PATENT ABSTRACT
Disclosed is a dental instrument for cutting soft tissue. The dental instrument for cutting soft tissue according to the present invention includes: a main body having an inlet portion for inserting soft tissue to be cut into the main body; a cutter blade arranged in the main body such that at least a part of the cutter blade is exposed outwardly through the inlet portion; and a lid for covering the upper portion of the main body. The cutter blade includes a first cutter blade having a first cut depth, and a second cutter blade arranged in the vicinity of the first cutter blade, and which has a second cut depth shallower than the first cut depth. The dental instrument of the present invention makes it possible to cut the soft tissue in the deep part of a mouth in an easy and simple process, thereby improving the convenience of soft tissue implantation.

PATENT DESCRIPTION
TECHNICAL FIELD 
       [0001]    The inventive concept relates to a dental instrument, and more particularly, to a dental instrument for cutting soft tissue in the oral cavity to provide soft tissue used for a soft tissue transplantation surgery. 
       BACKGROUND ART 
       [0002]    In general, a biomaterial may be divided into hard tissue and soft tissue. Bones or teeth are examples of the hard tissue. Skin, blood vessels, cartilages, or ligaments are examples of the soft tissue. The hard tissue has an elastic coefficient and a tensile strength that are higher than those of the soft tissue. 
         [0003]    The soft tissue as a biomaterial has been used in the field of dental treatment. In particular, soft tissue transplantation surgeries have been widely used as a method for rebuilding or treating damaged soft tissues during a dental surgery such as implant surgery. 
         [0004]    In case of an implant surgery that is recently in the limelight, gums around an implant need to be healthy so that a tooth implant may be used for a long time. This is the same principle that is used for a case in which a flag driven into sands. The flag does not fall when a large amount of sand exists around the flag. That is, even when an alveolar bone firmly holds the root of a tooth, the tooth may sway when the gum surrounding the tooth is insufficient. Also, exposed nerves may cause pain and it is not aesthetic. In this case, a soft tissue transplantation surgery is needed. 
         [0005]    To transplant soft tissues to an area where the thickness of a gum is thin or the gum is lost, soft tissue to be transplanted needs to be primarily obtained. To this end, soft tissues in an amount needed for transplantation are cut off from other normal area in the oral cavity. Typically, soft tissues in the palate of the oral cavity are used because the flesh of the palate is relatively thicker than that of other places. 
         [0006]    Dental instruments for cutting soft tissue are used to cut the soft tissue off from the oral cavity to provide soft tissue used for a soft tissue transplantation surgery. 
         [0007]    A conventional dental instrument for cutting soft tissue may include a main body equipped with a blade, a cover covering the upper portion of the main body, and a handle coupled to the main body and held by an operator. The blade is coupled to the main body by being separated therefrom to have a predetermined cutting depth. Also, the main body and the cover may be formed in a single body. 
         [0008]    In the meantime, soft tissue cut including the outer surface of a particular portion in the oral cavity may be used as the soft tissue to be transplanted in a portion having a thin thickness or in a place where gum is lost. However, it is advantageous to use soft tissue arranged at a predetermined depth under the outer surface of the particular portion in the oral cavity because of a high transplantation success rate. 
         [0009]    Since the conventional dental instrument for cutting soft tissue is equipped with a single blade having a predetermined cutting depth, to cut soft tissue arranged at a predetermined depth under the outer surface of the particular portion in the oral cavity, soft tissue is primarily cut by a predetermined depth under the outer surface and secondarily soft tissue by a desired thickness is cut off from the portion where the outer surface is removed. 
         [0010]    In addition, the cutting depth of a blade installed at a dental instrument for cutting soft tissue used for the first cutting process is different from that of a blade installed at a dental instrument for cutting soft tissue used for the second cutting process. Thus, two or more dental instruments for cutting soft tissue are needed for cutting soft tissue. Furthermore, when a single dental instrument for cutting soft tissue is in use, it is inconvenient to replace the blade for each process. 
       DETAILED DESCRIPTION OF THE INVENTION 
     Technical Problem 
       [0011]    The inventive concept provides a dental instrument for cutting soft tissue which may easily and simply cut soft tissue arranged at a predetermined depth under the outer surface in the oral cavity so that a soft tissue transplantation surgery may be facilitated. 
