Abstract:
Devices and methods for the application of materials to an interior space of a tooth, such as the extirpated pulp chamber and/or root canals of the tooth subsequent to root canal surgery. The device has one or more syringe-like pistons and associated chambers for drawing a vacuum within an extirpated pulp chamber and applying cleansing, sealing, and/or filler materials into the tooth under continued vacuum pressure to ensure complete and thorough application.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention pertains to endodontic devices and methods, and more particularly to devices for and methods for cleaning and filling the pulp chamber of an endodontically extirpated root canal.  
         BACKGROUND OF THE INVENTION  
         [0002]    Root canal therapy is a well-known procedure whereby the crown of a diseased tooth is opened to permit the canal to be cleaned and filled. In a normal procedure, pupal tissues are first removed from the canal, the canal is then cleaned and a sealer is applied, and finally the canal is filled with a filling material, generally gutta percha, synthetic gutta percha, or a composite filler.  
           [0003]    A critical aspect of root canal therapy is the removal of all bacterial matter from the pupal chamber as well as the complete filling of the extirpated pupal chamber to prevent subsequent damage to the tooth or infection of the patient. Traditional methods of applying cleaning solutions and filler to extirpated root canals by injection or compaction are prone to the formation of air pockets within the canal, and thus complete cleansing and filling cannot be assured. Furthermore, the filling of canals by compaction methods is a time consuming and labor intensive process. To overcome these drawbacks, several devices have been proposed in which vacuum pressure is applied to an extirpated canal to eliminate air pockets and thus facilitate the complete distribution of cleansing and filling materials. Typical of such devices are those found in U.S. Pat. No. 5,046,950 to Favonio, No. 5,171,146 to Guerci, and No. 5,295,828 to Grosrey. While these devices have addressed the problems associated with the formation of air pockets, they generally employ pumps, valves, and other mechanical or electrical components, making them quite complex and therefore expensive to manufacture and maintain.  
           [0004]    Accordingly, there is a need for an apparatus and methods for applying cleansers, sealants, and filler materials to extirpated root canals under vacuum pressure, but without the complexity and expense of devices previously proposed for such purposes.  
         BRIEF SUMMARY OF THE INVENTION  
         [0005]    The present invention provides simplified devices and methods for the delivery of one or more fluids to an interior tooth space, such as extirpated root canals, under vacuum pressure in order to facilitate the complete and thorough treatment of the entire canal. Such fluids may, for example, be cleaning or rinsing fluids, digestive/sterilizing fluids, or filler materials, as well as other types of fluids. The invention provides various advantages over previous methods and apparatus used for cleansing and filling root canals under vacuum pressure. For example, the present invention eliminates or at least reduces the need for motorized pumps, valves, or other mechanical and electrical features. The invention thus provides a more compact and less complex device, which in turn is less expensive to purchase, use and maintain compared to previously available devices.  
           [0006]    In a general aspect of the invention a syringe-like device has one or more chambers. In the two chamber embodiments, one chamber creates vacuum pressure in an extirpated pulp chamber and root canals and one dispenses a fluid material, such as a cleansing solution or filler material, into the evacuated chamber and canals. Each chamber has a dedicated conduit or passage to an applicator tip that can be placed in the opening of the pulp chamber so that the canal can be evacuated and filled with a desired substance. Each chamber is fitted with a plunger that has a piston for expelling air or other fluids, such as cleansing solution or filler material, as the plungers are advanced into their respective chambers. In the single chamber embodiment, the vacuum and dispensing functions are integrated into one chamber with one or more pistons separating respective dispensing and vacuum portions of the chamber.  
           [0007]    The applicator tip of each embodiment is constructed to seal against an opening in the tooth to allow for adequate evacuation of the pulp chamber and root canals. The sealing is preferably provided by an o-ring type seal fixed to the end of the tip/nozzle, but may be substituted or augmented by a resilient tube or any other suitable sealing material capable of providing a substantially air-tight seal against a tooth. As one additional alternative, the seal may be formed from a small amount of filler or sealing material placed around the opening to the root canal. In a preferred embodiment of the invention, the chambers, the conduits leading to the tip, and the applicator tip itself are integrated into a single body.  
