Abstract:
A method to form a mouthguard, said method including the steps of providing a mould ( 14 ) to which a mouthguard shell ( 16 ) is applied. A sheet member ( 21 ) of resilient material is applied to the shell ( 16 ) and plastically deformed by applying a pressure differential across the sheet to thereby urge the shell ( 16 ) into contact with the mould ( 29 ) to plastically deform the shell ( 16 ) to form a mouthguard.

Description:
TECHNICAL FIELD 
   The present invention relates to mouthguards and more particularly, but not exclusively, to mouthguards used by sport participants. 
   BACKGROUND OF THE INVENTION 
   Mouthguards have consisted of a number of types, including those constructed of thermoplastics material, which are heated (typically in hot water) and then applied to the user&#39;s mouth so that the mouthguard is moulded to fit the user&#39;s teeth and jaw. A more expensive type of mouthguard is as provided generally by dentists. The dentist “custom fitted” mouthguards are manufactured from an impression taken of the user&#39;s teeth and jaw. A sheet of plastics material is placed over the impression and plastically deformed thereto by the use of heat and pressure. 
   The custom fitted mouthguards discussed above suffer from the disadvantage that there is not incorporated within the mouthguard features desirable for improving the level of protection for the user. 
   OBJECT OF THE INVENTION 
   It is the object of the present invention to overcome or substantially ameliorate the above disadvantage. 
   SUMMARY OF THE INVENTION 
   The present invention is a method to form a mouthguard to be worn by a user, the method includes the steps of:
         providing a mould having a portion configured as a reproduction of a portion of a user&#39;s mouth;   locating on the mould a mouthguard shell to be plastically deformed by pressure to conform to said portion;   placing over the shell a deformable sheet so that the shell is located between the sheet and mould; and   applying a pressure differential across the sheet so that the sheet urges the shell against the mould to plastically deform the shell against said portion so that the mouthguard conforms to the configuration of the user&#39;s mouth.       

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A preferred form of the present invention will now be described by way of example with reference to the accompanying drawings wherein: 
       FIG. 1  is a schematic perspective view of an apparatus to deform a mouthguard shell to the configuration of a mould; 
       FIG. 2  is a schematic part section side elevation of the apparatus mould and mouthguard shell of  FIG. 1 , in a first configuration; 
       FIG. 3  is a schematic part section side elevation of the apparatus, mould and mouthguard shell as illustrated in  FIG. 2  in a further configuration; 
       FIG. 4  is a schematic section side elevation of an alternative sheet member employed in the apparatus of  FIG. 1 ; and 
       FIG. 5  is an isometric view of the mouthguard shell of  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Described in International Patent Application PCT/AU99/00458 are a number of mouthguard shells (bodies) which can be plastically deformed so as to conform to the configuration of a user&#39;s mouth. The mouthguard shells disclosed in this international patent application may be employed in the apparatus  10  of  FIGS. 1 to 3 . However, in this respect it should be appreciated that the mouthguard shell described herein is formed from a suitable mouldable material and need not be a shell as described in the above PCT application. 
   In the accompanying drawings there is schematically depicted an apparatus  10  within which a mouthguard is formed. The apparatus  10  includes a base  11  from which there upwardly extends three posts  12 . Inserted over the posts  12  is a sealing ring  13  which has apertures  14  through which the posts  12  pass. 
   The base  11  receives a mould  29  to deform the mouthguard shell  16 . The mould  15  has a portion  17  produced from an impression taken from a patient&#39;s mouth, particularly the teeth and gums. 
   The mouthguard shell  16  is of a “C” configuration and is of a “U” transverse cross section. Typically, the mouthguard shell  16  would have the shape and configuration as illustrated in the above-mentioned PCT specification. The mouthguard shell  16  would fit over the portion  17  so that the portion  17  is located between flanges  18  of the shell  16  and would in particular engage base  19  of the shell  16  to cause deformation thereof so that the mouthguard shell  16  conforms to the shape and configuration of the portion  17 . 
   Typically, the shell  16  would be heated prior to being placed on the portion  17 , so that when pressure is applied to the shell  16 , the shell  16  plastically deforms. To apply pressure to the shell  16  there is provided a sheet member  21  formed of resilient material such as plastics or rubber material. In this embodiment the sheet member  21  is of a circular configuration so as to rest on the annular lip  20 . To maintain the sheet member  21  in sealing contact with the ring  13  there is provided a clamp ring  22  which is of a similar configuration to the ring  13 . The ring  22  has apertures  23  through which the posts  12  pass. 
   The ring  13  has an annular step  24  providing the lip  20 . As best seen in  FIGS. 2 and 3  the member  21  is engaged within the step  24 . 
   The ring  23  has an annular projection  25  which is of a configuration to cooperate with the step  24  so that the member  21  has its annular periphery clamped between the rings  13  and  22 . If so required the ring  22  can be provided with a sealing ring  26 . 
   When the mouthguard shell  16  is to be deformed to form a mouthguard for the patient from which the impression has been taken, the shell  16  is heated and then placed on the portion  17 . The apparatus  10  with the shell  16  is then placed in a machine which applies a pressure differential across the member  21 . More particularly the machine includes a piston that engages with the upper surface  27  of the ring  22  and moves the rings  13  and  22  down into contact with the surface  28  of the base  11 . The piston sealingly engages the surface  27  and applies a gas (preferably air) under pressure to the upper surface of the member  21 . The member  21  then deforms about the shell  16  and forces the shell  16  onto the portion  17  to plastically deform the shell  16 . The pressure above the member  21  is released and the rings  13  and  22  raised so that an operator may then remove the formed mouthguard. 
   In an alternative embodiment the rings  13  and  22  may be moved into contact with the surface  28  and then air withdrawn from below the member  21  so that air pressure above the member  21  exerts a force on the shell  16  to deform the shell  16 . 
   In an alternative embodiment the member  21  may be preformed so as to be convex as illustrated in  FIG. 4 . This would aid in minimising or eliminating forces generated by stretching the member  21  over the shell  16 . In such an arrangement only the pressure differential across the member  21  would cause deformation of the shell  16 . 
   In the above described preferred embodiments the member  21  may be rubber, latex, silicone or any other suitable synthetic elastomeric material. In the above embodiment the member  21  is of a domed configuration. The member  21  is domed so as to extend away from the mould  15  (see  FIGS. 1 and 4 ). In an alternative embodiment, the member  21  may be formed of elastic foil.