Reinforced aligner hooks

Abstract

Orthodontic positioning devices, and related methods and systems, are disclosed for use with one or more orthodontic elastic members. The disclosed devices are configured to couple with an orthodontic elastic member so as to react a force from the elastic member into the appliance to, for example, generate traction forces on the patient's teeth to produce a desired occlusion. A positioning device includes a patient removable tooth positioning appliance having teeth receiving cavities shaped to receive and apply a resilient positioning force to a patient's teeth. The appliance includes a hook configured to interface with an orthodontic elastic member. The hook can be configured to be offset from a surface of a tooth when the appliance is coupled with the patient's teeth and no elastic member is coupled with the tooth. The hook can be curved so that the hook is more retentive on the aligner. The hook can be reinforced so that the reinforcement resists deformation when the elastic is in place.

1 . An orthodontic positioning device for use with an orthodontic elastic member, the device comprising:
 a patient removable orthodontic tooth positioning appliance having teeth receiving cavities shaped to receive and apply a resilient positioning force to a patient's teeth, the appliance comprising a hook configured to interface with an orthodontic elastic member so as to react a force from the elastic member into the patient-worn appliance, the hook configured to be laterally offset from a surface of a tooth when the appliance is coupled with the patient's teeth and no orthodontic elastic member is coupled with the hook.   
     
     
         2 . The device of  claim 1 , wherein the appliance comprises a reinforcement structure configured to stiffen the appliance against lateral deflection induced by the force from the elastic member. 
     
     
         3 . The device of  claim 2 , wherein the reinforcement structure comprises a corrugation in a portion of the appliance. 
     
     
         4 . The device of  claim 2 , wherein the appliance further comprises a locally reinforced area connected with the hook to stiffen the hook against lateral deflection induced by the force from the elastic member. 
     
     
         5 . The device of  claim 1 , wherein the appliance further comprises a locally reinforced area connected with the hook to stiffen the hook against deflection induced by the force from the elastic member. 
     
     
         6 . The device of  claim 1 , wherein the hook is gingivally offset from a gingival edge of the appliance. 
     
     
         7 . The device of  claim 1 , wherein an orthodontic elastic member contacts a surface of a tooth when the appliance is coupled with the patient's teeth and the orthodontic elastic member is coupled with the hook. 
     
     
         8 . The device of  claim 1 , wherein an orthodontic elastic member does not contact a surface of a tooth when the appliance is coupled with the patient's teeth and the orthodontic elastic member is coupled with the hook. 
     
     
         9 . The device of  claim 1 , whereby the tip of the hook angles or curves back toward a tooth surface such that a hook tip is pointed closer to the tooth than a body portion of the hook so as to avoid poking the patient's soft tissues. 
     
     
         10 . The device of  claim 1 , whereby the hook is curved, angled, or bent towards the gingival line so that the elastic can be secured onto the aligner without it falling off when the aligner has not yet been inserted. 
     
     
         11 . A method for using one or more orthodontic positioning devices, the method comprising:
 receiving a first orthodontic positioning device in accordance with  claim 1 ;   coupling the first positioning device with a first arch of a patient's teeth; and   coupling an orthodontic elastic member with the hook of the first positioning device to transfer a force from the elastic member into the first positioning device.   
     
     
         12 . The method of  claim 11 , further comprising:
 receiving a second orthodontic positioning device having teeth receiving cavities shaped to receive and apply a resilient positioning force to a patient's teeth, the second device comprising a hook configured to interface with an orthodontic elastic member so as to react a force from the elastic member into the patient-worn device, the hook configured to be offset from a surface of a tooth when the second device is coupled with the patient's teeth and no orthodontic elastic member is coupled with the hook;   coupling the second orthodontic positioning device with a second arch of the patient's teeth; and   coupling the orthodontic elastic member that is coupled with the hook of the first positioning device with the hook of the second positioning device.   
     
     
         13 . A computer-implemented method for designing an orthodontic positioning device having teeth receiving cavities, the method comprising:
 receiving a digital representation of a patient's teeth in a selected arrangement; and   modeling an appliance based on the received representation, the appliance comprising teeth receiving cavities shaped to receive and apply a resilient positioning force to the patient's teeth, the appliance comprising a hook configured to interface with an orthodontic elastic member so as to react a force from the elastic member into the patient-worn appliance, the hook configured to be offset from a surface of a tooth when the appliance is coupled with the patient's teeth and no orthodontic elastic member is coupled with the hook.   
     
