Abstract:
Apparatus for manipulating a dental device comprises first and second gripping elements rotatably coupled to one another for movement between a gripping configuration in which a first gripping surface of the first gripping element is positioned adjacent a second gripping surface of the second gripping element to grip a dental device there between and a release configuration in which the first and second gripping surfaces are spaced from one another, wherein each of the first and second gripping surfaces includes a device receiving recess shaped to accommodate a gripping portion of a device to be gripped by the apparatus and a locking mechanism for locking the first and second gripping elements in the gripping configuration. The apparatus may further include a seating surface for applying a seating force to a bearing surface of the dental device.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention is applicable to the field of devices used in dentistry.  
         BACKGROUND INFORMATION  
         [0002]    Many branches of dentistry require the use of various small devices for restoring a tooth to normal form and function. For example in the field of operative dentistry, the restoration of teeth often requires the insertion of posts, screws and/or pins into a tooth to provide support and/or retention of the restorative material. Often the teeth being treated are non-vital—i.e., the nerve of the tooth has been removed from the root canal. These teeth are often structurally weak and may require strengthening to withstand the forces applied by the jaw. An endontically treated tooth is frequently treated by the insertion of a prefabricated post that is cemented into the root canal while providing for retention of a core. The core provides a base upon which the final crown will be placed to restore the clinical crown of the tooth. In this type of procedure, pins, screws and other small dental devices are inserted into the tooth to act as fasteners and as strengthening elements.  
           [0003]    However, serious harm to the patient is possible if such a device is accidentally dropped into the patient&#39;s mouth. Swallowing such a device may cause injury to the patient, and in any case greatly complicates the procedure. Due to this potential for injury, extra care is required in performing such procedures which are consequently more time consuming and which require increased skill.  
         SUMMARY OF THE INVENTION  
         [0004]    In one aspect, the present invention is directed to an apparatus for manipulating a dental device comprising first and second gripping elements rotatably coupled to one another for movement between a gripping configuration in which a first gripping surface of the first gripping element is positioned adjacent a second gripping surface of the second gripping element to grip a dental device there between and a release configuration in which the first and second gripping surfaces are spaced from one another and wherein each of the first and second gripping surfaces includes a device receiving recess shaped to accommodate a gripping portion of a device to be gripped by the apparatus. In addition, the apparatus includes a locking mechanism for locking the first and second gripping elements in the gripping configuration.  
           [0005]    In another aspect, the invention is directed to a carrier for a dental device, comprising a grasping portion adapted to releasably retain a gripping head of the dental device and to control angular movement of a body of the dental device, shaped surfaces of the grasping portion complementing a shape of the gripping head, a seating portion adapted to apply a seating force to a bearing surface of the dental device, and a handle to manipulate the carrier.  
           [0006]    In yet another aspect, the invention is directed to a method of placing a dental device in a tooth. The method includes retaining a gripping head of the dental device in a gripping portion of a carrier, the gripping portion conforming to a shape of the gripping head, rotating a body of the dental device to a desired angular orientation, locking the gripping portion to prevent loss of the dental device, and manipulating the carrier to place the dental device in a desired location in the tooth. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    [0007]FIG. 1 is a side elevation view of a conventional post carrier, with an enlarged side elevation view of a prefabricated post;  
         [0008]    [0008]FIG. 2 is an exploded perspective view of a prefabricated post seated in the root canal of a tooth;  
         [0009]    [0009]FIG. 3 a  is a side elevation view of the dental device carrier according to an embodiment of the present invention shown in the open configuration;  
         [0010]    [0010]FIG. 3 b  is a side elevation view of the dental device of FIG. 3 a  in the locked configuration with a prefabricated post gripped thereby; and  
         [0011]    [0011]FIG. 4 is an enlarged perspective detail view of the gripping section of an arm of the dental device carrier shown in FIG. 3. 
     
    
     DETAILED DESCRIPTION  
       [0012]    The present invention may be further understood with reference to the following description and the appended drawings, wherein like elements are referred to with the same reference numerals. According to embodiments of the present invention, a method and device is provided to safely transport and position posts, screws, pins and other dental devices into a patient&#39;s teeth, and positively seat those dental devices in the patient&#39;s teeth. The restoration of vital and non-vital teeth are examples of procedures to which the invention is applicable.  
         [0013]    The pins, posts and screws described herein are generally referred to as dental devices, and may include small objects that are used in dental procedures. Some of these dental devices may be used to strengthen the tooth by providing anchorage or retention of the restorative materials used to build up the clinical crown to form and function. During such procedures, the need to strengthen and restore a tooth to normal function is a primary goal of the dental practitioner. As described above, the placement of small posts and other dental devices into the remaining sound tooth structure is a difficult and taxing procedure which may be dangerous to patients if these small devices are not handled properly.  
