Abstract:
A cavity filling apparatus is provided for filling a cavity in a cavity containing member such as a tooth and a restorative dental piece. The cavity filling apparatus includes a filling mass ready space for retaining therein a filling mass, a suction conduit, and an adapter having an adapter channel. In a suction disposition of the cavity filling apparatus, a vacuum is produced in the cavity of the cavity containing member, via the adapter channel, by suction action through the suction conduit. In connection with a filling disposition of the cavity filling apparatus, the filling mass is injected into the cavity, via the adapter channel, from the filling mass ready space. The cavity filling apparatus also includes an assembly for switching the cavity filling apparatus between its suction disposition and its filling disposition.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to an apparatus for filling a cavity of a cavity containing member such as a tooth or a restorative dental piece.  
           [0002]    A cavity filling apparatus for filling teeth cavities has been proposed which comprises a suction conduit communicable with the cavity to thereby apply a vacuum to the cavity. A filling mass which is retained in a filling mass ready space between the suction conduit and a lever positioned above the suction conduit is moved into the cavity upon actuation of the lever.  
           [0003]    This approach has not been comprehensively deployed in practice for the reason that the filling mass ready space realistically must be practically located in the extension of the filling channel which thus necessitates a correspondingly large assembled dimension. Additionally, the actuation lever is still arranged above the filling mass ready space so that only through skill can the dentist effect the desired actuation of the lever. This arrangement also brings with it the complication that there is a projecting lever which acts as an obstacle and which is not well suited for the patient&#39;s mouth and, further, it cannot be completely prevented that the tongue of the patient may unintentionally and involuntarily prematurely actuate the actuation lever.  
           [0004]    It has further been proposed in DE-OS 40 11 568 to fill, in particular, a crown of a tooth via a cavity filling apparatus. This approach is expected to insert the filling material to the deepest possible extent into the root canals. This approach in fact sets the filling inserter under a vacuum so that the filling mass can be inserted in a non-air entraining manner. However, the cavity itself is merely at the pressure of the surroundings so that it is very difficult to avoid entrainment of air in the filling mass during the cavity filling process. The filling inserter, in particular, must be controlled as it is withdrawn from the root canal while, at the same time, the amount of the filling material deposited must be precisely controlled in a manner coordinated with the withdrawal movement of the filling inserter.  
           [0005]    It is therefore not surprising that this just described approach is not comprehensively deployed in practice.  
         SUMMARY OF THE INVENTION  
         [0006]    The present invention provides a cavity filling apparatus which advantageously provides greater ease of use and is secured against disturbances while nonetheless engendering an improved acceptance of such an approach by the patients.  
           [0007]    The cavity filling apparatus of the present invention offers the particular advantage that it engenders improved acceptance by patients because it provides a non-air entraining cavity filling process. In order to make it possible that the adapter of the cavity filling apparatus has only a relatively small height above the bore used for the filling, the cavity filling apparatus of the present invention permits initially also filling the molars on their chewing surface side. Since a special actuation of a projecting lever must be performed, the tendency of the dentist to tilt or angle the adapter in actuating the mechanism which switches between the suction and filling dispositions is strongly reduced, whereby the danger that air is suctioned in and thereby causes air entrainment in the filling material is practically foreclosed.  
           [0008]    The cavity filling apparatus of the present invention permits switching over from the suction disposition to the filling disposition with a natural movement—namely, an increase of the force on the tooth or the restorative dental piece to be filled without necessitating a special hand disposition or an added hand movement of the dentist.  
           [0009]    It is to be understood that while the force exerted on the cavity filling apparatus during the evacuation phase of the filling process as well as the force exerted to effect switching between the suction and filling dispositions is, in a wide range of situations, tailored to the requirements of the task, these forces can also be tailored to the preferences of the individual dentist. It is preferable to provided a modest seating function for the switching mechanism which indicates clearly that the switching has occurred. For example, the force required for switching can be set as triple that of the normal force on the adapter which is applied during the evacuation phase.  
           [0010]    In an advantageous embodiment of the cavity filling apparatus of the present invention, the switch over force is actuated automatically without other intervention by dimensioning the sealing rings of the working body portion which acts against the guide socket of the working body portion. To place in readiness a large actuation force for effecting the switching over between the suction and filling dispositions, it is possible to use O-rings with an increased strength and, to place in readiness a lower actuation force, to use O-rings with a reduced strength. Moreover, the frictional force with respect to the seating force can in any event be finely adjusted through corresponding configuration of the seating groove. It is preferably provided that two seals are disposed axially spaced from one another on a cylindrical working body in the guide socket, each of which respectively seats in a corresponding annular groove in accordance with the position of the working body. The edge steepness of the annular groove determines then the pure switch over force.  