       Advantageous Effects 
       [0012]    According to the present inventive concept, since the dental instrument for cutting soft tissue employs a dual blade structure of the first and second blades having different cutting depths, the soft tissue arranged at a predetermined depth under the outer surface in the oral cavity may be easily and simply cut so that a soft tissue transplantation surgery may be facilitated. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  illustrates the structure of a plasma processing apparatus according to an embodiment of the present invention; 
           [0014]      FIG. 2  is a perspective view of a gate value of  FIG. 1 ; 
           [0015]      FIG. 3  is a partially cut perspective view of the gate valve taken along line III-III of  FIG. 2 ; 
           [0016]      FIG. 4  is a perspective view of a cylinder of  FIG. 2  during a normal operation; 
           [0017]      FIG. 5  is a perspective view of a cylinder of  FIG. 2  during a maintenance and repair operation; and 
           [0018]      FIG. 6  is a perspective view of a locking pin of  FIG. 4   
       
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
       [0019]    According to an aspect of the inventive concept, there is provided a dental instrument for cutting soft tissue, which includes a main body in which an inlet hole through which cut soft tissue is input is formed, a blade provided at the main body, at least a portion of the blade being exposed to the outside through the inlet hole, and a cover covering an upper portion of the main body, wherein the blade includes a first blade having a first cutting depth, and a second blade provided adjacent to the first blade and having a second cutting depth smaller than the first cutting depth. 
         [0020]    The second blade may be arranged in front of the first blade with respect to a cutting direction. 
         [0021]    Each of the first and second blades may include a cutting portion where a blade surface is formed and exposed to the outside through the inlet hole, and a pair of wing portions bent and extending from both ends of the cutting portion and supported by the main body in the main body. 
         [0022]    To fix the position of the blade in the main body, a position fixing hole may be formed in each of the wing portions and a position fixing protrusion inserted in the position fixing hole may be formed in the main body. 
         [0023]    A position fixing recess engaged with the position fixing protrusion may be formed in the cover. 
         [0024]    An exhaust hole through which soft tissue input through the inlet hole is exhausted may be formed in the cover. 
         [0025]    A guide wall extending toward the inlet hole may be provided at a position adjacent to the exhaust hole to guide the soft tissue input through the inlet hole to the exhaust hole. 
         [0026]    The guide wall may be inclined with respect to a center line of the exhaust hole. 
         [0027]    A blade installation portion recessively formed in an area including the inlet hole may be provided at the main body, and a protruding portion protruding from an area including the exhaust hole to be engaged with the blade installation portion may be provided at the cover. 
         [0028]    The first and second blades may be either separately or integrally formed. 
         [0029]    The blade may be manufactured separately from the main body and coupled to the main body. 
         [0030]    The blade may be formed of metal and the main body is formed of plastic, and the blade may be integrally formed at the main body by injection molding. 
       MODE FOR CARRYING OUT THE INVENTION 
       [0031]    The attached drawings for illustrating embodiments of the inventive concept are referred to in order to gain a sufficient understanding of the inventive concept and the merits thereof. 
         [0032]    Hereinafter, the inventive concept will be described in detail by explaining embodiments of the inventive concept with reference to the attached drawings. Like reference numerals in the drawings denote like elements. 
         [0033]      FIG. 1  is a perspective view of a dental instrument for cutting soft tissue according to an exemplary embodiment of the present inventive concept.  FIG. 2  is an exploded perspective view of the dental instrument for cutting soft tissue of  FIG. 1 .  FIG. 3  is a rear perspective view of the cover of  FIG. 2 .  FIG. 4  is an enlarged perspective view of the blade of  FIG. 2 .  FIG. 5  is a side view illustrating a portion of the dental instrument for cutting soft tissue of  FIG. 1 .  FIG. 6  is a plan view of the dental instrument for cutting soft tissue of  FIG. 1 . 
         [0034]    Referring to  FIGS. 1 and 2 , a dental instrument  100  for cutting soft tissue (hereinafter, referred to as the dental instrument) according to an exemplary embodiment of the present inventive concept is a dental instrument for cutting soft tissue in the oral cavity, mainly, the soft tissue of the palate, to provide soft tissue used for a soft tissue transplantation surgery. The dental instrument  100  may include a main body  110  having blades  140  and  150  for cutting soft tissue in the oral cavity, a cover  120  covering the upper portion of the main body  110 , and a handle  130  extending long from the main body  110  to be held by an operator. 
