Rapid prototyped transfer tray for orthodontic appliances

Abstract

The present invention is directed to computer-implemented methods of making a transfer tray using rapid prototyping techniques, where the gingival edge of the tray is defined to intersect with at least one receptacle for receiving an orthodontic appliance. This tray configuration helps to minimize the travel distance of the tray when placing the tray over a patient's teeth, while also preserving a high degree of mechanical retention for retaining the appliance until such time that the appliance is bonded to the tooth. Other aspects of the tray and associated methods of bonding are directed to a frangible web that extends over the gingival portion of the receptacle and fractures to facilitate tray removal after bonding.

1 . A method of creating a transfer tray model, the method comprising:
 obtaining a virtual model of a patient's dental structure and locations for a plurality of virtual orthodontic appliances on the model;   providing a virtual receptacle at each appliance location, wherein each virtual receptacle has a configuration that matches at least a portion of one of the appliances; and   deriving a virtual tray body extending across at least a portion of the model and at least a portion of each receptacle remote from the model, wherein the act of deriving a virtual tray body includes the act of defining an gingival edge of the tray body that intersects each virtual receptacle so that, when an appliance is retained in each receptacle, all facially oriented surfaces of the appliance located in an occlusal direction from the gingival edge are enclosed by a portion of the tray body extending continuously across the receptacle and all facially oriented surfaces of the appliance located in a gingival direction from the gingival edge are exposed.   
     
     
         2 . The method of  claim 1  and further comprising forming the transfer tray, wherein the transfer tray includes a physical tray body and physical receptacles that correspond to the virtual tray body and virtual receptacles respectively. 
     
     
         3 . The method of  claim 2 , wherein the transfer tray is formed by rapid prototyping. 
     
     
         4 . The method of  claim 1 , wherein the act of defining a gingival edge comprises trimming the virtual tray body by creating a cutting surface that intersects each receptacle and virtually removing the portion of the tray body that is located in the gingival direction from the cutting surface. 
     
     
         5 . The method of  claim 1 , wherein the step of obtaining a virtual model of a patient's dental structure and locations for a plurality of virtual orthodontic appliance on the model comprises determining a desired location for the virtual orthodontic appliances on the model. 
     
     
         6 . The method of  claim 1 , further comprising rendering a virtual stop member that connects to the tray body and matches at least a portion of the virtual model. 
     
     
         7 . The method of  claim 6 , wherein the virtual stop member includes a posterior section that matches a portion of a molar tooth and an anterior section that matches a portion of an anterior tooth. 
     
     
         8 . The method of  claim 6 , and further comprising forming the transfer tray, wherein the transfer tray includes a physical tray body and physical receptacles that correspond to the virtual tray body and virtual receptacles respectively, and wherein the transfer tray further includes a physical stop member that corresponds to the virtual stop member and wherein the physical tray body has a first Shore hardness and the physical stop member has a second Shore hardness that is greater than the first Shore hardness. 
     
     
         9 . The method of  claim 1 , further comprising placing an orthodontic appliance in one of the physical receptacles. 
     
     
         10 . A method of making a transfer tray for bonding an orthodontic appliance comprising:
 obtaining a virtual model of a patient's dental structure and a plurality of virtual orthodontic appliances on the model;   creating a virtual tray body extending across at least a portion of the model, the virtual tray body including, for each virtual appliance, a virtual receptacle having a configuration that matches at least a portion of the corresponding virtual appliance, wherein the tray body extends continuously across at least a portion of each virtual receptacle remote from the model,   wherein the act of creating a virtual tray body includes the act of defining a gingival edge of the tray body that intersects each virtual receptacle; and   forming the transfer tray by rapid prototyping, wherein the transfer tray includes a physical tray body and one or more a physical receptacles that correspond to the virtual tray body and virtual receptacles respectively, each physical receptacle sufficient to releasably retain a physical orthodontic appliance corresponding to the virtual appliance,   whereby when a physical appliance is retained in a corresponding physical receptacle, such appliance will include first facially oriented surface that extend below the gingival edge of the tray body and second facially oriented surfaces of the appliance that extend an occlusal direction from the gingival edge of the tray body, wherein all the second surfaces are enclosed by the portion of the tray body extending continuously across the physical receptacle and the first surfaces are not enclosed by any portion of the tray body.   
     
     
         11 . The method of  claim 10 , wherein the physical receptacle is open-ended in a generally gingival direction to facilitate occlusal detachment of the transfer tray from the corresponding physical orthodontic appliance. 
     
     
         12 . The method of  claim 10 , wherein the act of creating a virtual tray body includes the steps of providing a virtual receptacle at each appliance location, wherein each virtual receptacle has a configuration that matches at least a portion of one of the appliances; and
 deriving a virtual tray body extending across at least a portion of the model and at least a portion of each receptacle remote from the model.   
     
     
         13 . The method of  claim 10 , wherein the act of defining a gingival edge comprises trimming the virtual tray body by creating a cutting surface that intersects each receptacle and virtually removing the portion of the tray body that is located in the gingival direction from the cutting surface. 
     
     
         14 . The method of  claim 10 , wherein the step of obtaining a virtual model of a patient's dental structure and locations for a plurality of virtual orthodontic appliance on the model comprises determining a desired location for the virtual orthodontic appliances on the model.