Abstract:
Impression trays for taking dental impression of a subject are discussed herein with particular discussion extended to impression trays know as triple trays. Triple trays are so coined for their ability to simultaneously capture the upper and lower impressions and the bite registration of a subject during a same dental procedure. The trays described elsewhere herein incorporate features that strengthen or increase the rigidity of the frame so that an impression taken of the dentition of the subject using one of the trays described elsewhere herein is not distorted and is therefore an accurate reflection of the true dentition.

Description:
CROSS REFERENCE  
       [0001]     This application claims the benefit of U.S. provisional patent application No. 60/598,339, filed Aug. 2, 2004, entitled “Dental Impression Trays”, the content of which is hereby expressly incorporated by reference in its entirety. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to dental impression trays for taking dental impressions of a subject in general. Specifically, the present invention relates to dental impression trays known as triple bite trays.  
       BACKGROUND OF THE INVENTION  
       [0003]     Triple bite trays or triple trays are well known in the dental art for taking impressions of patients&#39; dentitions. Triple trays are so coined for their ability to simultaneously capture the upper and lower impressions and the bite registration of a subject during a same dental procedure.  
         [0004]     While triple trays are popular among practitioners, some conventional triple trays have problems with distortion. Distortion, as can be expected, is undesirable because it results in an incorrect mold of the subject&#39;s dentition, which then leads to an incorrect model of the dentition made by pouring, for example, plaster into the incorrect mold.  
         [0005]     Accordingly, there is a need for triple trays with greater resistance to distortion.  
       SUMMARY OF THE INVENTION  
       [0006]     The present invention may be implemented by providing a triple tray for taking an impression of a dentition including an inner wall, an outer wall having a handle attached thereto, and a screen connected to both the inner wall and the outer wall and defining at least one channel; a plurality of ribs disposed along at least one surface of the outer wall and at least one surface of the inner wall; and wherein the handle includes a dimple defined by a tapered ramp having a tapered surface having a radially outwardly incline from a flat portion of the handle towards a periphery of the handle.  
         [0007]     In one aspect, the plurality of ribs are disposed along at least one of an inner wall surface of the outer wall and the inner wall surface of the inner wall for facilitating gripping by an impression material.  
         [0008]     The present invention may also be practiced by providing a triple tray for taking an impression of a dentition including an inner wall, an outer wall having a handle attached thereto, and a screen connected to both the inner wall and the outer wall; a plurality of ribs disposed along at least one of an inner wall surface of the outer wall and the inner wall surface of the inner wall for facilitating gripping by an impression material; wherein a plurality of openings separate the inner wall surface of the inner wall from an outer wall surface of the inner wall, a plurality of lateral walls connected to both the inner wall surface and the outer wall surface of the inner wall, separating one opening from another opening, and wherein the handle includes a dimple defined by a ramp comprising an inclined surface extending adjacent a periphery of the handle.  
         [0009]     The present invention further provides a triple tray for taking an impression of a dentition including a metal frame having a first elongated portion, a curved portion, a second elongated portion, and a post attached to a plastic handle having a first retaining wall, a receiving bore, and a dimple defined by a ramp including an incline extending along a periphery of the handle, wherein the post is received in the receiving bore and wherein a screen is attached to the first elongated portion, the curved portion, and the second portion of the metal frame to define an upper channel and a lower channel.  
         [0010]     In one embodiment, the first retaining wall may include a plurality of ribs disposed along an inner wall surface of the wall for facilitating gripping by an impression material.  
         [0011]     In another embodiment, at least a portion of the first elongated portion may include a polymeric sleeve.  
         [0012]     In one aspect, at least a portion of the first elongated portion may be over-molded with a polymeric sleeve. In another aspect, at least a portion of the first elongated portion may be enclosed by the polymeric sleeve.  
         [0013]     In one embodiment, at least a portion of the first elongated portion may be secured to a second retaining wall. In one aspect, the second retaining wall may include a plurality of ribs disposed along at least a portion of an inner wall surface of the retaining wall.  