     
         14 . The method of  claim 13 , wherein modeling an appliance comprises modeling a reinforcement structure configured to stiffen the appliance against lateral deflection induced by the force from the elastic member. 
     
     
         15 . The method of  claim 14 , wherein modeling a reinforcement structure comprises modeling a corrugation. 
     
     
         16 . The method of  claim 14 , wherein modeling a reinforcement structure comprises modeling a locally reinforced area connected with the hook to stiffen the hook against deflection induced by the force from the elastic member. 
     
     
         17 . A system for orthodontic repositioning of a patient's teeth, the system comprising:
 a plurality of orthodontic tooth positioning appliances for a patient's teeth, at least two of the appliances having different teeth receiving cavities shaped to receive and resiliently reposition the patient's teeth in a first arch of the patient's teeth from a first arrangement to a successive arrangement, at least one of the appliances comprising a hook configured to interface with an orthodontic elastic member so as to react a force from the elastic member into the patient-worn appliance, the hook configured to be offset from a surface of a tooth when the appliance is coupled with the patient's teeth in the first arch and no orthodontic elastic member is coupled with the hook.   
     
     
         18 . The system of  claim 17 , wherein the appliances comprise:
 a plurality of appliances for repositioning an upper arch of the patient's teeth; and   a plurality of appliances for repositioning a lower arch of the patient's teeth,   wherein one of the upper arch appliances and one of the lower arch appliances are configured to be worn simultaneously and coupled with each other via an orthodontic elastic member coupling the hook of the upper arch appliance to the hook of the lower arch appliance.   
     
     
         19 . The system of  claim 17 , wherein at least one of the appliances comprises a corrugation to stiffen the appliance against lateral deflection induced by the force from the elastic member. 
     
     
         20 . The system of  claim 17 , wherein at least one of the appliances comprises a locally reinforced area connected with the hook to stiffen the hook against deflection induced by the force from the elastic member. 
     
     
         21 . The system of  claim 17 , wherein the hook is disposed gingivally offset relative to a center of a tooth receiving cavity or a center of a clinical crown of a tooth as received in a cavity proximate to the hook. 
     
     
         22 . The system of  claim 17 , wherein the hook gingivally offset from a gingival line of the appliance. 
     
     
         23 . A method for manufacturing an orthodontic positioning appliance having teeth receiving cavities and an external hook for an orthodontic elastic member, the method comprising:
 receiving a digital representation of a patient's teeth in a selected arrangement;   defining a position and an orientation of an orthodontic elastic member relative to the digital representation;   modifying the digital representation to add a witness object adjacent to a tooth surface of the digital representation;   transmitting or storing the modified digital representation for delivery to a fabrication system for fabricating a mold corresponding to the modified digital representation and fabricating from the mold an orthodontic appliance comprising a hook configured to interface with an orthodontic elastic member so as to react a force from the elastic member into the patient-worn appliance.   
     
     
         24 . The method of  claim 23 , wherein the hook is configured to be laterally offset from a surface of a tooth or gingivally offset from a gingival edge of the appliance when the appliance is coupled with the patient's teeth and absent an orthodontic elastic member coupled with the hook. 
     
     
         25 . The method of  claim 23 , wherein fabricating the appliance comprises molding a sheet of elastomeric material over the mold. 
     
     
         26 . The method of  claim 23 , further comprising adding or removing material from the molded sheet. 
     
     
         27 . A method for manufacturing an orthodontic positioning appliance having teeth receiving cavities and an external hook for an orthodontic elastic member, the method comprising:
 receiving a digital representation of a patient's teeth in a selected arrangement;   defining a position and an orientation of an orthodontic elastic member relative to the digital representation;   modifying the digital representation to add a hook representation to the digital representation;   directly fabricating an positioning appliance from the modified digital representation, the appliance comprising a hook configured to interface with an orthodontic elastic member so as to react a force from the elastic member into the patient-worn appliance.   
     
     
         28 . The method of  claim 27 , wherein the device is fabricated using a rapid prototyping method.