           [0008]    In another aspect of the invention the device includes a plurality of chambers for dispensing multiple fluid materials into an evacuated pulp chamber and root canals. Accordingly, the device includes a plurality of plungers as described above, one for each chamber of the device. In this aspect of the invention, a plurality of cleansing solutions or filler materials may be applied to a root canal cavity either sequentially or at the same time.  
           [0009]    In another aspect of the invention, an embodiment having a plurality of dispensing chambers includes structure for mixing the plurality of dispensed materials while they are being expelled from their respective chambers. The mixing structure may be a section of the applicator tip where the plurality of materials may freely mix, or the structure may include baffles to provide more thorough mixing of the dispensed materials. The mixing structure may be disposed within the tip of the apparatus or may be attached to the end of the tip. Other mixing apparatus may be used as well.  
           [0010]    In yet another aspect of the invention, the plungers are connected together so that they can be uniformly advanced into their respective chambers in a single actuation of the plurality of plungers. In a preferred embodiment, the plunger rods associated with the dispensing chamber(s) are shorter in length or otherwise configured relative to the plunger rod for the vacuum chamber so that the creation of a vacuum within an extirpated tooth precedes the expulsion of cleansing solution or filler material into the tooth.  
           [0011]    In another aspect of the invention, a method for cleansing, sealing, or filling the extirpated pulp chamber of a tooth includes positioning the device of the present invention to engage an opening of a tooth, advancing a first plunger to create a vacuum in an interior space of the tooth, and advancing the same plunger or a second plunger to dispense materials from the device into the interior space of the tooth.  
           [0012]    Accordingly, a general objective of the present invention to provide a simple, compact and inexpensive device and a method of use for the effective cleansing and filling of extirpated root canals under vacuum pressure. These and other advantages, objectives and features of the invention will become more readily apparent to those of ordinary skill upon review of the following detailed description of an illustrative embodiment of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    [0013]FIG. 1 is cross sectional view of one embodiment of the apparatus of the present invention generally taken along a longitudinal axis of the apparatus and a tooth;  
         [0014]    [0014]FIG. 1A is a cross sectional view similar to FIG. 1, but illustrating the apparatus in use to evacuate the pulp chamber of the tooth;  
         [0015]    [0015]FIG. 1B is a cross sectional view similar to FIG. 1A, but illustrating the further step of filling the pulp chamber with filler material;  
         [0016]    [0016]FIG. 2 is a cross sectional view similar to FIG. 1, but illustrating a second embodiment of the present invention;  
         [0017]    [0017]FIG. 2A is a cross sectional view similar to FIG. 2, but showing an initial actuation of the plungers to create vacuum pressure within the pulp chamber of a tooth;  
         [0018]    [0018]FIG. 2B is a cross sectional view similar to FIG. 2A, but showing further actuation of the plungers to dispense filler material into the pulp chamber; and  
         [0019]    [0019]FIG. 3 is a cross sectional view similar to FIGS. 1 and 2, but illustrating a third alternative embodiment of the present invention having a plurality of dispensing chambers and plungers.  
         [0020]    [0020]FIG. 4 is a cross sectional view similar to FIGS. 1, 2 and  3 , but illustrating a fourth alternative embodiment of the present invention that eliminates the use of a separate vacuum space.  
         [0021]    [0021]FIG. 4A is a cross sectional view similar to FIG. 4, but illustrating the apparatus in use to evacuate the pulp chamber of the tooth.  
