Abstract:
An ultrasonic instrument includes a tip portion, a transducer configured to convert electrical energy into vibrational energy, an acoustic transformer interconnecting the transducer and the tip portion, and a grip portion disposed at least partially about the acoustic transformer. The grip portion is coupled to the acoustic transformer via a resilient nodal coupling at a nodal region of the acoustic transformer. The resilient nodal coupling is configured to provide rotational and axial stability to the acoustic transformer.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of and priority to U.S. Provisional Patent Application No. 61/537,315, filed on Sep. 21, 2011, and U.S. Provisional Patent Application No. 61/559,946, filed on Nov. 15, 2011, the entirety each of which is incorporated by reference herein for all purposes. 
     
    
     BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present disclosure relates to ultrasonic tools and, more particularly, to an ultrasonic tool, or insert, for use by dental professionals for dental treatments and procedures. 
         [0004]    2. Background of Related Art 
         [0005]    Ultrasonic dental tools, or inserts, generally include four basic parts. The primary part comprises a laminated stack of a magnetostrictive material, which is activated at its frequency of resonance to generate sufficient mechanical power. The second part is a specially shaped tip that makes contact with the treatment area. This tip provides access and adaptation to the treatment area. The third part is an acoustic transformer, often referred to as a connecting body, which connects the laminated stack to the tip. The fourth part is a grip, which allows the practitioner to hold and maneuver the insert during use. 
         [0006]    Each of these building blocks for the insert has an important role in the operation of the insert. The stack provides the necessary power to drive the tip. The acoustic transformer matches the impedance of the stack to the tip, provides amplification of the mechanical motion generated by the stack, and delivers coolant and lavage to the tip. The tip transfers the mechanical motion to the treatment area, which is often a tooth or root surface. It also directs the lavage or coolant provided by the connecting body. The grip not only allows the practitioner to hold the insert but is a key component since it attaches to the acoustic transformer. It is therefore critical that the grip connect at a nodal point for the motion along the length of the acoustic transformer. Attachment to a point not on the node will dampen the motion and reduce the available power at the tip of the insert. 
         [0007]    Cavitron® Corporation introduced ultrasonic inserts to the dental market in the late 1950&#39;s. The first inserts were called “P” types to differentiate them from the cutting inserts first used for cavity preparation. Similarly as used today, the basic structure and design of these first inserts included four basic components: a laminated stack of a magnetostrictive material, a working tip, an acoustic transformer or connecting body that connects the tip to stack, and a grip allowing the practitioner to hold the insert during use. 
         [0008]    These original Cavitron® designs adapted a surgical steel tube to deliver water to the treatment area. Straight Permanickel® laminations were used to generate the mechanical energy. An acoustic transformer amplified the mechanical motion generated by the stack, and a metal grip was attached to the connecting body using a compressed O-ring. 
         [0009]    Over the years, improvements have been in the areas of water delivery to the treatment area. U.S. Pat. No. 3,930,173 to Banko and U.S. Pat. No. 5,567,153 to Foulkes et al. describe examples of the use of non-concentric holes in the tip of the insert. A swivel feature that allowed the practitioner to more easily rotate and adapt the tip along the line angles of teeth is described in U.S. Pat. No. 6,716,028 to Rahman et al. This design forced a compromise between the ease of rotation (generally rotational torque below 1 in-lb.) and leakage. At lower torque levels, the risk of coolant water leakage at the point of rotation was increased. Some designs utilize the slippage of the O-ring that seals the insert in the handpiece. These designs use a traditional toroid O-ring that seals both the handpiece-insert interface and provides a low torque rotation. They typically allow rotation within the gland area of the O-ring but are at the mercy of O-ring quality, dimensional tolerances of the O-ring, and handpiece dimensions to provide a good seal over all operating conditions. 
         [0010]    Early inserts also had the disadvantage of loosening of the attachment of the grip to the insert after several sterilization cycles. Retightening was possible but alignment of the water tubing while retightening was problematic. In addition, the tightness of the capture mechanism often resulted in instability of the grip in both the lateral and longitudinal planes. Later designs used surface indentations to minimize loosening, but these designs did not address the problems of rotational and axial movement of the grip during use. U.S. Pat. No. 3,956,826 to Perdreaux describes a method of capturing the connecting body inside a cavity in a resin grip. While this eliminates rotational and axial instability, it results in a hard mount of the connecting body at the nodal point. The end result is an improvement in the stability of the grip but degradation in the tip motion caused by the hard mounting of the grip to the connecting body. A hard mount also increases the transfer of ultrasonic energy from the connecting body to the grip. 