         [0014]     Other aspects and advantages of the present invention may be understood and practiced by reviewing the following description and the figures appended hereto. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]     These and other features and advantages of the present invention will become appreciated as the same become better understood with reference to the specification, claims and appended drawings wherein:  
         [0016]      FIG. 1  is a semi-schematic perspective view of a full arch tray provided in accordance with aspects of the present invention;  
         [0017]      FIG. 1   a  is a semi-schematic perspective view of the full arch tray of  FIG. 1  shown with alternative ribbing configuration;  
         [0018]      FIG. 2  is a semi-schematic end view of the full arch tray of  FIG. 1  without the screen for clarity;  
         [0019]      FIG. 3  is a semi-schematic side view of the full arch tray of  FIG. 1 ;  
         [0020]      FIG. 4  is a semi-schematic perspective view of a three-quarter tray provided in accordance with aspects of the present invention;  
         [0021]      FIG. 5  is a semi-schematic plan view of the tray of  FIG. 4 ;  
         [0022]      FIG. 6  is a semi-schematic perspective view of an anterior tray provided in accordance with aspects of the present invention;  
         [0023]      FIG. 6A  is a semi-schematic top view of the anterior tray of  FIG. 6  without the screen at the rear channel;  
         [0024]      FIG. 7  is a semi-schematic perspective view of a posterior tray provided in accordance with aspects of the present invention;  
         [0025]      FIG. 7   a  is a perspective view of the non-metal portion of the tray of  FIG. 7 ;  
         [0026]      FIG. 7   b  is a perspective view of a sleeve portion of the tray of  FIG. 7 ;  
         [0027]      FIG. 7   c  is a perspective view of the metal portion of the tray of  FIG. 7   c;    
         [0028]      FIG. 8  is a semi-schematic perspective view of the tray of  FIG. 7  from a different perspective;  
         [0029]      FIG. 9  is a semi-schematic plan view of the tray of  FIG. 7 ;  
         [0030]      FIG. 10  is a perspective view of the handle without a bore; and  
         [0031]      FIG. 11  shows a perspective view of an embodiment of a posterior tray of the present invention; and  
         [0032]      FIG. 12  shows a top view of the tray of  FIG. 11  of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0033]     The detailed description set forth below in connection with the appended drawings is intended as a description of the presently exemplified embodiments of a triple tray provided in accordance with practice of the present invention and is not intended to represent the only forms in which the present invention may be constructed or utilized. The description sets forth the features and the steps for constructing and using various triple trays of the present invention in connection with the illustrated embodiments. It is to be understood, however, that the same or equivalent functions and structures may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention. Also, as denoted elsewhere herein, like element numbers are intended to indicate like or similar elements or features.  
         [0034]     Impressions of patients&#39; teeth may be produced for a variety of purposes such as the manufacture of appliances for bite registrations, crown and bridge constructions, and the like. The present invention includes various types of impression trays adapted for use by a dentist for specific applications. These tray types may include a posterior, an anterior, a full arch, a three-quarter arch and a quadrant tray. The tray may be used simply as a carrier for an impression-forming material and to facilitate the placing and removal of the impression material in and from a patient&#39;s mouth.  
         [0035]     In use, the tray is filled with a pliable, uncured composite such as a silicone impression material or a polyether impression material and is seated in a patient&#39;s mouth until the material sets or cures. This generally takes a few minutes&#39; time.  
         [0036]     The impression tray of the present invention provides sufficient rigidity to produce a good impression by minimizing distortion of the impression when the material laden tray is removed from a patient&#39;s mouth. An accurate negative impression of the tooth or teeth selected for a dental procedure may then be used to form an accurate duplicate of the patient&#39;s dentition, following which a dental appliance may be produced on a stone model or similar.  
         [0037]     0.  
