Patent Publication Number: US-11045279-B2

Title: System and method for manufacturing crowns for teeth

Description:
This patent application is a Continuation-In-Part (CIP) patent application based on non-provisional patent application Ser. No. 15/902,719 filed Feb. 22, 2018, which is based on provisional patent application Ser. No. 62/477,214 filed Mar. 27, 2017 and provisional patent application Ser. No. 62/462,668 filed Feb. 23, 2017. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention is directed to a system and method for fabricating dental crowns and bridgework, and more particularly to a system and method that greatly reduces the time and simplifies the task of fabricating highly aesthetic dental crowns and bridgework that have excellent shape and anatomy and vital florescence. 
     Discussion of the Related Art 
     The fabrication of crowns and bridges has always been a time consuming and expensive process, requiring a considerable amount of skilled (artisan) labor to custom fit crowns and bridges for each case. Traditionally, a technician is required to prepare a pasty mixture of a ceramic powder and a liquid which gradually dries into a packed powder. While it is drying, the technician must mold and carve the pasty mixture into a shape resembling the natural tooth it is replacing, or in the case of an all ceramic crown, the technician must also match the contours of the tooth stump to which it is to be affixed. Not only is the shaping operation time consuming and difficult, but there is also the problem of the proper blending of colors in order to match the color of the teeth to each other or to those natural teeth adjacent to the one bring fabricated. In many instances, the resultant fabricated crown or bridge does not have a vital appearance and is easily discernible from the remaining teeth. 
     SUMMARY OF THE INVENTION 
     A system for fabricating dental crowns and bridgework uses a silicon composition or like soft and pliable material that is easily formed in less than ten minutes. The soft material is molded over real teeth or artificial teeth (either being referred to hereinafter as “model teeth” or “model tooth”) to create a crown mold and a bite mold. This provides the desired perfect anatomical shape. The soft mold is then placed within a prefabricated model of the patients teeth. Next, the upper and lower teeth of the model are pressed together so that the soft mold engages the opposing teeth of the model. This establishes the bite of the opposing teeth and perfect shape crown or bridgework. The prototype tooth (for a crown) or prototype teeth (for a bridge) is then removed from the soft mold and wet dental restoration material is placed in the mold. Next, the mold is vibrated to create the incisal in a thin layer to include the occlusal, buccal, lingual, and facial walls. At this stage, the molded incisal or shell can be removed from the mold for subsequent use. Alternatively, the incisal can remain in the soft mold and the body (i.e., more wet restoration material) is then added to the mold and vibrated using a variable speed vibration machine. Next, framework is pressed into the wet restoration material or other material forming the body until it reaches the established point or margin area. The mold is vibrated and moisture is removed from the wet restoration material. This can be done using a tissue. Once the restoration material is dry, the molded crown or bridgework is removed by opening the flexible mold and pushing the new teeth (i.e., crown or bridgework) out of the soft mold. Excess material is cut away along the lower margin area and restoration material can be added to the margin area as needed. The molded crown or bridgework is then baked in an oven for between 40 percent to 70 percent of the cure time. The crown/bridgework is then removed when partially cured so that the restoration material is still soft and easy to shape and carve to adjust the bite if needed for completion. In another embodiment of the invention, a block formation or overbuilt (exaggerated build-up) crown or bridgework (i.e., single unit or multiple unit) is molded using the soft mold, and is removed from the oven at 50%-80% of the cure time. Next, a CAD CAM system is used to allow precision cutting and formation by a milling machine so that no hand work is needed. In either embodiment, the crown/bridgework can be glazed back into the oven for completion. 
     OBJECTS AND ADVANTAGES OF THE INVENTION 
     Considering the forgoing, it is a primary object of the present invention to provide a system for producing dental crowns and bridges that eliminates between fifty percent and eighty percent of the labor normally involved in the currently used processes of producing dental crowns and bridges. 
     It is a further object of the present invention to provide a system for producing dental crowns and bridges that produces perfectly shaped and anatomically correct crowns and bridges to provide an extremely natural appearance. 
     It is a further object of the present invention to provide a system for producing dental crowns and bridges of the desired aesthetically vital color that match the shade guide. 
     It is a further object of the present invention to provide a system for producing dental crowns and bridges with high quality control. 
     It is a further object of the present invention to provide a system for producing dental crowns and bridges that are vital fluorescent. 
     It is a further object of the present invention to provide a system for producing dental crowns and bridges having high end aesthetics. 
     It is a further object of the present invention to provide a system for producing dental crowns and bridges that allows an average dental ceramist to create dental crowns and bridges that are on the level of a highly skilled artisan in the field of dental prosthetics in less than half the time normally required by a skilled artisan to create dental crowns and bridges using existing techniques, materials, machinery and systems. 
