forms an angle with the connecting arm of between about 80° and about 90°. The angle can be, for example, about 82°. The mounting arm  112  includes a first part  112   a  which is generally cylindrical and a second part  112   b  which has flattened sides. As seen in  FIGS. 6 and 8 , the mounting arm  112  has a length such that it extends beyond the outer surfaces of the neck  16 . 
   A cover  114  is received over the tip of the neck  16 . The cover  114  is made from a flexible material, such as silicon rubber. The cover includes a body  114   a  and a nose  114   b . The cover body  114   a  is sized and shaped to snugly fit over and about the arms  90  of the sleeve  16 . The nose  114   b  is positioned on the cover body  114   a  to be aligned with the gap between the arms  90  and to be in the plane of the arm holes  92 , such that the mounting arm  112  of the driven member  100  will extend through the nose  114   b . The nose  114   b  is cylindrical in shape, and is sized to fit around the first part  112   a  of the driven member mounting arm  112 . The cover  114  is sized at its bottom end to form a seal with the neck  16 , at the step  16   c.    
   The driver  10  further includes a cap  116  which encases the cover  114 . The cap is a two piece cap and comprises a back portion  116   a  and a front portion  116   b . The front and back portions of the cap snap together. A nose  118  extends from the cap front portion  116   b . The driven member mounting arm  112  extends through the cap nose  118  so that an activator can be mounted on the mounting arm  112 . 
   As shown in the drawings, and as described above, and as described our co-pending application Ser. No. 11/104,678, which is incorporated herein by reference, the activator  12  is includes guard  12   a , connection block  12   b , and activating tip  12   c . The cover nose  118  and the activator guard  12   a  are respectively sized and shaped such that the guard  12   a  covers the front of the cover nose  118 . While the guard  12   a  may not form a seal with the nose, the size and shape of the guard relative to the cover nose will help prevent aerosoled, splattered, or sprayed fluids from entering the tip of the driver. The activator connecting block  12   b  defines a pocket or cavity which is sized and shaped to be snuggly received over the shaped end  112   b  of the driven member mounting arm  112 . The activator  12  is made from a flexible, non-metallic, non-cutting material, and can be made from plastic, nylon, or an aromatic polyamide (such as Kevlar®). The flexibility of the activator (and of the activator connection block  12   b ) allows for the connection block  12   b  to be expanded slightly when the block is mounted onto the driven member mounting arm  112 . The mounting arm  112  and the connection block pocket have very similar dimensions. Thus, the activator will be held on the mounting arm by frictional forces. Therefore, tools are not required to connect the activator to, or remove the activator from, the driver  10 . 
   In operation, when the driver  10  is activated by means of the button  44 , the motor  74  will rotate the ellipse block  80 , causing the ellipse block hole  86  to orbit about the motor shaft  76 . The orbital motion of the hole  86  will be transferred to the driven member connecting arm  108  through the connection between the driven member connecting arm  108  and the ellipse block hole  86 . Hence, the bottom or baii  110  of the driven member  100  will be driven in a circular or orbital path. The connecting ring  102  is loosely mounted on the bushing  104  and pin  106 . Further, the bushing and pin are made of materials which will not significantly dampen the vibratory motion induced into the driven member&#39;s connecting arm  108 . Hence, the vibratory motion of the connecting arm  108  is transferred to the driven member mounting arm  112 . The vibratory motion is then transferred to the activator  12 . 
   As noted in the above noted co-pending application, the activator is made from a very flexible material. Hence, the vibrations that are passed to the activator essentially cause the activator tip  12   c  to oscillate or vibrate. When the activator tip is placed within a root canal filled with fluid, activation of the driver will cause tip to vibrate within the canal. The vibration of the tip will result in cavitation and acoustic streaming resulting in turbulence of the fluid. The vibrating tip will engage the surfaces of the prepared root canal to facilitate removal of the smear layer within the root canal. Further, the fluid turbulence will reach into the lateral anatomy of the root canal to also facilitate deep lateral cleaning. 
   The activator tip is made from a non-cutting non-metallic material. Hence, vibration of the tip within the root canal will not damage the root canal—it will not create any ledges or otherwise alter the shape of the already prepared root canal. 
   The motor  74  operates such that the tip  12  will vibrate at sonic frequencies (i.e., less than 15 KHz). The speed switch can be used to adjust the speed of the motor, and hence the rate at which the tip  12  vibrates. As noted above, the switch in the illustrative embodiment provides for three discrete outputs, which drive the activator of frequencies of 2, 6, and 10 kHz. These speeds can be changed if desired to be different speeds, and, the switch assembly can provide for two, three, four or more discrete speeds. Alternatively, the speed switch can be one which allows for a continuum of speeds from a high speed to a low speed. 
   In the ultrasonically activated endodontic tips such as are noted above in the background which are used to primarily cut dentin or vibrate against metal objects, the vibrational energy passed into the tip must pass through a bend or curve in the instrument itself. Thus, for the cutting end of the tip to vibrate at a proper speed, the tip must be tightly mounted to the driver. Hence, such cutting tips require that the tip be threaded onto the tool and that wrenches be used to tighten the tip to the driver. However, in the instant application, the vibrational energy does not need to be transmitted about any bends after it has been transferred to the activator  12 . Hence, the activator  12  need not be so tightly connected or mounted to the driver&#39;s mounting arm  112 ; and, the activator  12  can be frictionally held by the mounting arm  112 , as noted above, and connected to, and disconnected from, the driver without the use of tools. In fact, in the design shown, the activator is frictionally fitted onto the mounting arm  112  as noted above, and hence can easily be slipped on and slipped off of the mounting arm  112 . 
   Although the use of rotating ellipse block is shown as the means for inducing vibrational motion in the driven member  100 , other means can be used as well. For example, the end of the connecting arm  108  can be provided with a magnet, and this magnet can be adjacent an electromagnet. The electromagnet can then be alternatively energized and de-energized (or its polarity can be continuously alternated) to thereby induce vibrational motion in the connection member  108 . Alternatively, such a magnet at the end of the connecting arm can be surrounded by a plurality of electromagnets which are energized to induce motion in the end of the connection member (much in the same way a motor stator causes a motor rotor to rotate). 
   As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. For example, although the driver is shown and described to be cordless, the driver could be made to be a corded driver. Additionally, although the driver is shown and described to be contra-angled, the driver could be a straight. Further, the driver could drive the activator at other speeds than disclosed above, and, hence, the activator could be driven at ultrasonic speeds in addition to sonic speeds. If the activator is to be driven ultrasonically, the vibration inducing means may be changed from that disclosed above to a piezoelectric system or a magnetorestrictive system. These examples are merely illustrative.