         [0038]     In one embodiment, as exemplified in  FIG. 1 , where a semi-schematic perspective view of a full arch dental impression tray is provided in accordance with aspects of the present invention. The tray  10 , as shown, is a full arch tray, useful for taking a full dentition of a patient&#39;s mouth, and is, for example, symmetrical about the parting line L. The tray  10  includes a buccal wall or outer wall  12 , a lingual wall or inner wall  14 , a screen  16  interconnecting the two walls, and a handle  18  attached to the outer wall  12 . The inner and outer walls define a channel  20  for receiving a curable impression material adapted for biting down by a patient to capture the patient&#39;s dentition. As is readily apparent, impression material may be applied to the channel  20  on both the top channel  20 A and the bottom channel  20 B. Any suitable impression material, including those already in the market or disclosed in prior art, for example, alginate, polyvinyl siloxane, polyether, and super-hydrophilic VPS, just to name a few, may be used with the tray  10 .  
         [0039]     The screen  16  acts as a retaining base for the impression material and may be made of any non-woven material or weaved material that is sufficiently thin to minimize the likelihood of obstructing a patient teeth during full occlusion and to not impede the making of an accurate bite on the impression material, i.e., to not prevent the upper and lower teeth from meeting. In one exemplary embodiment, the screen may be made of any woven or any non-woven material, for example, spun-bound polyester, having, for example, an average thickness of about 2.5 mil (0.06 mm) to about 5.5 mil (0.15 mm), and more for example, from about 3.5 mil (0.09 mm) to about 4.5 mil (0.11 mm). An example of a woven material may be a cotton gauze, available from Poon Cheung Kee Cotton Factory in China, a nylon mesh material or other equivalent materials. Examples of non-woven material may include those disclosed in U.S. Pat. Nos. 3,853,659; 4,340,563; 4,405,297; 4,692,106; and 5,431,986, and made commercially available from Cerex Advanced Fabrics of Cantonment, Fla. The contents of these patents are expressly incorporated herein by reference as if disclosed in full.  
         [0040]     The outer wall  12  includes an outer wall surface  22  and an inner wall surface  24 . A plurality of ribs  26  adorns the inner wall surface  24  of the outer wall  12 . The plurality of ribs  26  provides surfaces for the curable impression material to adhere or attach to so that the same does not shift or separate from the tray during the impression procedure and helps to minimize distortion. In one exemplary embodiment, the ribs  26  may be substantially evenly-spaced along the inner surface  24  of the outer wall  12  and each rib may include rounded ends  28 . In another embodiment, the ribs  26  may be irregularly or randomly spaced along the inner surface  24  of the outer wall  12 .  
         [0041]     In one exemplary embodiment, the plurality of ribs  26  may be generally of substantially the same height with the exception of the ribs near the edge or ends  30  of the outer wall  12 , which may be made successively shorter to correspond with the, for example, tapered portions of the two ends of the outer wall  12  if present. The ends  30  of the outer wall  12  may be tapered to minimize or prevent injuries to the gingival areas of the mouth when the tray is used to take an impression of the subject&#39;s dentition.  
         [0042]     The inner wall  14  includes an inner wall surface  32  and an outer wall surface  34 . In one embodiment, a plurality of ribs  26  may also adorn the wall of the inner wall surface  32 , also for facilitating gripping or adhesion by the curable impression material. In one aspect, the ribs  26  may also have rounded ends and may be substantially evenly-spaced along the inner wall surface  32  of the inner wall  14 . A plurality of elliptical openings  36  separate the inner wall surface  32  from the outer wall surface  34 . The lateral walls  38  between the openings  36  may function as ribs to increase rigidity of the inner wall  14 , and help to minimize distortion. The openings  36  may vary in size, shape, and number, provided that a sufficient number and/or wall thickness are incorporated for rigidity. A rear channel  40 , defined by the arcuate inner wall  14  and the screen  16 , is not intended to hold, although may hold, curable impression material but rather to add to the structural rigidity of the tray  10  along the radial direction.  