         [0011]    The original stack configuration for the Cavitron designs was a flat lamination without any added rigidity either along the length of the stack or in the cross-section. Some manufacturers added a “c” shape to the stack but this added little rigidity to the stack assembly, while other manufacturers added a “v” shape to the stack and glued the laminations together. While this approach added rigidity to the stack, bend angles less than 100 degrees introduced increased stress to the laminations and moved the center of gravity of the stack assembly off the concentric line of the stack-connecting body junction. 
         [0012]    The stack assembly in typical ultrasonic dental inserts is brazed at both ends. The distal end has an end-ball attached to hold the ends of the laminations together and provide a rounded surface to minimize any damage to the handpiece during insertion and removal. U.S. Pat. No. 5,980,251 to Sullivan et al., for example, describes a method of creating a conductive connection of brazing material (silver solder) at both ends of the stack. First, this is counterproductive in that it increases the losses in the stack assembly during use. Second, it decreases the frequency of resonance of the stack assembly because of the lower sound velocity of the brazing material compared to the Permanickel® laminations. Third, the phase shift of the feedback signal in ultrasonic systems is adversely affected, especially with regard to those systems employing motional or velocity feedback. 
       SUMMARY 
       [0013]    In accordance with the present disclosure, an ultrasonic dental tool, or insert, is provided. The insert includes a notch on both sides of the distal end of the laminated stack assembly. The notches are secured in any suitable fashion, e.g., using a high temperature heat shrinkable material. 
         [0014]    In embodiments, the distal end of the stack includes an end cap. The end cap may be a molded or machined high temperature resin that provides mechanical stability of the laminations during ultrasonic activation and sterilization cycles. 
         [0015]    In embodiments, a non-metallic or low conductivity metal rivet component secures the laminations in the stack assembly. The component is secured in a small diameter hole near the distal end of the stack assembly by, for example, staking, snap locking, gluing, ultrasonic welding, etc. 
         [0016]    In embodiments, a rigid or semi-rigid tube encloses the laminations in the stack assembly. The tube may be constructed from a high temperature resin and/or may be formed via extruding or molding. This encasement, e.g., the tube, may further include a nodal support for the laminations at their midpoint. 
         [0017]    In embodiments, a resilient material captures the connecting body in the nodal area. For example, a “soft mount” configuration for the grip may be provided, while also providing stability with minimal axial and rotational movement during use. 
         [0018]    In embodiments, the laminated stack assembly may be recess mounted to the mesial end of the connecting body. Such a mounting allows for concentric mounting of the stack assembly to the connecting body, resulting in minimum brazing material on the lateral sides of the stack assembly. 
         [0019]    In embodiments, the laminations in the stack assembly define a pre-determined shape that provides adequate stiffness to the laminations to avoid deformation during use and handling of the insert. 
         [0020]    In embodiments, the insert is rotatable 360 degrees during use with minimal torque. The use of a multi-diameter sealing component is also contemplated. 
         [0021]    In embodiments, precise bending of the insert tip can be achieved at the location of the nodal point supports in a bending fixture. 
         [0022]    Particular advantages and features of the above-mentioned and other embodiments of the present disclosure are described below. To the extent consistent, any or all of the above-mentioned embodiments (or any other embodiments) may be used in conjunction with any or all of the other embodiments described herein. 
         [0023]    A typical stack comprises laminations of a Ferro-magnetic (magnetostrictive) material ranging from 0.007 to 0.010 inches thick. The industry standard size in dentistry is 0.010 inches. Thinner laminations are often used at frequencies higher than 25 kHz to reduce eddy-current losses. The laminated stack assemblies of an ultrasonic dental tool have the capability to outlast the tip and connecting body assemblies by a factor of 10 to 20 times. The endurance of the stack assemblies however, is limited by handling damage. The present disclosure provides a stack having both improved electro-mechanical characteristics and durability. In particular, the multiple angle bend of the stacks of the present disclosure, e.g., in the form of a “Z” bend or a “W” bend, provide both lateral and longitudinal rigidity to the laminations in the stack assembly without introducing excessive stresses along the bends because of the large bend angles. Bend angles are typically between 100 and 150 degrees. The basic geometry of the assemblies of the present disclosure place the center of the assembly on or close to the centerline of the connecting body-stack junction. 