         [0022]    [0022]FIG. 4B is a cross sectional view similar to FIG. 4A, but illustrating the further step of filling the pulp chamber with filler material. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0023]    Referring to FIG. 1, an apparatus  10  for filling extirpated root canals has a body  12  that includes a vacuum chamber  14  and a dispensing chamber  16  integrally formed with the body  10 . Dispensing chamber  16  contains conventional filler material  17 , such as one or more one-part fillers, composite filler materials, resin, gutta percha, or other filler materials as necessary or desired for a particular application. As additional non-limiting examples, cleaning or sterilizing solutions, such as water, sodium hypochlorite, EDTA or others, may be delivered with a device of this invention. Body  12  further includes a vacuum conduit  18  and a dispensing conduit  20 , connected to vacuum chamber  14  and dispensing chamber  16  respectively. Conduits  18  and  20  join together to form an applicator tip  22  that is shaped preferably to fit within an opening  24  formed in a tooth  26 . However, it need not actually extend into opening  24  as long as an adequate seal is formed. In the preferred embodiment, a seal  27 , schematically illustrated as an O-ring type seal, is affixed around the outside of tip  22  to seal pulp chamber  28  and root canals  29  of the tooth  26  in a manner allowing a vacuum or negative pressure condition to exist therein. It will be appreciated that, while an O-ring is illustrated for clarity, other conventional dental sealing materials may be applied against tip  22  and tooth  26  to maintain an adequately sealed condition during use of device  10 .  
         [0024]    Plungers  30  and  32  are comprised of plunger rods  34  and  36 , pistons  38  and  40 , and thumb pads  42  and  44 . Pistons  38  and  40  are respectively disposed within vacuum chamber  14  and dispensing chamber  16  and are constructed to slidably seal against the interior walls of their respective chambers  14 ,  16 . Plunger rods  34  and  36  extend outside of the body  12  from within chambers  14  and  16  and terminate in thumb pads  42  and  44  such that pistons  38  and  40  may be independently urged along the vacuum and dispensing chambers  14  and  16  when pressure is applied to the thumb pads  42  and  44 . Body  12  also includes a flange or other finger grip  46  that can be gripped by an operator to make it easier to apply pressure to thumb pads  42  and  44 .  
         [0025]    To operate apparatus  10 , as illustrated in the position shown in FIG. 1, the operator first grasps apparatus  10  with flange  46  and thumb pad  42  between their fingers and thumb. Thumb pad  42  and plunger  30  are then depressed to develop a partial vacuum within pulp chamber  28  and root canals  29  as shown in FIG. 1A. As vacuum piston  38  is moved through vacuum chamber  14 , the effective volume on the plunger rod side of the piston  38  is increased, creating a suction in vacuum conduit  18 . This, in turn, creates partial vacuum inside sealed pulp chamber  28  of tooth  26  prior to expulsion of filler material  17  from dispensing chamber  16 . A breather hole or vent  54  of vacuum chamber  14  allows air to escape from the chamber  14  as piston  38  is advanced. On the opposite side of piston  38 , vacuum pressure in the vacuum chamber  14  is maintained by a seal  56  through which plunger  30  protrudes. After vacuum has been drawn in pulp chamber  28 , plunger  32  is depressed using thumb pad  44 . Piston  40  thereby expels filler material  17  through conduit  20  and into pulp chamber  28 . After pulp chamber  28  is filled, apparatus  10  is removed by detaching tip  22  and the outer end of opening  24  then may be sealed or closed in a conventional manner.  
         [0026]    [0026]FIGS. 2, 2A and  2 B illustrate an alternative apparatus  10 ′ according to the invention, wherein plungers  30  and  32 ′ are connected via a common thumb pad  48  so that both plungers may be advanced in unison. In FIGS. 2, 2A and  2 B, like numerals represent common elements of structure with the embodiment of FIGS. 1, 1A and  1 B. Reference numerals with prime (′) marks represent structure that is somewhat changed as compared to the first embodiment, as will be apparent from the illustrations. Plunger rod  36 ′ is detached from piston  40  and is shorter than plunger rod  34  disposed in the vacuum chamber  14  so that a gap  50  is created between rod  36 ′ and piston  40  in dispensing chamber  16 , thereby causing a delay between the actuation of pistons  38  and  40  when pressure is applied to thumb pad  48  to uniformly advance plungers  30  and  32 ′.  