         [0043]     In other embodiments, such as that shown in  FIG. 1   a , the ribs  26  may be present in a substantially longitudinal direction  106 , a substantially transverse direction  108 , and combinations thereof. In the  FIG. 1   a  embodiment, only a few representative ribs in various rib configurations are shown for clarity although it is readily recognized that an array of spaced apart ribs in various configurations may be incorporated. In other embodiments, at least one of the ribs  106 ,  110  may be located substantially centrally along the outside surface  22  of the outside wall  12  and the outside surface  34  of the inner wall  14 , substantially proximate the parting line L. In still further embodiments, at least one of the ribs  112  may also be present along the outer edge of at least one of the inner surface  32  of the inner wall  14 , the outer surface  34  of the inner wall  14 , the inner surface  24  of the outer wall  12 , and the outside surface  22  of the outer wall  12 . As noted above, the ribs, whether present in vertical or horizontal configuration, may contribute to added stiffness of the tray  10  so that the walls may be constructed sufficiently thin without compromising the desired stiffness of the tray.  
         [0044]     In one embodiment, at least one rib may adorn the upper and lower edges of the outer wall surface  22  of the outer wall  12 , and the upper and lower edges of the outer wall surface  34  of the inner wall  14 , in lieu of or addition to the plurality of ribs  26  present on the inner surface  24  of the outer wall  12  and the inner surface  32  of the inner wall  14 .  
         [0045]     In still another embodiment, at least one rib  114  adorns the outer wall surface  22  of the outer wall  12 , and the outer wall surface  34  of the inner wall  14 , along the longitudinal direction of the walls, in lieu of or in addition to the plurality of ribs  26  present on the inner surface  24  of the outer wall  12  and the inner surface  32  of the inner wall  14 .  
         [0046]     In still a further embodiment, at least one rib may adorn the outer wall surface  22  of the outer wall  12 , and the outer wall surface  34  of the inner wall  14  substantially centrally along the parting line L of the walls. Even though the ribs have been described in detailed with respect to the full arch above, they are equally applicable to the other arches described below.  
         [0047]     The oversized handle  18  may be, for example, attached or integrally molded to the outer wall surface  22  of the outer wall  12 . The handle  18  includes a base  41 , which extends from the outer wall surface  22  of the outer wall, and a dimple  42  which may be formed by incorporating a ramp  44  along the periphery  46  of the handle  18 , and may, for example, resemble an amphitheatre. The dimple generally makes the tray easier to grip. In another example, the ramp  44  includes an arcuate section that has a tapered width extending along the periphery  46  of the handle in a generally U-shaped configuration. The tapered section originates at about the flat section  48  of the handle  18  and inclines as it extends radially outwardly. The ramp  44  facilitates gripping of the tray  10  by a user and the inclined section of the ramp provides a physical barrier for gripping by the user. As is readily apparent, an identical ramp  44  may be provided on the second side of the handle  18 . In another exemplary embodiment, the ramp may have an incline of about 3 to about 30 degrees from horizontal. In an exemplary embodiment, the ramp  44  has a non-linear incline or a curved incline. An optional bore  43  for hanging the tray  10  or through which a tag or label (not shown) having personal identification and/or other personal information of the patient may be inserted may be included.  
         [0048]     The base section  41  of the handle  18  is, for example, sufficiently large to further add to the structural rigidity of the outer wall  12 . In an exemplary embodiment, the base section  41 , at the point of attachment with outer wall  12 , includes a width equivalent to about 10% to about 30% of the arc surface of the outer wall  14 . The handle may also be provided with a writable surface on a portion thereof for recording the personal information of a patient. The writable portion may be raised, indented or flush with the rest of the handle. The portion is generally of the same material as the rest of the handle. It may also be separately treated or coated for better writability, i.e., for recording information.  
