Abstract:
The present invention provides a removable full or partial denture containing a linguoplate and metal occlusion of a restoring tooth or teeth with composite facing for restoring a tooth or teeth on the dental arch of a patient, wherein the denture utilizes a metal casting having the linguoplate, and at least one denture tooth on one side of the arch, and the at least one denture tooth is an extension of the linguoplate.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a removable full or partial denture containing a linguoplate and metal occlusion of a restoring tooth or teeth with composite facing for restoring a tooth or teeth on the dental arch of a patient. 
       BACKGROUND OF THE INVENTION 
       [0002]    Removable partial denture has been used through the years to replace teeth which are missing through accident and disease. The conventional partial denture has the metal framework of a metal casting which supports the acrylic teeth for missing teeth and acrylic flange for missing alveolcur bone structures and its mucosal lining. The conventional partial dentures for restoring missing teeth on the upper dental arch of the patients have a bar, strap or plate as a major connector which connects the components on one side of the dental arch to the components on the opposite side thereof, for examples anterior-posterior palatal bars, single palatal strap type, U-shaped palatal major connector, and palatal plate-type major connector. The degree of discomfort is even stronger for a patent wearing the conventional upper partial denture than who wearing the conventional lower partial denture, because the bar, strap or plate connecting both sides of the arch of the upper partial denture are right above the patient&#39;s tongue. The inventors of the present application in U.S. Pat. No. 6,896,516 B2 disclose a removal partial denture containing no lingual bar, and in particular to removable partial dentures containing no palatal bar or lingual bar for restoring teeth on the upper dental arch of a patient. 
         [0003]    The great challenge of the partial denture is to maintain the occlusal vertical dimension of mouth. Through the years of usage, due to the nature of acrylic teeth, this occlusal vertical dimension will be lost from the overuse of the acrylic teeth. 
       SUMMARY OF THE INVENTION 
       [0004]    A primary objective of the present invention is to provide a removable full or partial denture that does not have an acrylic tooth or teeth, which are replaced by a metal denture tooth or teeth cast together with a linguoplate. 
         [0005]    In order to accomplished the above-mentioned objective, a denture constructed in accordance with the present invention is in the form of an arch for restoring a tooth or teeth which are missing on a dental arch of a patient and comprises a metal casting comprising a linguoplate, and at least one denture tooth on one side of said arch, wherein said at least one denture tooth is an extension of said linguoplate. 
         [0006]    Preferably, the denture of the present invention further comprises a composite facing bonded to a facial surface of said at least one denture tooth. More preferably, the facial surface of said at least one denture tooth is polished or finished to have a roughness suitable for the bonding. 
         [0007]    Preferably, the denture of the present invention further comprises a resin material bonded to a surface opposite to an occlusal surface of said at least one denture tooth. More preferably, the resin material is further bonded to a surface opposite to a lingual surface of said linguoplate. 
         [0008]    Preferably, the surface opposite to an occlusal surface of said at least one denture tooth has one or more recesses or grooves for receiving the resin material, and said recesses or grooves have a reduced opening to enhance the bonding. More preferably, the surface opposite to a lingual surface of said linguoplate has one or more recesses or grooves for receiving the resin material, and said recesses or grooves have a reduced opening to enhance the bonding. 
         [0009]    Preferably, the resin material comprises a relatively rigid portion and a relatively soft portion, wherein the relatively rigid portion bonded to the surface opposite to an occlusal surface of said at least one denture tooth, and the soft port portion is bonded to the relatively rigid portion and is opposite to the surface of said at least one denture tooth for contacting a lining mucosa over a site or sites of the missing tooth or teeth. 
         [0010]    Preferably, said at least one denture tooth is solid. 
         [0011]    Preferably, said at least one denture tooth is hollow. 
         [0012]    Preferably, said metal casting further comprises a retention mesh protruding from the linguoplate and below said at least at one denture tooth, so that the retention mesh can be embedded in a resin material bonded to a surface opposite to an occlusal surface of said at least one denture tooth. 
         [0013]    Preferably, said metal casting further comprises an occlusal rest, a clasp, or both for engaging to a health tooth adjacent to the missing tooth of said patient, which are extended from the linguoplate. 
         [0014]    Preferably, the denture is a partial denture. 
         [0015]    Preferably, the denture is a full denture. 
         [0016]    Preferably, said metal casting is made of titanium or a titanium alloy. 
         [0017]    The titanium and titanium alloy has a hardness similar to that the natural teeth. The use of titanium metal occlusion to replace the traditional acrylic teeth has the advantage of keeping the occlusal vertical dimension better. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is a perspective view of a removable upper partial denture according to U.S. Pat. No. 6,896,516 B2. 
           [0019]      FIG. 2  is a perspective view of a removable upper partial denture according to a first preferred embodiment of the present invention, wherein parts or portions similar to those of the partial denture shown in  FIG. 1  are designated by like numerals. 
           [0020]      FIG. 3  shows a cross-sectional view of a removable partial denture made according to a second preferred embodiment of the present invention. 
           [0021]      FIG. 4  shows a cross-sectional view of a removable partial denture made according to a third preferred embodiment of the present invention. 