         [0035]    In the present exemplary embodiment, the main body  110 , the cover  120 , and the handle  130  are formed of plastic that may be injection molded in consideration of manufacturing convenience and lightness. However, the material of the main body  110 , the cover  120 , and the handle  130  of the dental instrument according to the present inventive concept is not limited to plastic and other material such as metal may be used therefor. 
         [0036]    Referring to  FIGS. 1-6 , an inlet hole  112  for guiding soft tissue cut by the blades  140  and  150  is formed in the main body  110  of the dental instrument  100 . A blade installation portion  114  in which the blades  140  and  150  are installed is recessively formed in an area including the inlet hole  112 . The blades  140  and  150  are installed at the blade installation portion  114  such that the center portions of the blades  140  and  150  may be exposed to the outside through the inlet hole  112 . 
         [0037]    The cover  120  of the dental instrument  100  is coupled to the main body  110  to cover the upper portion of the main body  110 . An exhaust hole  122  through which soft tissue input through the inlet hole  112  of the main body  110  is exhausted is formed in the cover  120 . In the present exemplary embodiment, the cover  120  is coupled to the main body  110  in a forced fit. To this end, a hook groove  126  formed at the leading end of the cover  120  is engaged with a hook step  116  formed at the leading end of the main body  110 . Also, a pair of insertion holes  128  in which a pair of insertion protrusions  118  formed at the rear end of the main body  110  are inserted are provided at the rear end of the cover  120 . An adhesive may be coated between the lower surface of the cover  120  and the upper surface of the main body  110  for a more firm coupling therebetween. 
         [0038]    However, in the present inventive concept, the coupling method between the cover  120  and the main body  110  is not limited to the above description and a variety of methods may be adopted instead. For example, the cover  120  may be hinge coupled to the main body  110  to open or close the upper portion of the main body  110 . In this case, the exhaust hole  122  through which soft tissue input through the inlet hole  112  of the main body  110  is exhausted may be omitted. 
         [0039]    That is, when the cover  120  is coupled to the main body  110  to open and close the upper portion of the main body  110 , a space defined by the main body  110  and the cover  120  may accommodate the cut soft tissue. Accordingly, even when the exhaust hole  122  is not formed in the cover  120 , the cut soft tissue may be taken out by opening the cover  120 . In addition, the cover  120  and the main body  110  may be integrally manufactured by injection molding. 
         [0040]    A protruding portion  124  protrudes from an area including the exhaust hole  122  to be engaged with the blade installation portion  114  of the main body  110 , as illustrated in  FIGS. 2 and 3 . The protruding portion  124  of the cover  120  fixes the blades  140  and  150  by pressing both ends of the blades  140  and  150  installed at the blade installation portion  114 . Accordingly, the blades  140  and  150  may be stably fixed in the main body  110  so that movements particularly in upward and downward directions may be prevented. 
         [0041]    Also, a guide wall  129  is provided at the lower surface of the cover  120  by extending from a position adjacent to the leading end of the exhaust hole  122  toward the inlet hole  112  of the main body  110 , as illustrated in  FIGS. 3 and 6 . The guide wall  129  guides the soft tissue input through the inlet hole  112 . The guide wall  129  is inclined with respect to the center line of the exhaust hole  122 , as illustrated in  FIG. 3 . This is to facilitate the delivery of the cut soft tissue input through the inlet hole  112  to the exhaust hole  122 . Also, the guide wall  129  extends toward a position adjacent to the blades  140  and  150  exposed to the outside through the inlet hole  112 . This is to prevent the input of the soft tissue cut by the blades  140  and  150  through the inlet hole  112  and the escape of the soft tissue between the blades  140  and  150  and the lower surface of the main body  110 . 
         [0042]    Referring to  FIGS. 1 and 2 , the handle  130  of the dental instrument  100  is a portion held by an operator during the cutting of the soft tissue in the oral cavity. The handle  130  is formed of the same plastic material as that used for the main body  110  and integrally formed with the main body  110 . In the present inventive concept, however, the handle  130  may be coupled to the main body  110  to be detachable in a screw coupling method, unlike the present exemplary embodiment. 