           [0011]    In accordance with a particularly advantageous aspect of the present invention, solely a single adapter channel is provided in the adapter which is deployed as both a suction passage as well as a filling material passage. This solution offers a markedly reduced frequency of disturbances in comparison to solutions having two concentric canals, although also a reduction in the production effort. In accordance with the present invention, the working body itself forms a switchover flank, whereby, in a first disposition of the working body (the suction disposition of the cavity filling apparatus), a filling inlet of the filling mass ready space is closed off by the working body or, more precisely, by the switchover flank. In contrast, in a second disposition of the working body (the filling disposition of the cavity filling apparatus), a working opening of the adapter channel can be oriented toward the filling inlet in the most obstacle-free manner so that the filling mass can enter the adapter channel in a blockage-free manner and pass from there into the cavity.  
           [0012]    In accordance with the present invention, it is particularly advantageous if the viscosity of the filling mass is exploited for the purpose of keeping the filling mass free from entrained air. Although as a basic premise the filling of the filling mass ready space would be possible by pressing movement of an injector head, in accordance with the present invention, an integral suctioning or drawing of the filling mass is preferable. In this connection, a small yet nonetheless defined gap is provided in the working area between the working body and the guide socket. Air is drawn into this gap from a suction coupling which is immediately adjacent the filling mass ready space and extends perpendicularly therefrom and the drawn in air then travels out of the adapter channel and into the cavity of the tooth or the restorative dental piece. At the same time, air is drawn through the gap between the switch over angle and the filling inlet so that a vacuum is produced in the filling mass ready space. Since the cavity forms an enclosed space with the adapter channel when the channel is firmly communicated therewith, further suctioning via the suction conduit produces a vacuum in the filling mass ready space and this vacuum acts to draw in a filling mass which has been pre-positioned in an injector until the filling mass borders on the filling inlet. As soon as this occurs, the vacuum in the adapter channel increases and the vacuum increases as well in the suction conduit so that it is possible to detect via a pressure detector when the adapter is ready for a switchover from the suction disposition to the filling disposition.  
           [0013]    In accordance with the present invention, it is particularly advantageous if the vacuum produced in the cavity acts to draw the adapter thereagainst. The seal between the adapter and the cavity is for this reason not critical, whereby it is advantageous if the angle of an outer cone on the adapter is selected such that the adapter maintains itself in communication with the tooth or the restorative dental piece after it has initially been disposed thereon.  
           [0014]    In an especially advantageous embodiment of the cavity filling apparatus of the present invention, a static mixer is provided through which pass the two components which comprise the filling mass. In accordance with the present invention, this occurs via the heretofore described suction force so that the components are at the same time free of entrained air. The static mixer can be configured as a spiral threaded component which is received in a cylinder having an inner diameter sized in correspondence with the outer diameter of the spiral. An intensive mixing of the two components with one another occurs due to the suctioning of the filling mass for the reason that the filling mass, which tends to follow the spiral passage, is at the same time subject to shearing during its passage due to the fact that suitable measures such as a rotation preventing securement member are provided to ensure that the injector connecting component, in which the spiral threaded component is disposed, does not rotate.  
           [0015]    The cavity filling apparatus of the present invention lends itself to an especially cost favorable manufacturing thereof. The guide socket which collectively comprises the filling mass ready space and the adapter body can also be manufactured as a single unit. It is also possible to releasably dispose the adapter body in the guide socket so that a cleaning can be facilitated.  
           [0016]    In a further particularly advantageous embodiment of the invention, it is provided that an additional coupling is also located adjacent the suction coupling on the guide socket for the purpose of measuring the respective vacuum.  
           [0017]    Additional advantages, details, and features are set forth in the following description in connection with the figures of the drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]    [0018]FIG. 1 is an exploded perspective view of one embodiment of the cavity filling apparatus of the present invention;  
         [0019]    [0019]FIG. 2 is a perspective view of the one embodiment of the cavity filling apparatus shown in FIG. 1 prior to its assembled together condition;  
         [0020]    [0020]FIG. 3 is another perspective view of the one embodiment of the cavity filling apparatus shown in FIG. 1 in its assembled together condition;  
         [0021]    [0021]FIG. 4 is a perspective view of the one embodiment of the cavity filling apparatus shown in FIGS.  1 - 3 ;  
         [0022]    [0022]FIG. 5 is an enlarged perspective view of portions of the one embodiment of the cavity filling apparatus shown in FIGS.  1 - 3 ;  
         [0023]    [0023]FIG. 6 is an enlarged cross-sectional view of portions of the one embodiment of the cavity filling apparatus shown in FIG. 1;  
         [0024]    [0024]FIG. 7 is an enlarged sectional view of the working unit portion of the one embodiment of the cavity filling apparatus shown in FIG. 1 and showing the working unit portion in the suction disposition of the cavity filling apparatus; and  
         [0025]    [0025]FIG. 8 is an enlarged sectional view of the working unit portion of the one embodiment of the cavity filling apparatus shown in FIG. 1 and showing the working unit portion in the filling disposition of the cavity filling apparatus. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0026]    As seen in FIG. 1, the cavity filling apparatus  10  of the present invention includes a working unit portion  12 , an injector connecting component  14 , a static mixer  16 , an injector cylinder component  18  and a double injector plunger  20 . When deployed, these components are in the assembled together disposition shown in FIG. 3 and these components are shown in the exploded unassembled disposition in FIG. 1 for the sake of clarity of understanding.  
         [0027]    The working unit portion  12  comprises a working body  22 , a guide socket  24  in which the working body  22  is slidably received, and a filling space  26 .  
         [0028]    The working body  22  further includes an actuation cap  28  which retains the working body in the guide socket  24 . The working body  22  forms together with the actuation cap  28  an adapter  30  and includes on its lower end an adapter cone  32 . The adapter cone  32  is configured for insertion into a bore in a tooth or restorative dental piece which can itself be conically shaped with a cone angle corresponding to that of the adapter cone  32 .  
         [0029]    The guide socket  24  is configured of minimal length and is integrally built as a single unit with the filling space  26 , whereby the filling space  26  is formed substantially as a pipe which extends outwardly from the guide socket.  
         [0030]    A suction coupling  34 , whose function will be described in more detail below, and a pressure measurement coupling  36  are disposed below the filling space  26 .  
         [0031]    As can be readily seen in FIG. 2, the injector connecting component  14  can be partially inserted into the pipe  38  which forms the filling mass ready space  26 . A rotation preventing securement member  40 , provided on the outer periphery of the injector connecting component, engages corresponding tabs  42  of the injector cylinder component  18 . A static mixer  16 , which is in the shape of a spiral threaded component, is disposed in the injector connecting component  14  before the assembling together of the injector connecting component. The injector cylinder component  18  includes two cylinders, shown in FIG. 1, which are each filled with a material component to be mixed and injected. The filling mass in the filling mass ready space  26  is formed by the intensive mixing of the two material components with one another.  
         [0032]    The working unit portion  12  is shown in an enlarged view in FIGS. 4 and 5. FIG. 4 shows the suction position of the adapter  30  in the guide socket  24  and FIG. 5 shows the filling position of the adapter in the guide socket. In the suction position of the adapter  30 , the actuation cap  28  is in a flat contact position on the top side of the guide socket  24 . In this position, the working body  22  is projected clearly downwardly.  
         [0033]    In contrast, the working body  22  extends outwardly above the guide socket  24  in the filling position while solely the adapter cone  32  projects downwardly.  
         [0034]    In connection with the transition between the suction position shown in FIG. 4 and the filling position shown in FIG. 5, it is sufficient if the dentist exerts from above a total downward force on the pipe  38  of the filling mass ready space  26 . A transformer device  35  is configured for this purpose.  
         [0035]    As can be seen in particular in FIG. 5, the pressure measurement coupling  36  and the suction coupling  34  extend in differing vertical planes as well as at an offset from one another. These couplings can be disposed at the smallest possible assembled height and, to ensure that the two couplings  34  and  36  each extend sideways adjacent the pipe  38 , the two couplings can be conducted parallel to the pipe  38  out of the mouth of the patient.  
         [0036]    Conduits which are not illustrated form a connection to a supply unit.  
         [0037]    The pipe  38  includes—as can be seen in particular in FIG. 5—a rotation preventing securement member  40  which receives and supports therefrom the injector connection body  14 . It is to be understood that a coupling without free play and, as desired, corresponding sealing members can be provided.  
         [0038]    A cavity filling apparatus of the present invention is shown in FIG. 6 in a disposition in which the adapter  30  is disposed for administering a filling dose. It can be seen that the static mixer  16  practically completely fills a cylindrical inner volume  43  of the injector connection body  14 . The static mixer  16  is so configured that it rests on the inner volume  43  under a resilient bias yet can be removed as required for, for example, the purpose of cleaning.  