         [0024]    Typically, even slight bending of the stacks will result in a loss in mechanical output of the insert. A new stack that is bent by handling and then re-straightened will in most cases perform like an old insert with a tip worn beyond the recommended 2 mm length. The present disclosure provides a rigid or semi-rigid tubing to protect the stack during all phases of usage. The tubing can be an extruded or a machined piece with an internal dimension that approximates the diagonal dimension of the stack assembly. The mesial end of the tubing is configured to facilitate mounting the insert into a handpiece, provides a seal for the insert-handpiece interface, and allows for relatively low torque rotation of the insert assembly within the handpiece. In this configuration, the laminations on the stack assembly are flat and the distal ends of the laminations are not bound together. Further, in this configuration, a molded shell may be used in place of the tube. The advantages of the shell are the versatility of having several cross-sectional diameters and the addition of a nodal support for the stack assembly. 
         [0025]    Currently, applications requiring insertion and removal from a handpiece often have interference due to the size and shape of the brazed end-ball. The present disclosure provides configurations that avoid the pitfalls of brazing the distal ends of the laminations together. This eliminates the possible interference fit into a dental handpiece due to an oversize endball. The use of a molded end cap, a heat shrinkable material, or a low conductivity pin improves assembly time and reduces the handling cost of the stack assembly without creating interference with the feedback system of the ultrasonic device. 
         [0026]    Complete dental tools are customarily referred to as “half lambda” tools because they comprise two parts, where each part consists of a one-half wavelength (half lambda) as determined by the frequency of resonance of the materials and the physical lengths of the components. These tools are free to move at both ends and have two centrally located longitudinal nodal points. By definition, the longitudinal motion at the nodes is zero. Any contact of the tool off the nodal points will result in damping of the motion. Accordingly, the present disclosure provides a dental tool that mounts the grip to the connecting body with a resilient nodal mount (referred to herein as a “soft mount”). One of the key features of this configuration is that it minimizes the loading effects caused by the shifting of the nodal point during loading of the tool&#39;s tip. This configuration also minimizes the transfer of ultrasonic energy to the grip because of the high impedance presented by the resilient nodal support. Several variations of the soft mount are described in greater detail hereinbelow. For example, in embodiments, protrusions are located on the connecting body in the nodal region. An extruded resilient material is placed onto these protrusions and the assembly is placed into the insert grip. Alternatively or additionally, in embodiments, commercially available resilient O-rings or similar components may be utilized to provide a soft mount between the connecting body and the grip. The capture mechanisms for the nodal supports can be machined or molded. 
         [0027]    Precise bending of the tips on the connecting body assemblies requires a reliable registration point in the bending fixtures. Current insert designs rely on the edge of the tip shank, but these points are located on radii and require the operator to use an approximate reference point. The present disclosure uses nodal protrusions on the connecting body assembly to precisely register the connecting body in a bending fixture. This configuration allows for the interchanging of bending tool inserts for bending of different tip styles and lengths of the assemblies. 
         [0028]    The grip of an insert tool provides the practitioner the ability to grasp and maneuver the tool during use. The present disclosure provides a configuration that facilitates the rotation and adaptation of the working tip along the line angles of the tooth. One of the limitations for all resin grips is the small cross-sectional area in the gland area of the O-ring. This small cross-section causes problems in fluid flow across this area during molding. The thin section also creates challenges in welding the molded grips together. To account for this, the present disclosure provides a flat seal with or without raised circumferential rings, which allows the use of a thicker cross-section in the insert grip gland area. The mounting area can be shaped to allow smooth interfaces for the seal of the insert and a profile for the center of the seal that enhances both the ability to seal the insert-handpiece interface and provide a low torque rotation. 