     It is a further object of the present invention to provide a system for producing dental crowns and bridges which eliminates the need for grinding and buildup, as well as unnecessary waste of materials (e.g., porcelain). 
     It is a further object of the present invention to provide a system for producing dental crowns and bridges which eliminates the need for multiple bakes in a porcelain oven. 
     It is a further object of the present invention to provide a system for producing dental crowns and bridges which eliminates the need to carve the anatomy into the crown or bridgework with a high speed air turbine or brush. 
     It is a further object of the present invention to provide a system for producing dental crowns and bridges which creates perfect anatomically correct buccal, lingual and facial walls that are extremely vital and natural in appearance. 
     It is a further object of the present invention to provide a system for producing dental crowns and bridges that saves fifty percent to eighty percent of time compared to existing techniques and systems in the related art. 
     It is a further object of the present invention to provide a system for producing dental crowns and bridges which can be used to create a single unit (i.e., crown for one tooth) or multiple units, as well as a full mouth rehabilitation including upper and lower bridgework. 
     It is a further object of the present invention to provide a system for producing dental crowns and bridges wherein the incisal can be pressed by the oven a first time and a body of the crown can be pressed during a second time or process for individual blending of different incisals and colors. 
     It is a further object of the present invention to provide a system for producing dental crowns and bridges that can be used with any moldable dental restoration material. 
     It is a further object of the present invention to provide a system for producing dental crowns and bridges that can be used with metal crowns and bridges or ceramic crowns and bridges. 
     It is a further object of the present invention to provide a system for producing dental crowns and bridges that can be used on zirconia coping while being very vital and aesthetically pleasing. 
     It is a further object of the present invention to provide a system for producing dental crowns and bridges wherein a block formation or overbuilt (i.e., exaggerated size) tooth formation is molded in a soft mold and then 60%-80% cured at which time the final crown or bridgework is cut by a milling machine with the use of a CAD CAM system. 
     It is a further object of the present invention to provide a system for producing dental crowns and bridges that separates interproximal area on bridgework and rounds off teeth perfectly which saves a significant amount of bench time and eliminates the need for multiple bakes in an oven. 
     These and other objects and advantages of the present invention are more readily apparent with reference to the following detailed description. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention is directed to a system and method for fabricating dental crowns and bridgework using various dental restoration materials such as, but not limited to porcelain or zirconia. To begin, real teeth or artificial teeth (i.e., “model teeth”) are selected for a particular patient that will be fitted with the fabricated crown or bridgework. The model tooth or teeth are selected to match the anatomy of the patient and should be slightly larger to allow for shrinking of the dental restoration material during fabrication of the crown or bridgework. Next, a silicon composition or like soft and pliable material is molded over the model teeth to establish a crown and bite mold that provides the desired perfect anatomical shape. The soft mold is then placed within a prefabricated model of the patient&#39;s teeth that has upper and lower teeth replicating the patient&#39;s upper and lower teeth. Next, the upper and lower teeth of the model are pressed together to establish the bite of the opposing teeth and perfect shape crown or bridgework. The model tooth (or teeth) is then removed from the soft mold and a layer of wet dental restoration material (e.g., porcelain or zirconia) is applied to the inner walls of the mold where the prototype tooth was removed (i.e., the mold cavity). Next, the mold is vibrated to create the incisal in a thin layer to include the occlusal, buccal, lingual, and facial walls. Next, more restoration material for the body is added to the mold and vibrated using a variable speed vibration machine. The framework is then pressed into the wet restoration material forming the body until it reaches the established point or margin area. The framework is prefabricated to be congruent with the shape of the patient&#39;s tooth stump to which the crown or bridge is to be affixed. The mold is vibrated and moisture is removed from the wet restoration material using a tissue or other method. Once the restoration material is dry, the molded crown or bridgework is removed from the mold by opening the flexible mold and pushing the new teeth (i.e., crown or bridgework) out of the soft mold and into a tissue. Excess material is cut away along the lower margin area and restoration material can be added to the margin area as needed. The molded crown is then baked in an oven for between forty percent and seventy percent of the cure time. The crown/bridgework is then removed when partially cured so that the restoration material is still soft and easy to shape and carve to adjust the bite if needed for completion. In another embodiment of the invention, a block formation or overbuilt (exaggerated build-up) crown or bridgework (i.e., single unit or multiple unit) is molded using the soft mold, and is removed from the oven at 50%-80% of the cure time. Next, a CAD CAM system is used to allow precision cutting and formation by a milling machine so that no hand work is needed. In either embodiment, the crown/bridgework can be glazed back into the oven for completion. 
     While the present invention has been shown and described in accordance with a preferred and practical embodiment, it is recognized that departures from the instant disclosure are fully contemplated within the spirit and scope of the present invention which is not to be limited, except as defined in the following claims as interpreted under the Doctrine of Equivalents.