         [0027]    To fill an extirpated pulp chamber  28  and root canal  29  of tooth  26  apparatus  10 ′ is positioned proximate tooth  26  such that the tip  22  substantially fills an opening  24  to the pulp chamber  28 . Tip  22  again includes an appropriate seal  27  located at its distal end for engaging tooth  26  and creating a substantially air-tight seal between the ends of the conduits  18  and  20  and the pulp chamber  28 . With the tip  22  in place, an operator applies pressure to thumb pad  48 , using flange  46  for leverage, thereby uniformly advancing plunger rods  30  and  32 ′. Due to gap  50 , vacuum plunger rod  34  urges vacuum piston  38  through vacuum chamber  14  before dispensing plunger rod  36 ′ engages dispensing piston  40 . As vacuum piston  38  is moved through vacuum chamber  14 , the effective volume on the plunger rod side of the piston  40  is increased, creating a suction in vacuum conduit  18 , which in turn creates a partial vacuum inside sealed pulp chamber  28  of tooth  26  prior to expulsion of filler material  17  from dispensing chamber  16 . A breather hole  54  of vacuum chamber  14  allows air to escape from the chamber  14  as piston  38  is advanced. On the opposite side of piston  38 , vacuum pressure in the vacuum chamber  14  is maintained by a seal  56  through which plunger  30  protrudes. Those of ordinary skill will, after reviewing this illustrative embodiment, realize that other configurations of the plunger rods, chambers and/or pistons, as well as the positioning of the filler material or other fluid material(s) may be changed while still resulting in the desired delay.  
         [0028]    As shown in FIGS. 2A and 2B, when dispensing plunger rod  36 ′ contacts dispensing piston  40  after covering the distance created by gap  50 , piston  40  is urged through the dispensing chamber  16  to expel the filler material  17  from chamber  16  through dispensing conduit  20  and into pulp chamber  28 , while vacuum plunger  30  continues to advance and, therefore, maintain vacuum pressure in the pulp chamber  28 . FIG. 2B depicts the filling of pulp chamber  28  and root canals  29  with the contents  17  of the dispensing chamber  16  under continued vacuum pressure caused by the advance of vacuum piston  38  through vacuum chamber  14 . It will be appreciated that the continued application of vacuum pressure to pulp chamber  28  and root canals  29  as these areas are being filled serves to eliminate air pockets therein and to promote complete filling of the root canals  29  and pump chamber  28  with material  17 . Various materials  17  may be used depending on the purpose of the procedure. For example, to cleanse or apply sealant to an extirpated pulp chamber, the same process described above or below is followed, but dispensing chamber  16  is filled with cleaning solution or sealant as appropriate.  
         [0029]    [0029]FIG. 3 depicts another alternative embodiment of the present invention. Again, in this embodiment, elements with like reference numerals as compared with the first two embodiments represent like structure, while elements with double prime (″) marks are corresponding elements that have been somewhat modified as will be apparent. Detailed description of like elements is contained above and, therefore, these descriptions are not repeated. In this third embodiment, apparatus  10 ″ includes multiple dispensing chambers  58  and  60  with corresponding plungers  62  and  64 , dispensing pistons  63  and  65 , and dispensing conduits  66  and  68  with tip  22 ″ for dispensing several different materials from the multiple dispensing chambers  58  and  60  at the same time. A mixing baffle  70  is attached to the tip  22 ″ of apparatus  10 ″, proximate the exit of the plurality of dispensing conduits  66  and  68  to mix the dispensed materials as they enter the pulp chamber  28 . Apparatus  10 ″ operates as described above with regard to FIGS. 2, 2A and  2 B, with the exception that it is capable of dispensing multiple types of materials  17 ,  17 ″ from the dispensing chambers and mixing those materials  17 ,  17 ″ prior to their discharge into pulp chamber  28  of tooth  26 . The operation of this embodiment is as described for the second embodiment.  