         [0014]    The following description of methods and devices according to embodiments of the present invention focuses on the installation of a post in a tooth following root canal therapy (endontia). It will be apparent to those skilled in the art that the present invention is not limited to this procedure, and that the foregoing discussion is exemplary in nature.  
         [0015]    The exemplary post  10  has a generally elongated shape, and is made of a strong, non allergenic material such as a titanium alloy. A strong metal alloy is necessary due to the large forces that are applied to the post during mastication. Post  10  includes a body  12  and a gripping head  14  which is used to hold post  10  in the carrier at a desired angle to to enter the root canal of the tooth being treated. Body  12  fits in the root canal of the tooth as shown in FIG. 2. Those skilled in the art will understand that, although the carrier  40  is described in conjunction with a post  10  having a gripping head  14 , the carrier  40  is equally effective for pins, posts and screws with no head or which are gripped by their substantially cylindrical stems.  
         [0016]    According to exemplary embodiments of the present invention, a dental device carrier and manipulator is used in dental restorative procedures to positively control the orientation of the dental device, such as post  10 , as it is inserted in the tooth. The carrier is also used to safely transport the dental device to the tooth with a reduced risk of dropping it in the mouth, and of possible ingestion by the patient. FIG. 3 shows one embodiment of the carrier  40 , shown in the open configuration (a) and in the locked configuration (b), with a dental device which in this case is a post  10 . The exemplary carrier  40  operates in a scissor-like manner, such that grasping portion  42  can retain post  10  when in the locked configuration, and can release it when in the open configuration. A handle  44  is provided for the user to control the opening and closing of the grasping portion  42 . A locking mechanism  46  may be provided to lock the carrier  40  in the locked configuration. For example, locking mechanism  46  may be a ratchet mechanism with multiple locking positions, or may be any other appropriate locking mechanism known in the art.  
         [0017]    An exemplary grasping portion  42  of the carrier  40  is shown in greater detail in FIG. 4. Grasping portion  42  comprises two opposing gripping elements  50  that move relative to one another so that a distance between first operative surfaces  60  varies. In the preferred embodiment, the gripping elements  50  are formed as a pair of jaws pivotally connected so that, as they are rotated relative to one another, ends of the jaws move toward and away from one another. In this embodiment, the distance varies in response to the operation of handle  44  by the dentist. First operative surfaces  60  are each formed facing each other on one side of each gripping element  50 , and are shaped so that they can act in unison to retain the gripping head  14  of post  10 . When carrier  40  is in the open configuration, first operative surfaces  60  are separated by a distance greater than a dimension of gripping head  14 , and do not retain it. As the distance is reduced by closing carrier  40  towards the locked configuration, first operative surfaces  60  close in on gripping head  14 , and retain it there between. In this embodiment, body  12  of post  10  extends beyond grasping portion  42  at a selected angle, so that it may be inserted within tooth  30  as shown in FIG. 2.  
         [0018]    In the exemplary embodiment, first operative surfaces  60  are shaped to conform to the shape of gripping head  14  of post  10 . In this case, an indentation  52  is formed on each of first operative surfaces  60  with each of the indentations  52  being formed substantially as a portion of a sphere so that, when they are placed adjacent to one another, they substantially match that of the gripping head  14 . A ball joint and socket-like connection is thus temporarily formed between carrier  40  and post  10 . When a small force is used to bring together gripping elements  50 , the body  12  may be moved angularly about gripping head  14  with relative ease. If the force is increased, the joint tightens so that gripping head  14  is retained in place and rotation within the spherical cavity is resisted, so that post  10  remains in the selected angular orientation until the dentist applies a force to the device. That is, when the carrier  40  is locked onto the gripping head  14 , the post  10  is substantially frictionally prevented from rotating under its own weight. However, the ball and socket nature of this coupling preferably allows the dentist to rotate the gripping head  14  to any desired orientation by applying a force to the body  12  of the post  10 .  
         [0019]    In one embodiment, a stepped portion  54  may be included towards tip  58  of each of the gripping elements  50 . Stepped portion  54  forms a gap between gripping elements  50  when they are brought together in the locked configuration. The gap has a dimension approximating the dimension of body  12 , so that post  10  can be moved angularly across stepped portion  54  while being retained within carrier  40 . The extent and shape of stepped portion  54  may be selected to limit angular movement of body  12  as desired. It will be apparent to those of skill in the art that other shapes of first operative surface  60  may be selected, without departing from the scope of the invention. Depending on the shape of gripping head  14 , indentation  52  may not be hemispherical, but instead may be elliptical, parabolic, faceted, etc.  