         [0029]    Dental handpieces typically have a cross-section that allows for mounting of a dental tool or insert with minimal space allowed for water delivery to the insert. When the brazed joint of the stack-connecting body is too large, it impedes the entry of the insert into the handpiece. This can result in reduced mechanical output at the tip due to the damping effect when a portion of the stack assembly is loaded off the nodal point. It can also restrict the water flow to the insert resulting in ejection of the insert due to backpressure in the handpiece. This is aggravated with the use of the aforementioned toroid O-ring in rotational designs. The present disclosure provides a connecting body with a recessed area that self-aligns the connecting body and stack assembly during assembly. A further feature of this configuration is that it provides an area for a braze fillet, thereby minimizing the possibility of excessive braze material at the joint. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS: 
         [0030]      FIG. 1   a  is a side view of a connecting body provided in accordance with the present disclosure and including two protrusions at the nodal point with a resilient material placed over the protrusions; 
           [0031]      FIG. 1   aa  is a transverse, cross-sectional view of  FIG. 1   a  taken at the nodal point; 
           [0032]      FIG. 1   b  is a top view of the connecting body of  FIG. 1   a  illustrating the positioning of the resilient material over the protrusions; 
           [0033]      FIG. 1   bb  is a transverse, cross-sectional view of  FIG. 1   b  taken at the nodal point; 
           [0034]      FIGS. 2   a  is a side view of the connecting body of  FIG. 1   a  shown captured by the insert grip; 
           [0035]      FIG. 2   b  is a top view of the connecting body of  FIG. 1   a  shown captured by the insert grip; 
           [0036]      FIG. 3   a  is longitudinal, cross-sectional view of a bending tool using nodal supports to register the connecting body for precise bends; 
           [0037]      FIG. 3   b  illustrates exemplary bending geometry of the bending tool of  FIG. 3   a;    
           [0038]      FIG. 4   a  is a transverse, cross-sectional view of a multi-level seal for the insert interface with the dental handpiece; 
           [0039]      FIG. 4   b  is a top view of the insert and dental handpiece including the multi-lever seal of  FIG. 4   a  disposed about the interface therebetween; 
           [0040]      FIG. 5  illustrates laminations forming a stack assembly mounted in a countersink on the connecting body of  FIG. 1   a;    
           [0041]      FIGS. 5   a  and  5   b  are transverse, cross-sectional view of various configurations of the laminations forming the stack assembly; 
           [0042]      FIG. 6   a  is an illustration of a tubular member that mounts over the laminated stack assembly; 
           [0043]      FIG. 6   aa  is a transverse, cross-sectional view showing the tubular member mounted over the laminated stack assembly; 
           [0044]      FIG. 6   b  is an illustration of a two-piece molded sheath that mounts over the laminated stack assembly; 
           [0045]      FIG. 6   bb  is a transverse, cross-sectional view showing the two-piece molded sheath mounted over the laminated stack assembly; 
           [0046]      FIG. 7  is a top view of a notches laminated stack assembly; 
           [0047]      FIG. 7   a  is an exploded, side view of the notched laminated stack assembly of  FIG. 7  and an O-ring configured for engagement within the notches of the laminated stack assembly; 
           [0048]      FIG. 7   b  is an exploded, side view of another embodiment of a notched laminated stack assembly and a cap configured for engagement about an end of the laminated stack assembly; 
           [0049]      FIG. 7   c  is an exploded, side view of another embodiment of a notched laminated stack assembly and a cap configured for engagement about an end of the laminated stack assembly; 
           [0050]      FIG. 8   a  illustrates the positioning of resilient nodal mounts on a connecting body without a flange; 
           [0051]      FIG. 8   aa  is an enlarged front view of the nodal area shown in  FIG. 8   a;    
           [0052]      FIG. 8   b  illustrates the positioning of multiple resilient nodal mounts on a connecting body with a flange; 
           [0053]      FIG. 8   bb  is an enlarged front view of the disk shown in  FIG. 8   b;    
           [0054]      FIG. 9   a  is an illustration of tapered cylinder for positioning a resilient mount on a connecting body; and 
           [0055]      FIG. 9   b  is a transverse, cross-sectional view in a first direction of the tapered cylinder of  FIG. 9   a;    
           [0056]      FIG. 9   c  is a transverse, cross-sectional view in a second direction of the tapered cylinder of  FIG. 9   a;    
           [0057]      FIG. 9   d  is a side view of a retaining component with anti-rotation tabs for use with the tapered cylinder of  FIG. 9   a;    
           [0058]      FIG. 9   e  is a transverse, cross-sectional view in a first direction of the retaining component of  FIG. 9   d;    
           [0059]      FIG. 9   f  is a transverse, cross-sectional view in a second direction of the retaining component of  FIG. 9   d ; and 
           [0060]      FIG. 9   g  is an enlarged, side view of the area of detail indicated in  FIG. 9   f.    
       
    
    
     DETAILED DESCRIPTION 
       [0061]    Particular embodiments of the present disclosure are described hereinbelow with reference to the accompanying drawings. In the following description, well known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail. 
         [0062]      FIGS. 1   a  and  1   aa  illustrate a resilient nodal mount  12  and an acoustic transformer, or connecting body  10  having a pair of opposed protrusions  13 . Resilient mounts  12  fit over the protrusions  13  to provide a “soft mount” to the nodal area of the connecting body  10 . The preferred geometry of the protrusions  13  is square because this shape provides the smallest contact area between the protrusions  13  and the resilient mounts  12  and is also the easiest and least expensive to machine. However, other configurations are also contemplated.  FIGS. 1   b  and  1   bb  illustrate the axial mounting of the resilient nodal mounts  12  onto the protrusions  13  of the connecting body  10 . The length L and the diameter D of the resilient nodal mounts  12  are determined by the maximum diameter of the insert grip ( FIGS. 2   a - 2   b ). 
         [0063]      FIGS. 2   a  and  2   b  illustrate the mounting of the connecting body  10  within the grip  20 . More specifically,  FIG. 2   a  illustrates the nests  22  of the grip  20 . As shown in  FIG. 2   b , the nests  22  are configured to capture the soft mount, e.g., the resilient nodal mounts  12  attached to the protrusions  13  of the connecting body  10 . The soft mount assembly is totally contained within the nests  22 . The area between the connecting body  10 , the grip  20 , and the nests  22  allows the flow of coolant fluid across the nodal mount. 
         [0064]      FIG. 3   a  illustrates a bending tool holding fixture  30  for retaining the connecting body  10 . An alignment distance L 2  is defined between a registration point  33  and the beginning of the bending point  32 . The bending arm  31  is shown in the stop position for the completed bend. The contra angle shown in  FIG. 3   b  is achieved by moving the bending arm  31  upward to its vertical stop point (not shown). 
         [0065]    An embodiment of the present disclosure for a low rotational torque insert is illustrated in  FIGS. 4   a  and  4   b , e.g., an insert requiring a rotational torque of between about 0.5 in-oz and about 1.5 in-oz. An elongated sealing gasket  40  having a body defining an internal diameter  47  is provided. The elongated sealing gasket  40  defines a relatively flat outer surface along its length and further includes a pair of circumferential rings defining outer diameters  42  and  41 . The outer diameter  42  of one of the rings of the sealing gasket  40  when mounted in the gland area, e.g., recessed area, of the insert grip  20  is dimensioned to provide an easy insertion into a dental handpiece  45 . This is because the outer diameter  43  is less than the inner diameter  44  of the dental handpiece  45 . The outer diameter  41  is also greater than the outer diameter  42  of the sealing gasket  40 . The low rotational torque of the insert grip  20  is achieved by the combination of the low friction between the circumferential rings defining outer diameters  41  and  42 , and the internal diameter  44  of the dental handpiece  45 . The outer diameters  41  and  42  also provide the required seal for the insert grip  20  when placed in the dental handpiece  45 , during both static and dynamic phases of use. Although the sealing gasket  40  is shown with two circumferential rings, the low rotational torque function is contemplated with a single circumferential ring. It is also contemplated that the function can be achieved by using a sealing gasket  40  without additional circumferential rings, where the machining or molding of a seal gland controls the diameter  43  thereof to have a non-uniform diameter along its length. 
         [0066]    With reference to  FIGS. 5 ,  5   a , and  5   b , the present disclosure further provides for improved durability of a stack assembly (stack of laminations)  50 ,  51 , e.g., Permanickel® laminations, although other laminations are also contemplated. Improved durability and improved electro-mechanical output is achieved by producing lamination shapes with a minimum of two bending angles (stack assembly  51  ( FIG. 5   a )) or three bending angles (stack assembly  50  ( FIG. 5   b )). The typical range for the angles can vary between 100 and 150 degrees. The preferred angles for the double-angle lamination stack assembly  51  are about 118 degrees, while the preferred angles for the triple-angle lamination stack assembly  50  is about 136 degrees, as shown in  FIGS. 5   a  and  5   b , respectively. The actual bending angles are in part determined by the required rigidity of the lamination, the thickness of the lamination, and the maximum final width of the bent lamination. The bend angles allow the stacking of  14  to  16  laminations inside the diameter D 2  of the countersink  19  in connecting body  10 , depending on the thickness of the individual laminations comprising the stack assemblies  50  and  51 . The proximal end diameter D 3  of connecting body  10  is limited by the minimum inside diameter  44  of the dental handpiece  45  (see  FIG. 4   b ). 
         [0067]    A further embodiment of this disclosure provides components  62 ,  60  for housing the stack assembly, e.g., stack assembly  63 , as is illustrated in  FIGS. 6   a ,  6   aa ,  6   b , and  6   bb . The use of a hollow extruded tube  62  or a two-part molded sheath component  60  eliminates the need for special shapes to the laminations. The component  62 ,  60  covers the stack assembly  63  and attaches to the grip  20  ( FIG. 4   b ). In the case of the component  60 , nodal supports  61  are molded at the approximate midpoint of the stack assembly  63 , e.g., the nodal area thereof. This adds additional rigidity to laminations smaller than 0.010 thick. The component material&#39;s molding and welding requirements determine its thickness. Diameter D 4  of sheath component  60  is selected to interface with the diagonal of the stack assembly  63 , such that the outer edges of the stack assembly  63  make contact with the sheath component  60 . Diameter D 5  is dimensioned to assure non-interference fit of tube  62  into inner diameter  44  of handpiece  45  (see  FIG. 4   b ). It is also contemplated that molded sheath  60  have multiple diameters facilitating inclusion of an interface sealing gasket  40  (see  FIG. 4   b ). 
         [0068]    Referring to  FIGS. 7 and 7   a - 7   c,  also provided in accordance with the present disclosure are embodiments configured to eliminate the end brazing on the stack assembly, e.g., stack assembly  50  (or any other suitable stack assembly), without creating high conductivity connections. For example, as shown in  FIG. 7   a , in one embodiment, the distal ends of the laminations  70   a  of the stack assembly are rounded and notches  71  are stamped, typically 0.100 inches, from the rounded end. The laminations  70   a  are placed in a stack and a high temperature heat shrinkable material, e.g., ring  72 , is applied to the notched area to secure the distal end of the stack. In another embodiment, as shown in  FIG. 7   b , the laminations  70   b  are notched but not rounded. The laminations  70   b  are placed in a stack and the distal ends are secured by placement of a cap  73 . Cap  73  is configured with tabs  76  that provide a snap fit to the notches  71 . Cap  73  has slots  77  to facilitate attachment about the stack of laminations  70   b.  A further embodiment, as shown in  FIG. 7   c , includes laminations  70   c  having a relatively small diameter hole  75  extending through the center of the radius of the distal ends of the laminations  70   c.  A component  74 , e.g., a rivet, is inserted into hole  75  and is secured therein in any suitable fashion, e.g., deformation of component  74 , gluing, ultrasonic welding, etc. The rivet may be formed from a low conductivity material. 
         [0069]    A further embodiment of the present disclosure is illustrated in  FIGS. 8   a - 8   bb . The use of resilient mounts as nodal supports requires both axial and rotational stability of the insert grip. In one embodiment, as shown in  FIG. 8   a , connecting body  80  has a nodal area machined with multiple flat surfaces, shown for illustration as a square area  82  ( FIG. 8   aa ). The lead in surfaces to the nodal area  82  are shown as raised areas  83  where the diameter of the raised areas  83  is greater than the diameter of connecting body  80  in area  84 . The raised areas  83  facilitate the positioning of O-ring  81  at the nodal area  82 . In combination, O-ring  81 , nodal area  82 , and raised areas  83  of the resilient nodal mount provide axial and rotational stability. In another embodiment, as shown in  FIG. 8   b , the nodal area on connecting body  85  includes a disk  84  defining a pair of slots (see  FIG. 8   bb ). Disk  84  is sandwiched by O-rings  81 , which in combination comprise a resilient nodal mount and provide axial and rotational stability. 