         [0030]    [0030]FIGS. 4, 4A and  4 B illustrate another alternative embodiment of the current invention. Again, as in previous embodiments, elements with like reference numerals as compared to the first three embodiments represent like structure, while elements with the triple prime (′″) marks are corresponding elements that have been somewhat modified as will be apparent. Detailed description of like elements is contained above and, therefore, these descriptions will not be repeated. In this embodiment, apparatus  10 ′″ contains a single dispensing chamber  16  with pistons  82  and  86 , separated by a space  83 . Pistons  82  and  86  are designed to be slidably sealed against the interior walls of chamber  16  while piston  82  is also attached to or, at least, capable of being moved by plunger  80 . Plunger rod  81  contains a venting port  84  that is oriented coaxially along the long axis of the plunger rod  81 . This port  84  communicates with the space  83  at one end of the plunger  80  via a hole  82   a  in the center of piston  82 . Venting port  84  vents to the outside of apparatus  10 ′″ through vent hole  87  located just beneath thumb pad  85  and along the outer edge of plunger rod  81 . Note that vacuum chamber  14  has been entirely disposed of in this embodiment and has been replaced with an extended vacuum conduit  18 ′″.  
         [0031]    In order to facilitate the filling of a pulp chamber  28  and root canals  29 , apparatus  10 ′″ is positioned relative to tooth  26  such that tip  22  and seal  27  engage the tooth opening  24  and an air tight seal is formed.  
         [0032]    While tip  22  is engaged, thumb pad  85  is depressed using flange  46  for leverage. This initially advances only piston  82 . As piston  82  is advanced, air from space  83  is forced out of venting port  84  and expelled to the atmosphere via vent hole  87  (FIG. 4A). As space  83  is evacuated, a pre-vacuum is created in a space  89  located on the plunger side of piston  82  and in communication with the vacuum conduit  18 ′″. The effect of this pre-vacuum is to draw the air from the pulp chamber  28  and the root canals  29  through the extended vacuum conduit  18 ′″ so as to evacuate the tooth prior to the movement of the filler material  17  (see FIG. 4A). Space  83  essentially acts to delay the movement of piston  86  (and therefore filler material  17 ) until space  83  is completely evacuated and the pulp chamber  28  and root canals  29  are at least substantially evacuated.  
         [0033]    Once space  83  is evacuated, piston  82  abuts piston  86  (FIG. 4B). Continued pressure on thumb pad  85  simultaneously advances pistons  82  and  86 . The vacuum in the pulp chamber  28  and root canals  29  is thereby further increased as air is drawn into the emptied dispensing chamber  16  on the plunger side of advancing pistons  82  and  86 . This action causes the expulsion of filler material  17  from the dispensing chamber  16  into the evacuated pulp chamber  28  and root canals  29  until chamber  28  and canals  29  are completely filled.  
         [0034]    It will be appreciated that pistons  82 ,  86  may be replaced by a single piston which simultaneously dispenses filler material  17 , or another fluid material in accordance with the invention, while evacuating the interior of tooth  26 . In other words, there would be no pre-vacuum provided as in the embodiment shown in FIGS. 4, 4A and  4 B. In addition, the embodiments utilizing one or more pistons in the same dispensing chamber may also be adapted to multiple dispensing chambers, for example, each having a different fluid material. In such an embodiment, a vacuum conduit would communicate with the back side or plunger side of each dispensing chamber.  
         [0035]    While the present invention has been illustrated by a description of preferred embodiments and while the embodiments have been described in considerable detail, it is not the intention of the Applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages, modifications and adaptations of this invention will become apparent to those skilled in the art upon reviewing this disclosure. The various features of each embodiment may be combined with one or more features of other embodiments, or other features as desired in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method as shown and described. The invention itself should only be defined by the appended claims, wherein I claim: