Abstract:
Dental device acting as a variable-height mouth opener, a saliva ejector and an oral dam including a casing having a shape reproducing the shape of the dental arches and able to maintain the patient&#39;s mouth open once inserted into it in contact with the dental arches, and a saliva discharge opening communicating with a tube for removing the saliva by suction applied to the other end of the tube. The size of the device casing in the mastication direction can be varied from a minimum to a maximum, for example, by pivotally mounting a projecting element to the casing.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a dental device acting simultaneously as a mouth opener, an oral dam and a saliva ejector. 
     BACKGROUND OF THE INVENTION 
     A dental instrument of this type is already known from Italian Patent Application No. RC94U 000011, which has the same inventor as the present application. This instrument comprises: 
     a casing having a shape reproducing the shape of the dental arches and able to maintain the patient&#39;s mouth open once inserted into it in contact with the dental arches; and 
     a saliva discharge opening communicating with a tube for removing the saliva by suction applied to the other end of the tube. 
     The aforedescribed instrument is conveniently provided with means for coupling the instrument to the patient&#39;s teeth in order to maintain the instrument in position relative to the patient&#39;s mouth. 
     Using such an instrument, it has been found that although being very useful in achieving sufficient opening of the patient&#39;s mouth, its casing is too bulky in the mastication direction, so that it is uncomfortable to insert into the patient&#39;s mouth. 
     Moreover, because of its size in mastication direction, the known dental instrument does not leave sufficient space free for the dentist to carry out the operations required within the patient&#39;s mouth with ease. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a device of the aforesaid type which avoids the above-mentioned drawbacks of the instrument disclosed in Italian Patent Application No. RC94U 000011, i.e., it does not have a casing which is bulky in the mastication direction and therefore it is not uncomfortable to insert into the patient&#39;s mouth, and leaves sufficient space free for the dentist to operate in the patient&#39;s mouth. 
     Another object of the present invention is to provide a new and improved dental device acting as a variable-height mouth opener, a saliva ejector and an oral dam. 
     In order to attain these objects and others, a dental device in accordance with the invention comprises means for varying the size of the device casing in the mastication direction from a minimum to a maximum. In this manner, the device casing can be easily inserted into the patient&#39;s mouth when in its minimum size state, after which, the casing can be made to assume its maximum size in the mastication direction. 
     Further, to provide for sufficient space for the dentist to operate in the patient&#39;s mouth, the device has a casing of reduced size in the mastication direction and from the casing, once inserted into the patient&#39;s mouth, an element having transverse dimensions substantially smaller than the transverse dimensions of the casing itself is able to project towards the palate until it makes contact with the palate. This projecting element is lockable in its projecting position. In this manner, a considerable free space occupied only by the projecting element remains between the casing and palate. 
     Conveniently, the free end of the projecting element is shaped to adapt to the shape of the palate region with which it is intended to make contact. 
     Preferably, the casing is hollow and open at the insertion end for the patient&#39;s tongue so that this can enter the casing. 
     In one particular embodiment, the dental device comprises a casing having a shape reproducing the shape of dental arches and adapted to maintain the patient&#39;s mouth open once inserted into the patient&#39;s mouth and in contact with the dental arches, the casing including a saliva discharge opening adapted to receive a tube for removing saliva from the patient&#39;s mouth by suction applied to an end of the tube, and engaging means coupled to the casing for selectively engaging a palate of the patient&#39;s mouth and thereby secure the casing in the patient&#39;s mouth. The engaging means comprise a projecting element having a first end and a second end and is movable between a first position in which the first end is situated in the casing and the second end is exterior of the casing and a second position in which the first end is situated exterior of the casing and the second end is situated in the casing. When the first end is exterior of the casing, the casing has a larger size in the mastication direction then when the first end is situated in the casing. The projecting element may be lockable in the second position, e.g., by locking means, and may also be sickle-shaped and lie substantially in a vertical plane. In the latter case, a horizontal pin pivotally mounts the projecting element to the casing at an intermediate point and the casing comprises a slit in a front face through which the first end of the projecting element projects when in the second position. thus, the locking means may entail the slit comprising two notches and a wedge adapted to be inserted into one of the notches to lock the projecting element in a position of maximum projection of the first end. 
    
    
     The invention will be described in detail with reference to some preferred embodiments of the invention illustrated in the figures in the accompanying drawing. However, the invention is not confined to the illustrated embodiments alone. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Additional objects of the invention will be apparent from the following description of the preferred embodiment thereof taken in conjunction with the accompanying non-limiting drawings, in which: 
     FIG. 1 is a front perspective view of the device in accordance with the invention in its condition of maximum size in the mastication direction; 
     FIG. 2 is a rear perspective view of the device in accordance with the invention; 
     FIG. 3 is a perspective right side view of the device in accordance with the invention when in its state of minimum size in the mastication direction 
     FIG. 3 a  is a perspective view of the sickle element as seen in FIG. 3; and 
     FIG. 4 is a perspective left side view of the device in accordance with the invention when in its maximum size state. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1-4 wherein like reference numerals refer to the same or similar elements, a dental device in accordance with the invention is designated generally as  10  and comprises a casing  12  of non-traumatic material, such as a plastic material suitable for the use for which it is intended, or a suitable rubber, which must however be fairly rigid. The casing  12  has an outer shape which roughly reproduces the shape of the dental arches and, in this specific case, is hollow and open both to the rear and downwards, with the advantage that the internal cavity of the casing  12  can accommodate the patient&#39;s tongue. 
     As can be seen in particular from FIGS. 1 and 2, the casing  12  is not symmetrical but rather includes an external concavity  14  in its right side (see FIG.  1 ). This is because the relative device has been designed for the case in which the patient&#39;s left dental semi-arch is to be operated upon, the concavity  14  hence providing greater operating space in the relative region. Likewise, the device of the invention can be given a shape similar to that of the illustrated casing  12 , if the patient&#39;s right dental semi-arch is to be operated upon. 
     Returning to the embodiment shown in FIGS. 1-4, it can be seen in particular from FIG. 3 that in the right side of the casing  12  there is provided a through hole  16  enabling one end of a saliva ejector tube  18  to be inserted into the casing  12 , its other end being connected to a usual vacuum source. As can be seen from FIG. 2, the tube  18  is retained by a sleeve  20  fixed to the inner wall of the casing  12 . 
     A projecting element, such as a connecting rod or sickle element  24 , is rotatably fixed to the casing  12  by a horizontal pin  22  at an intermediate point, to thereby be able to rotate in a vertical plane. As can be seen from FIGS. 3 and 4, as well as lying in a vertical plane, the sickle element  24  has a first end  28  projecting from a vertical slit  30  (FIGS. 1 and 4) provided in the front of the casing  12 . The other end of the sickle element  24  can project from a rearwardly open aperture  32  (FIGS. 1 and 2) provided in the top of the casing  12 . On the end of the sickle element  24 , there is fixed a counteracting element or cap  34  of the same material as the casing  12 . The sickle element  24  can assume two different angular positions, namely a first position (visible in FIG. 3) in which the first end  28  of the sickle  24  projects considerably from the casing  12  via the slit  30 , whereas the second end of the sickle  24 , including the cap  34 , does not project from the casing  12 , and a second position in which the first end  28  of the sickle  24  does not project from the casing  12  (however in FIG. 1 this is not shown distinctly), whereas the second end on which the cap  34  is fixed projects considerably from it. 
     In correspondence with the vertical slit  30 , the casing  12  comprises on its front face two special notches, of which one of these, indicated by  36 , can be seen in FIG. 3. A wedge  38  can be inserted into these notches to lock the sickle element  24  in its most projecting position. Instead of the notches  36  and wedge  38 , other means can be provided to lock the second end of the sickle element  24  in its projecting position. 
     It should also be noted that besides comprising a right or left concavity  14 , the described dental device can be constructed in various sizes to enable each patient to use the most suitable device. 
     A brief description will now be given of the method of using the described device  10 . The device  10  is positioned in the patient&#39;s mouth such that the convex front surface of the casing  12  (that visible in FIG. 1) faces the inner surface of the patient&#39;s incisors, whereas its upper face (that from which the cap  34  can project upwards), also convex, faces the patient&#39;s palate. The roughly U-shaped lower edge of the casing  12  hence makes contact with the floor of the patient&#39;s mouth. As shown seen in FIGS. 1,  2  and  3 , this edge comprises in its front an incisure to prevent trauma to the caruncle of the tongue. Before inserting the casing  12  into the patient&#39;s mouth, it must be checked that the sickle  24  lies in the angular position shown in FIG. 3, so that insertion can take place without any difficulty., i.e., the device has the minimum transverse dimension to facilitate insertion into the patient&#39;s mouth. 
     As already stated, as the casing  12  has a concavity or depression  14  on the right (with reference to FIG.  1 ), it is suitable for operating on the patient&#39;s left dental semi-arch. If it is required to operate on the right dental semi-arch a casing is used which is mirror-image to the casing  12  (i.e., in which the concavity is on the left, again with reference to FIG.  1 ). 
     After positioning the casing  12  in the patient&#39;s mouth, the first end  28  of the sickle  24  is pressed with one finger so that this end totally enters the casing  12 , i.e., is situated in the casing  12 . This makes the cap  34  project upwards out of the casing  12 , to lie as in FIGS. 1,  2  and  4 . At this point, the wedge  38  is inserted into the notches  36  to lock the sickle  24  in position. Consequently, the patient can no longer close his mouth. Upon removal of the wedge  38 , the cap  34  can be made to re-enter the casing  12 , enabling the casing  12  to be easily extracted from the patient&#39;s mouth. 
     As will be easily apparent the dental device of the invention facilitates the dentist&#39;s work in that: 
     it allows the field of operation to be totally isolated thereby preventing interference by the tongue and ingress of saliva, the device acting as a barrier interposed between the teeth and the mouth cavity; 
     it maintains the patient&#39;s mouth open, hence acting as a mouth opener; 
     it enables saliva to be drawn off to provide a dry field of operation, hence acting as a saliva ejector; 
     it provides improved vision of the field of operation; and 
     it can be quickly put in place. 
     Above, some preferred embodiments of the invention have been described, and it is obvious to a person skilled in the art that numerous modifications can be made to these embodiments within the scope of the inventive idea defined in the accompanying patent claims. As such, the examples provided above are not meant to be exclusive. Many other variations of the present invention would be obvious to those skilled in the art, and are contemplated to be within the scope of the appended claims.