         [0070]    A further embodiment of a resilient nodal mount provided in accordance with the present disclosure is shown in  FIGS. 9   a - 9   g.  In particular, the mount comprises a tapered cylinder  95  ( FIG. 9   a ) and a retainer  90  ( FIG. 9   b ). This configuration is designed to compress and retain the O-rings  81  ( FIGS. 8   a  and  8   b ). With additional reference to  FIG. 8   b , tapered cylinder  95  is modified by machining a slot on the underside thereof (see  FIGS. 9   b  and  9   c ) to allow tapered cylinder  95  to be inserted over connecting body  85  for retention of O-rings  81 . More specifically, two O-rings  81  are placed on connecting body  85  on both sides of disk  84 . Tapered cylinder  95  is placed between the distal O-ring  81  and the large section of connecting body  85 . Retainer assembly  90  is then placed over the tip end of connecting body  85  and slid into position to capture tapered cylinder  95 . Retainer  90  is moved axially toward tapered cylinder  95  until fingers  94  on retainer  90  engage with the surface of tapered cylinder  95  that defines dimension L 4  on tapered cylinder  95 . Once aligned, retainer  90  is moved axially along connecting body  85  until O-rings  81  are compressed and fingers  94  snap into position within a recess defining dimension L 5  on tapered cylinder  95 . The compression surface for the O-rings  81  on tapered cylinder  95  is defined by the difference between diameters D 6  and D 7  (see  FIG. 9   b ). In cases where the greater concentricity of the assembled parts is necessary, an inverted split washer with an inner diameter of D 7  and an outer diameter of D 6  is placed between tapered cylinder  95  and O-ring  81 . Diameter D 8  provides clearance between connecting body  85  and tapered cylinder  95 . Shoulder  92  on retainer  90  provides clearance between assembly comprising retainer  95  and tapered cylinder  90  when mounted in grip  20  of handpiece  45  (see  FIG. 4   b ). 
         [0071]    In considering assembly of the resilient nodal mount of  FIGS. 9   a - 9   g  onto connecting body  80  ( FIG. 8   a ), tapered cylinder  95  is slid over the small diameter of connecting body  80  with the tapered end with diameter D 6  facing the distal (tip) end of connecting body  80 . An O-ring  81  is placed in the nodal area  82  and the retainer  90  is slid over the tip of the insert, with tabs  91  facing the distal (tip) end of connecting body  80 . Flanges  94  on retainer  90  are aligned to make contact with the tapered edge of tapered cylinder  95 . The retainer  90  and the tapered cylinder  95  are locked together when dimension L 6  on flange  94  snaps into the gap L 5  on tapered cylinder  95 . Dimension L 7  on flange  94  is dimensioned to allow dimension L 6  on flange  94  to spread as it interfaces with tapered cylinder  95 . The dimension L 8  of flange  94  is less than the gap L 5  on tapered cylinder  95  allowing the flange to snap into place. When locked together, the tapered cylinder  95  and retainer  90  compress the O-rings  81 , providing a resilient mount for connecting body  80  when placed into grip  20  of handpiece  45  (see  FIG. 4   b ). Tabs  91  on retainer  90  provide a secure mounting to the grip  20  of handpiece  45  (see  FIG. 4   b ) with axial and rotational stability. Shoulder  92  provides a positive stop for mounting to allow the flow of water past the dimension D 9  on retainer  90 . Dimensions D 8  is based on the diameter of the connecting body that is receiving the resilient mount. Typical dimensions for D 8  are 0.145 to 0.155 inches. The compression surface on tapered cylinder  95  for O-ring  81  is defined by the difference between dimensions D 6  and D 7 . The compression surface  93  on retainer  90  is defined by the difference in dimensions D 10  and D 9 . 
         [0072]    From the foregoing and with reference to the various figure drawings, those skilled in the art will appreciate that certain modifications can be made to the present disclosure without departing from the scope of the same. While several embodiments of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.