           [0022]      FIG. 5  show a cross-sectional view of a removable partial denture made according to a fourth preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The Removable Partial Denture 
       [0023]    For an illustration purpose, we borrow  FIG. 1  of U.S. Pat. No. 6,896,516 B2 to describe a first preferred embodiment of a removable partial denture made according to the present invention. As shown in  FIG. 1 , the removable partial denture disclosed in U.S. Pat. No. 6,896,516 B2 contains denture teeth  31  and  32 ; the resin material  40 ; and a metal casting  20 . The metal casting  20  is composed of two circumferential clasps  21 , three occlusal rests  22 , two bar clasps  23 , a linguoplate  10 , and two metal frame works  24 , wherein a portion of the two metal frame works  24  are embedded in the resin material  40 , and can not be seen in  FIG. 1 . The resin material  40  bonds the denture teeth  31  and  32  to the underlying metal frameworks  24 . The circumferential clasps  21  hold onto the natural teeth at both ends of the dental arch. The occlusal rests  22  and the bar clasps  23  fit into the under cut area of the labial or buccal surface of the natural teeth. The linguoplate  10  contacts all the teeth between the two denture teeth  31  and  32 . A removable partial denture made according to the first preferred embodiment of the present invention shown in  FIG. 2  is similar to the removable partial denture shown in  FIG. 1 , except that the metal casting  20  further contains metal denture teeth  31 ′ and  32 ′ which are cast together with the other portions of the metal casting  20 , so that the acrylic denture teeth  31  and  32  shown in  FIG. 1  are no longer needed. 
         [0024]      FIG. 3  shows a cross-sectional view of a removable partial denture made according to a second preferred embodiment of the present invention, wherein a porcelain or composite facing  100  is bonded to a facial surface of the metal denture tooth  31 ′ of the metal casting  20 . The porcelain or composite facing  100  preferably has a natural tooth color. The resin material  40  is bonded to a surface opposite to an occlusal surface of the denture tooth  31 ′ and a surface opposite to a lingual surface of the linguoplate  10 , on which recesses or grooves  110  are formed for receiving the resin material  40 , and said recesses or grooves have a reduced opening to enhance the bonding. 
         [0025]      FIG. 4  shows a cross-sectional view of a removable partial denture made according to a third preferred embodiment of the present invention, wherein the metal denture tooth  31 ′ is hollow unlike the solid metal denture tooth shown in  FIG. 2 . Similarly, the partial denture also has a porcelain or composite facing  100  bonded to a facial surface of the metal denture tooth  31 ′ of the metal casting  20 , and a resin material  40  is bonded to a surface opposite to an occlusal surface of the denture tooth  31 ′ and a surface opposite to a lingual surface of the linguoplate  10 . 
         [0026]      FIG. 5  shows a cross-sectional view of a removable partial denture made according to a fourth preferred embodiment of the present invention, wherein the metal denture tooth  31 ′ has a tissue-side housing  120  or is semi-hollow unlike the hollow metal denture tooth shown in  FIG. 3 . A relatively rigid resin material  41  such as acrylic resin is received and cured in the tissue-side housing  120  and a relatively soft resin material  42  such as an elastomer is bonded to the bottom of the relatively rigid resin material  41  for contacting a lining mucosa over a site of the missing tooth of the patient. Similarly, the partial denture also has a linguoplate  10 , and a porcelain or composite facing  100  bonded to a facial surface of the metal denture tooth  31 ′ of the metal casting  20 . 
       The Clinical Procedures 
       [0027]    The oral examination is taken. All the remaining teeth and its surrounding tissues are evaluated for their structural and functional stability. 
         [0028]    The preliminary impression is taken and poured for study model. Customized trays are prepared for final impression. 
         [0029]    The teeth are prepared for rest and path of insertion. Final impression is taken and poured for working models. 
         [0030]    Bite registration is taken and models are mounted on the articulator. It is sent to the laboratory with prescription which describes the design of the RPD. 
         [0031]    After the RPD framework (titanium) is back from the laboratory, the clinical trial is carried out for its fitness. 
         [0032]    The framework is back to the laboratory for application of the porcelain or composite facing. 
         [0033]    The second clinical trial is to evaluate its esthetic aspect of the RPD. 
         [0034]    The framework is sent back to the laboratory for final process of adding the acrylic resin base. The final clinical procedure is called the insertion which includes all the adjustments: the path of insertion, the occlusal adjustment, and the retention of the clasps. 
       The Characteristics of this New RPD 
       [0035]    The characteristics of this new partial denture design are 
         [0036]    1. The metal (titanium) occlusal surface replacing the acrylic resin occlusal surface for preventing the occlusal wear which causes the loss of vertical dimension of the occlusion. 
         [0037]    2. Hollow or semi-hollow main body, 
         [0038]    3. Porcelain or composite facing. 
         [0039]    Further, 
         [0040]    The device (RPD) intimately contacts gum tissue, increasing “suction” and “massaging” effects 
         [0041]    The device can be solid, hollow, or partially hollow. The device is preferably partially hollow. Preferably the hollow portion has a geometry with a reduced opening which can receive the elastic cushion (by slightly squeezing/elastically deforming the cushion) and securely anchor the cushion from falling out of place. 
         [0042]    Optionally an elastic cushion (e.g., a biocompatible elastomer, e.g., a soft resin or a rubber) can be inserted into the hollow portion, so that the elastomer can stop saliva from entering the hollow portion, as well as massage gum when biting and keep it healthier. 
         [0043]    The crown (tooth) portion can be further coated with porcelain or composite. 
         [0044]    The inventive device overcomes the disadvantages of both conventional RPD (poor mechanical strength and wear resistance of acrylic teeth, loss of occlusal vertical dimension, poor biting ability, etc.) and conventional crown and bridge (damages to its neighboring teeth to the missing teeth, etc.). 
         [0045]    The new housing design for the acrylic resin is for the easy withdrawal of the titanium casting framework. 
         [0046]    New tissue-side housing is for the relatively soft acrylic resin to provide the continuous stimulation of the lining mucosa which covers the post-extraction side. This stimulation will decrease the rate of alveolar bone resorption due to the loss of the teeth.