         [0043]    Referring to  FIGS. 2-5 , the blades  140  and  150  installed at the main body  110  have a dual blade structure including the first blade  140  and the second blade  150  arranged adjacent to the first blade  140 . Both of the first and second blades  140  and  150  are formed of metal. The second blade  150  is arranged in front of the first blade  140  with respect to a cutting direction along an arrow of  FIG. 5 . That is, with respect to the leading end of the main body  110 , the second blade  150  is arranged behind the first blade  140 . 
         [0044]    The first and second blades  140  and  150  respectively include cutting portions  142  and  152  exposed to the outside through the inlet hole  112  and having blade surfaces  141  and  151 , and a pair of wing portions  144  and  154  bent and extending from both ends of the butting portions  142  and  152  and supported by the blade installation portion  114  in the main body  110 . 
         [0045]    The cutting portions  142  and  152  are portions where the blade surfaces  141  and  151  are formed with respect to the cutting direction and have a shape of “␣” to be exposed to the outside through the inlet hole  112 . Also, the wing portions  144  and  154  are coupled to the main body  110  and horizontally bent and extending from both ends of the cutting portions  142  and  152  that are vertical to the lower surface of the main body  110 . The wing portions  144  and  154  are placed and supported on the blade installation portion  114  by being inserted in the main body  110  via the inlet hole  112 . The wing portions  144  and  154  placed and supported on the blade installation portion  114  are pressed and fixed by the protruding portion  124  of the cover  120  as described above. The blade surfaces  141  and  151  are inclined at a predetermined angle with respect to the cutting direction, as illustrated in  FIG. 3 . This is to improve the cutting performance of the blade surfaces  141  and  151 . 
         [0046]    The first and second blades  140  and  150  having the above-described structure have a dual blade structure having different cutting depths H 1  and H 2 . That is, the cutting portion  142  of the first blade  140  is exposed to the outside through the inlet hole  112  so that the first blade  140  may have the first cutting depth H 1 . The cutting portion  152  of the second blade  150  is exposed to the outside through the inlet hole  112  so that the second blade  150  may have the second cutting depth H 2 . The cutting depth denotes a distance from the lower surface of the main body  110  to the blade surface  141  or  151 , which determines the thickness of the soft tissue cut during the soft tissue cutting. 
         [0047]    As described above, the soft tissue transplantation surgery in the dental field denotes a surgery of cutting a desired amount of soft tissue off from a particular portion, mainly, the palate, in the oral cavity, and transplant the cut soft tissue in a gum, when the thickness of a gum around a portion where an implant is placed is thin or the gum is insufficient. Although the cut soft tissue including the outer surface of the particular portion in the oral cavity may be used as soft tissue to be transplanted in the gum that is thin or lost, soft tissue arranged at a predetermined depth under the outer surface of the particular portion in the oral cavity is used because of its high transplantation success rate. 
         [0048]    However, since a conventional dental instrument for cutting soft tissue is equipped with a single blade having a predetermined cutting depth, to cut soft tissue arranged at a predetermined depth under the outer surface of the particular portion in the oral cavity, soft tissue at a predetermined depth under the outer surface is primarily cut and secondly soft tissue of a desired thickness is cut off from a portion where the outer surface is removed. These processes are inconvenient. 
         [0049]    Also, since the cutting depths of a blade installed at a dental instrument used for the first cutting process and a blade installed at a dental instrument used for the second cutting process are different from each other, two or more dental instruments are needed for cutting the soft tissues in the soft tissue cutting processes. Furthermore, when a single dental instrument is used to cut soft tissue, it is inconvenient to replace the blade for each process. 
         [0050]    To solve the above inconvenience generated when the conventional dental instrument is in use, the dental instrument  100  according to the present exemplary embodiment has a dual blade structure of the first blade  140  and the second blade  150  having the different cutting depths H 1  and H 2  so that the soft tissue transplantation surgery may be facilitated. 
         [0051]    That is, in the dental instrument  100  according to the present exemplary embodiment, since the second blade  150  having the cutting depth H 2  smaller than the cutting depth H 1  of the first blade  140  is arranged in front of the first blade  140  with respect to the cutting direction, the soft tissue arranged at a predetermined depth under the outer surface of the particular portion in the oral cavity may be cut in a single cutting process. 
         [0052]    In detail, when an operator cuts soft tissue off from the particular portion in the oral cavity using the dental instrument  100  according to the present exemplary embodiment, the soft tissue is cut by the first blade  140  to a thickness corresponding to the second cutting depth H 2  off from the outer surface of the particular portion. The upper and lower surfaces of the soft tissue arranged at a predetermined depth under the outer surface of the particular portion are respectively cut by the second blade  150  and the first blade  140  so that the cut soft tissue is input between the first and second blades  140  and  150 . 
         [0053]    Accordingly, when soft tissue is cut off from the particular portion in the oral cavity by using the dental instrument  100  according to the present exemplary embodiment, the soft tissue arranged at a predetermined depth under the outer surface of the particular portion in the oral cavity may be cut by using a dental instrument equipped with blades having different cutting depths or by not replacing the blade. 
         [0054]    The first and second blades  140  and  150  may be installed separately, but close to each other, at the blade installation portion  114  of the main body  110 . Alternatively, the first and second blades  140  and  150  may be integrally formed and installed at the blade installation portion  114  of the main body  110 . The first and second blades  140  and  150  may be manufactured by performing cutting and bending processes to a blade having a long plate shape. In terms of manufacturing convenience, the first and second blades  140  and  150  may be separately formed. In terms of assembly convenience and stability, the first and second blades  140  and  150  may be integrally formed. Also, when the first and second blades  140  and  150  are separately formed, the first and second blades  140  and  150  are installed at the main body  110  by being in contact with each other or slightly separated from each other. 
         [0055]    Also, as described above, the positions of the first and second blades  140  and  150  may be fixed in the main body  110  as the blade installation portion  114  recessively formed in the main body  110  and the protruding portion  124  protruding from the cover  120  are pressed to contact each other with the wing portions  144  and  154  of the first and second blades  140  and  150  interposed therebetween. For more firm position fixing, in the present exemplary embodiment, position fixing holes  145  and  155  are formed in the wing portions  144  and  154  of the first and second blades  140  and  150  and position fixing protrusions  115  inserted in the position fixing holes  145  and  155  are formed on the blade installation portion  114  of the main body  110 . Also, position fixing recesses  125  engaged with the position fixing protrusions  115  are formed in the protruding portion  124  of the cover  120 . 
         [0056]    In the present exemplary embodiment in which the first and second blades  140  and  150  are separately formed, the position fixing holes  145  and  155  are respectively formed at the first and second blades  140  and  150 . Accordingly, the position fixing protrusions  115  and the position fixing recesses  125  are respectively formed at four positions of each of the blade installation portion  114  and the protruding portion  124 . In the present inventive concept, the shape, position, and number of the position fixing protrusions and the position fixing holes are not limited to the above descriptions. 
         [0057]    Accordingly, the positions of the first and second blades  140  and  150  are stably fixed in the main body  110 . In particular, the first and second blades  140  and  150  may be prevented from being twisted at the fixed positions during the cutting of soft tissue. In addition, according to the above-described blade position fixing structure according to the present exemplary embodiment, the determination of the positions of the first and second blades  140  and  150  in the process of assembling the first and second blades  140  and  150  and the cover  120  to the main body  110  is made easy so that assembly convenience may be improved. 
         [0058]    Also, in the present exemplary embodiment, the first and second blades  140  and  150  formed of metal are manufactured separately from the main body  110  formed of plastic. However, the first and second blades  140  and  150  formed of metal may be integrally formed by injection molding with the main body  110  formed of plastic. That is, the coupling method of the first and second blades  140  and  150  and the main body  110  is not limited to the above-described method. 
         [0059]    As described above, according to the present inventive concept, since the dental instrument for cutting soft tissue employs a dual blade structure of the first and second blades having different cutting depths, the soft tissue arranged at a predetermined depth under the outer surface in the oral cavity may be easily and simply cut so that a soft tissue transplantation surgery may be facilitated. 
         [0060]    While the inventive concept has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood that various changes in form and details may be made therein without departing from the spirit and scope of the following claims. 
       INDUSTRIAL APPLICABILITY 
       [0061]    The present inventive concept can be applied to the technical field of a dental instrument for cutting soft tissue in the oral cavity.