         [0020]    Carrier  40  also includes a seating portion, which in this example includes a second operative surface  62  formed facing forward at the tip  58  of grasping portion  42 . The second operative surface  62  may be used, for example, to seat any post  10  which has previously been seated in a tooth  30  and may be particularly useful to seat a post  10  which has a shank which must seat on the face of the tooth  30 . As described above in regard to the indentations  52 , for handling a post  10  including a substantially spherical gripping head  14 , the second operative surface  62  may preferably be formed substantially as a portion of a sphere to receive a top of the gripping head  14  so that pressure applied to the carrier  40  will be transmitted via the surface  62  to the post  10  to seat it. In this example, second operative surface  62  is divided in two halves, each being formed at the tip  58  of a corresponding one of the gripping elements  50 . The second operative surface  62  thus includes two indentations  56 , one on each of gripping elements  50 , which when brought together cooperate to form a substantially hemispherical concave surface or a concave surface which forms less than half a sphere. It will be apparent to those of skill in the art that the second operative surface  62  does not have to be formed by two parts, and does not have to be located at the tip  58  of gripping elements  50 . The second operative surface  62  may be used, for example, to apply a force to the post  10  to maintain the post  10  in a fully seated position until the luting material has fully set.  
         [0021]    Any location on carrier  40  may be used, as long as the dentist using the device may apply the second operative surface  62  to the gripping head  14  to apply a seating force to the post  10 . It will also be apparent that additional shapes other than a partially indentations  56  may be used depending on the shape of the bearing surface formed on the post  10 .  
         [0022]    A procedure for utilizing the system according to the present invention in restoring an endontically treated tooth is described with reference to FIGS. 2, 3 and  4 . The post carrier  40  is used to transport the post  10  to the tooth  30  and to facilitate its insertion into the post hole during try-in. Proper and rapid seating of the post  10  can thus be ensured by using the post carrier  40 . The gripping head  14  of the post  10  is manually placed between the gripping elements  50  of the carrier  40 , so that the spherical gripping head  14  is retained in the cavity formed by the indentations  52 . After body  12  has been maneuvered to a desired angular direction, the carrier  40  is tightened to the locked configuration to prevent further movement of the post  10  relative to the carrier  40 . The post  10  may then be safely transported to the tooth  30  being treated, and can be manipulated to insert it into a post hole formed in the root canal  32 . Since the carrier  40  is maintains a positive lock on the post  10 , the dentist is able to orient the body  12  to easily enter the post hole formed in the root canal  32  at the desired angle simply by manipulating the prefabricated post  10  held in the closed haws of the carrier  40  and the overall safety of the operation is enhanced.  
         [0023]    After the post  10  has been inserted in the tooth  30 , the carrier  40  is unlocked and moved to the open configuration, to release gripping head  14 . Second operative surface  62  is then used to press down on gripping head  14 , to ensure post  10  is properly seated in root canal  32 . This step promotes a strong bond and correct positioning of post  10  within the tooth  30 .  
         [0024]    [0024]FIG. 2 and the foregoing discussion refer in particular to restoration of anterior and bicuspid teeth. When it is necessary to restore molar teeth, especially non-vital molar teeth, the preferred technique is to place more than one post in each tooth, to increase the coronal strength of the core material used in the restoration. Molar teeth have multiple root canals, and to maximize the strength of the restoration the posts should not be placed parallel to one another. For upper molars, the upper molar palatal root is generally the principal root canal in which the post is placed. A second post that is narrower and shorter may be placed in the mesio-buccal or disto-buccal root canals. For lower molars, the principal post is generally placed in the molar distal canal, while smaller supplementary posts are placed in a second mesio-buccal or mesio-lingual canal. The preparation of the root canal to receive the post is generally conventional, as described above.  
         [0025]    Those skilled in the art will understand that, when placing multiple posts  10  in a multi-rooted tooth, it may be beneficial to utilize more than one carrier  40  to facilitate pick-up and placement of the posts  10  in an efficient manner. This allows the dentist to seat the posts  10  prior to set of the cementing medium used in the procedure.  
         [0026]    The present invention has been described with reference to specific embodiments associated with the insertion of dental posts in teeth during restorative procedures. However, other embodiments may be devised that are applicable to other dental devices and procedures, without departing from the scope of the invention. Accordingly, various modifications and changes may be made to the described embodiments without departing from the broadest spirit and scope of the present invention as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative rather than restrictive sense.