         [0049]     In one exemplary embodiment, to construct a tray  10  with minimal flex or distortion when the patient bites down on the curable impression material, the tray  10  may be made from any polymer including a polystyrene (such as STYRON™ 685D, or STYRON™ A-TECH™, available form Dow Chemical Company); a polyolefin such as polyethylene, polypropylene, and polybutylene; a polyester such as polyethylene terephthalate, or polybutylene terephthalate; a polyamide, such as Nylon 66w; an acrylic polymer; polyvinylchloride; polyetherimide like ULTEM®; a polycarbonate or polycarbonate (PC) blends such as a polymeric alloy like Xenoy® resin, which is a composite of polycarbonate and polybutyleneterephthalate or Lexan® plastic, which is a copolymer of polycarbonate and isophthalate terephthalate resorcinol resin (all available from GE Plastics); other rigid materials including polyformaldehyde (available as DELRIN®), polyaryletheretherketone (PEEK), polyphenylene sulphide, acrylonitrile butadiene styrene (ABS), polyacetals; liquid crystal polymers, such as an aromatic polyester or an aromatic polyester amide containing, as a constituent, at least one compound selected from the group consisting of an aromatic hydroxycarboxylic acid (such as hydroxybenzoate (rigid monomer), hydroxynaphthoate (flexible monomer), an aromatic hydroxyamine and an aromatic diamine, (exemplified in U.S. Pat. Nos. 6,242,063, 6,274,242, 6,643,552 and 6,797,198, the contents of which are incorporated herein by reference), polyesterimide anhydrides with terminal anhydride group or lateral anhydrides (exemplified in U.S. Pat. No. 6,730,377, the content of which is incorporated herein by reference) or combinations thereof.  
         [0050]     In addition, any polymeric composite such as engineering prepregs or composites, which are polymers filled with pigments, carbon particles, silica, glass fibers, conductive particles such as metal particles or conductive polymers; or mixtures thereof may also be used. For example, a blend of polycarbonate and ABS (Acrylonitrile Butadiene Styrene), a mixture of polyamides, such as nylon 66w and fiberglass material, may be used.  
         [0051]     In an exemplary embodiment, the wall thickness of the outer wall  12  and the inner wall  14  may be, for example, about 1/32″ (about 0.8 mm) to about ¼″ (about 6 mm) thick, more for example, about 1/16″ (about 1.5 mm) to about ⅕″ (about 5 mm). In general, the combination of ribs, their location and arrangement, the thickness of the walls as well as the type of material used in their construction, all may contribute to the desired stiffness. Thus, if the ribs are strategically located, the material choice may not be as critical, and polymers and composites including polymers such as polyethylene terephthalate, polybutylene terephthalate, polystyrene, or polypropylene, maybe used in the construction of the trays. In fact, if the ribs are strategically located, the thickness of the walls may actually be decreased without compromising the rigidity. In addition, a combination of different materials and composites may be used in making different components of the tray, such as making the outer wall  12  from one material and the inner wall  14  from a composite. Also, the thickness of the walls may not be uniformly across the wall. In one embodiment, the wall may also be tapered towards the edges.  
         [0052]     In one exemplary embodiment, the tray  10  may be made by co-molding the inner wall  14 , the outer wall  12 , and the handle  18  with the screen  16 . In another exemplary embodiment, the tray  10  may be made from a separate upper tray part  50  and lower tray part  52  and snap-fit together along the centerline L via a plurality of detent engagements. In a further embodiment, the tray  10  may be made from a separate upper tray part  50  and lower tray part  52  and attached together using heat seal or an adhesive.  
         [0053]     Referring now to  FIG. 2 , an end view of the tray  10  looking from the perspective of the rear channel  40  of the outer wall  14  towards the inner wall surface  24  of the outer wall  12  is shown, without the screen  16  for clarity. As can be seen, the wall dimension or height measured from the parting line L for the inner wall  14  may be different than the wall dimension measured from the parting line L for the outer wall  12 . The outer wall  12  is higher or greater than the inner wall  14  as shown, and as the patient bites down on the curable impression material, the curable material may not flow extra-orally or outside of the mouth. However, some amount of over flow of curable impression material flowing from the main channel  20  into the rear channel  40  when an impression is taken may occur.  
         [0054]     Although not shown, the tray  10  may be made proportionately smaller for taking the full dentition of a smaller person or made larger for a larger person.  
         [0055]     Referring now to  FIG. 3 , a side view of the tray  10  is shown. In one exemplary embodiment, the handle  18  includes a width at its rear section  54  that is larger than the width at its neck section  41 . As is readily apparent to a person of ordinary skill in the art, the added width is due to the additional width of the tapered wall section or ramp  44 . In comparison to the width of the outer wall  12 , the width at the rear section  54  has a width that is, for example, about 20% to about 50% of the width of the outer wall, more for example, about 25% to about 35%. The width at the neck section  41  is, for example, about 10% to about 40% of the width of the outer wall, more for example, about 15% to 25%.  
         [0056]     Without wishing to be bound to a theory, it is surmised that the wide handle, for example, the width of the neck section of the handle, may also contribute to the rigidity of the trays to minimize distortion of any impressions made.  
         [0057]     Referring now to  FIG. 4 , a three quarter tray  56  (herein ¾-tray) for taking ¾ of a dentition is shown. The ¾-tray  56  is similar to the full arch tray  10  described above with reference to  FIGS. 1-3  with the exception that a portion of the outer wall  60  and the inner wall  62  on one side of the plane defined by the centerline of the handle  18 , along the lengthwise direction, have been reduced or shortened. The ¾ tray  56  may be configured to take an impression of an entire one side of the upper and lower teeth and through the first bicuspid of the other side of the upper and lower teeth, thus so named ¾ tray. Thus, the amount or portion of the outer and inner walls to be shortened to make the ¾ tray is dependent on the amount of tray necessary to take an impression of an entire one side of the dentition and through the first bicuspid of the other side of the teeth. A bigger person may also need a bigger ¾ tray than a smaller person. The outer wall  60  and inner wall  62  of the ¾ tray  56  may have points that substantially terminate or align along a linear line  58  defined by the edge of the screen  16 .  
         [0058]     Referring now to  FIG. 5 , a top plan view of the ¾ tray  56  of  FIG. 4  is shown. In an exemplary embodiment, the base section  41 , at the point of attachment with outer wall  60 , includes a width equivalent to, for example, about 25% to about 45% of the arc surface of the outer wall  60 . The handle  18  is otherwise the same as the handle of  FIGS. 1-3  and includes a amphitheatre or dimple  42 , defined by the ramp  44 . In one exemplary embodiment, the end or tip  64  of the outer wall  60  at the shortened side of the wall may also be tapered, as shown in  FIG. 4 , in the same manner as the taper shown in  FIG. 1 .  
         [0059]     Referring now to  FIG. 6 , an anterior tray  66  for taking an impression of the anterior (incisor and cuspid) portion of a patient&#39;s dentition is shown. The anterior tray  66  is similar to the full arch tray  10  described above with reference to  FIG. 1 , except that the wall portions of the outer wall  68  and the inner wall  70  do not extend as far from the origin  72  or tip of the inner and outer walls. The arc length of the inner and outer walls  68 ,  70 , may extend from the origin  72  a sufficient amount to enable coverage of the anterior portion of the patient&#39;s dentition. In one exemplary embodiment, the handle  18  is of the same size and configuration as the handle of  FIGS. 1-3 . here again, a bigger size may be needed for a bigger person and a smaller size for a smaller person.  
         [0060]      FIG. 6A  is a semi-schematic top plan view of the anterior tray  66  of  FIG. 6 . In the figure shown, the screen  16  is absent from the rear channel  40 , which may be an alternative method for practicing the triple trays including comprising a rear channel of the present invention.  
         [0061]      FIG. 7  is an isometric view of a posterior tray  74  for taking an impression of the posterior (bicuspid and molar) portion of a patient&#39;s dentition. In the orientation shown, the tray  74  is designed to take an impression of the posterior portion of the right side of the patient&#39;s dentition. By turning the same tray  74  upside-down, it may be used to take an impression of the left side of the patient&#39;s dentition.  
         [0062]     The tray  74  may be a hybrid in that it may include portions made from plastic and portions made from metal. The plastic portion or portions may include any of the above mentioned polymer or polymeric composites, for example, polystyrene or a composite such as nylon 66w with 40% by weight fiberglass. The metal portion or portions may be of any light weight metal having structural integrity, and may include, but not limited to aluminum; stainless steel; magnesium or its alloys; brass; copper; an alloy such as Ni/Ti alloy; any amorphous metals including those available from Liquid Metal, Inc. or similar ones, such as those described in U.S. Pat. No. 6,682,611, and U.S. Patent Application No. 2004/0121283, the entire contents of which are incorporated herein by reference, or combinations thereof.  
         [0063]     The metal portion may include an elongated U-shaped frame  76 , which has a first elongated portion  78 , a curved portion  80 , and a second elongated portion  82  including a post  84 , as shown in  FIGS. 7 and 7   c . The curve portion  80  of the frame  76 , for example, may include a flat portion or surface having a width sufficiently thin to fit between the gums behind the second or third molars when bit down by a subject.  
         [0064]     The polymeric portion of the tray  74 , as shown in  FIGS. 7 and 7   a , may include a handle portion  18 , a receiving bore  86 , and a retaining wall  88 , which, in the presently exemplified embodiment, may include a single integrally cast or molded piece or separately cast or molded parts and then assembled into one piece. In one exemplary embodiment, the retaining wall  88  may include a first section  90  adjacent the handle  18  and a second section  94  opposite the first section  90 . The first section  90  includes a tapered edge which may taper from a central portion  92  of the retaining wall  88  towards the substantially flat section  48  of the handle  18 . The second section  94  includes a curved corner adapted for helping to eliminate or minimize sharp edges that may otherwise cause discomfort to the user of the tray  74 . In one exemplary embodiment, the wall  88  may also be slightly curved to correspond to the posterior portion of the dentition.  
         [0065]     The U-shaped frame  76  may be assembled to the handle  18  by inserting the post  84  into a receiving bore  86  of the plastic handle  18 . The post  84  and the receiving bore  86  may incorporate detents for a secured connection. Alternatively, the post  84  may be secured to the receiving bore  86  using glue or adhesive. In another embodiment, the U-shaped frame and the handle  18  may be integrally molded, for example, by over-molding a polymeric sleeve over portions of the U-shaped metal frame.  
         [0066]     In one embodiment, the first elongated portion  78  of the U-shaped frame may be covered with a polymeric portion  78   a , as shown in  FIGS. 11 and 12 , or uncovered, as shown in  FIG. 7, 8  or  9 .  
         [0067]      FIG. 7   c  shows a perspective view of the U-shaped frame  76  prior to its attachment to the polymeric portion of the tray. In an exemplary embodiment, the frame  76  is hollow and may have a slit or a channel  96  extending the length of the interior surface of the frame  76 . The screen  16  may be then placed in the slit  96  and pinched down to secure the screen to the frame. In an alternative embodiment, the frame  76  may include a core such that the frame is not hollow or is coreless.  
         [0068]      FIG. 7   b  shows a perspective view of a polymeric sleeve  78   a  including a bore  78   b  throughout its length for fitting around the first elongated portion  78  of the U-shaped frame  76 , shown in  FIG. 7   c . As noted above, the arch  78   a  may be formed separately from the U-shaped frame and then assembled afterwards onto at least a portion of the first elongated portion  78 , or it may be integrally molded, for example, over-molded onto at least a portion of the first elongated portion  78  of the U-shaped frame  76 . The assembled structures are exemplified in  FIGS. 11 and 12 .  
         [0069]     The outer arch  78   a  may also include a retaining wall  78   c , which is exemplified as an integrally cast or molded piece, as shown in  FIG. 7   b . In one embodiment, the retaining wall  78   c  may be tapered towards at least one of the ends.  
         [0070]      FIG. 11  shows a perspective view of one embodiment of the posterior tray which may have structures similar to those described above, for example, in  FIG. 7 . In addition, at least a portion of the first elongated portion  78  is covered with a polymeric sleeve  78   a . The sleeve  78   a  may be integrally molded to the first elongated portion  78  and has a retaining wall  78   c , as mentioned above, in one embodiment. In another embodiment, the sleeve  78  may be separately constructed with a retaining wall  78   c , and a bore  78   b  throughout its length, through which the first elongated portion  78  may be inserted.  
         [0071]      FIG. 12  shows the top view of the embodiment of  FIG. 11 . In the orientation shown, the retaining wall  88  is shown to have a curvature that matches the curvature of the second elongated section  94  of the U-shaped frame  76 . In one exemplary embodiment, the retaining wall  88  is not physically attached to the U-shaped frame  76  or the second elongated section  94  of the U-shaped frame. In another exemplary embodiment, the retaining wall  88  may incorporate means for attaching the second portion  94  or the central portion  92  of the wall to the frame  76 . Such means include glue, adhesive, or detents.  
         [0072]     In this embodiment, the screen material  16 , which may be woven or non-woven, as noted above, may be attached or bounded to the posterior tray only about the polymeric portion  82  and the polymeric sleeve  78   a . A hole may be present towards the free end of the polymeric sleeve  78   a , adapted for receiving a hanging label (not shown), having a patient&#39;s vital information.  
         [0073]     In one exemplary embodiment, the handle  18  may include a dimple section  42  defined by the ramp  44 , as previously discussed.  
         [0074]     Referring now to  FIG. 8 , the screen  16  is shown to be attached to the U-shaped frame  76 . In an exemplary embodiment, the frame  76  is hollow and may have a slit or a channel  96  extending the length of the interior surface of the frame  76 , as discussed above in  FIG. 7   c . The screen  16  may be then placed in the slit  96  and pinched down to secure the screen to the frame. In an alternative embodiment, the frame  76  may include a core such that the frame is not hollow or is coreless.  
         [0075]     In one exemplary embodiment, the retaining wall  88  similarly may include a gap or a slit  98  along at least a portion of its centerline. The screen  16  slides between the slit  98  when the U-shaped frame  76  is assembled to the handle  18  by inserting the post  84  into the receiving bore  86  of the handle  18 . Similar to the other tray embodiments discussed elsewhere herein, the retaining wall  88  includes a plurality of spaced-apart ribs  26 .  
         [0076]      FIG. 9  is a top view or plan view of the posterior tray  74 . In the orientation shown, the retaining wall  88  as shown has a curvature that matches the curvature of the second elongated section  94  of the U-shaped frame  76 . In one exemplary embodiment, the retaining wall  88  is not physically attached to the U-shaped frame  76  or the second elongated section  94  of the U-shaped frame. In another exemplary embodiment, the retaining wall  88  may incorporate means for attaching the second portion  94  or the central portion  92  of the wall to the frame  76 . Such means include glue, adhesive, or detents.  
         [0077]     In one exemplary embodiment, the handle  18  includes a dimple section  42  defined by the ramp  44 , as previously discussed. However, the base section  41  of the handle  18  may be slightly narrower than the handle any may incorporate the receiving bore  86 . Overall, the tray  74  may be sized so that the posterior portion of a subject&#39;s dentition may be taken. The tray  74 , and other trays discussed elsewhere herein, may incorporate a silver, white, blue, or red finish or other colors to be determined during manufacturing of the tray. A tray may also be used with a bigger person, and a smaller tray may be used with a smaller person, as noted before.  
         [0078]     The U-shaped frame  76  may be made of any metal or metallic alloy, as discussed above. In one embodiment, the U-shaped frame may be made from a flattened wire, which may be formed by using any impact forces such as coining or stamping. The flattened wire has an added advantage of having smooth surfaces for patient comfort even if the polymeric sleeve  78   a  is absent from the construction. In another embodiment, the U-shaped frame may be cast or molded. In a further embodiment, the U-shaped frame may be machined. In some embodiments, the metallic parts may have to be de-burred to minimize any sharp edges.  
         [0079]     As with the description of the ribs, the description of other tray parts, such as the handle  18  and the different materials that may be used to mold the tray, with respect to the full arch is equally applicable to all the other arches and embodiments described elsewhere herein. Also, although the exemplified embodiments of the invention have been described with some specificity, the description and drawings set forth herein are not intended to be delimiting, and persons of ordinary skill in the art will understand that various modifications may be made to the embodiments discussed herein without departing from the scope of the invention, and all such changes and modifications are intended to be encompassed within the appended claims. Various changes to the triple trays described elsewhere herein may be made including changes to the size of the tray, the number of ribs, the spacing of the ribs, the slope or taper of various structures, the absence of a bore on the handle, such as shown in  FIGS. 7   a ,  10  and  11 , and the type of screen to be used. Accordingly, many alterations and modifications may be made by those having ordinary skill in the art without deviating from the spirit and scope of the invention.