         [0039]    [0039]FIG. 7 shows the individual elements of the adapter  30  as they are assembled into assembled condition in the guide socket  24 . The working body  22  of the adapter  30  is substantially cylindrical but nonetheless includes a not insubstantial annular groove  44  disposed slightly above the middle of the working body. The working body  22  further includes a first seal  46 , a second seal  48 , and a third seal  50 , each of which is configured as an O-ring seal. The seals  46 ,  48 , and  50  seal off the guide socket  24 . The rotational position of the working body  22  within the guide socket  24  is set by a rotation preventing securement member (not illustrated). The working body  22  further includes a working opening  52  which is communicated with the annular groove  44  and extends toward the filling mass ready space  26  into communication with an adapter channel  54 . The adapter channel extends through the entirety of the working body  22  as well as the adapter cone  32 .  
         [0040]    The filling mass ready space  26  terminates in a filling coupling  56  which extends toward the working body  22 . As shown in FIG. 7, the filling coupling  56  in the suction position of the working body  22  is closed off by the transformation edge  58  of the working body while, as shown in FIG. 8, the filling coupling  56  in the filling position is open to the adapter channel  54 .  
         [0041]    A gap  60  of a predetermined width extends between the working body  22  and the guide socket  24 . The suction coupling  62  is communicated with the gap  60  such that a vacuum exists in the gap and from there into other regions. The vacuum extends into the annular groove  44  and via the groove into the adapter channel  54 . Since the seal  50  in the suction position shown in FIG. 7 is above the filling coupling  56 , the vacuum extends as well into the filling coupling  56  and from there into the filling mass ready space  26 . This leads to the condition that a filling mass, which is not shown, is drawn in by the vacuum condition to be disposed at the transformation edge  58 . The viscosity of the filling mass is sufficiently large that it cannot enter into the gap  60  so long as the working body  22  remains in the suction position.  
         [0042]    The suction position as shown in FIG. 7 is maintained for a predetermined period such as, for example, five minutes or more, to permit the evacuation of the cavity or hollowed out space in the tooth or the restorative dental piece. In this connection, the cavity and the adapter channel  54  are initially evacuated, whereby a remainder pressure of from 10 to 15 mbar remains automatically without further intervention. The vacuum propagates through the filling mass ready space  26  and effects a drawing in of the filling mass from the injector through the static mixer  16  into the filling mass ready space  26  until this space is filled. As soon as the filling mass ready space  26  is filled, no further air remains to be evacuated, whereby a suction occurrence is precluded. The dentist then presses from above on the pipe  38  so that the filling position shown in FIG. 8 is achieved. The switch over permits the filling mass to be injected from the filling mass ready space  26  through the adapter channel  54  into the cavity in the tooth. Thereafter, as a stronger vacuum ensues, the filling space is filled in a complete and air entrapment-free manner.  
         [0043]    An inventive seating apparatus  64  is provided to make available a fixed transformation or switch over position. The seating apparatus  64  includes an annular groove  66  located in the interior of the guide socket  24  which cooperates with the first seal  46  and the second seal  48 . In the first position, which is the suction position as shown in FIG. 7, the first seal  46  is seated in the annular groove  66 . In this position, the first seal  46  is freely positioned and the vacuum existing in the gap  60  can be measured, whereby the measurement is conducted via the pressure measurement coupling  36 .  
         [0044]    For the transformation or switch over of the adapter  30  into the second position, which is the filling position, shown in FIG. 8, initially the first seal  46  is displaced out of its seated position in the annular groove and, upon further displacing movement, the second seal  48  seats in the annular groove  66 .  
         [0045]    The spacing between the seals  46  and  48  is selected such that the spacing is greater than the width of the annular groove  66 , whereby a constant vacuum sealing is ensured in the interior of the working unit portion  12 .  
         [0046]    The actuation cap  28  is—as shown in FIGS. 7 and 8—threaded into a corresponding threaded receiving portion of the working body  22 . To permit cleaning of the working body  22  and the working unit portion  12 , the actuation cap  28  is released from its threaded retention so that the working body  22  can be withdrawn downwardly out of the guide socket  24 . The actuation cap  28  is ball shaped for ease of reconfiguring the cavity filling apparatus from the filling position shown in FIG. 8 into the suction position shown in FIG. 7 in preparation for the filling thereof for the next tooth filling operation.  
         [0047]    The specification incorporates by reference the disclosure of German priority document 100 64 005 2.  
         [0048]    The present invention is, of course, in no way restricted to the specific disclosure of the specification and drawings, but also encompasses any modifications within the scope of the appended claims.