Methods for direct fabrication of attachment placement appliances

#Prior orthodontic procedures typically involve repositioning a patient's teeth to a desired arrangement in order to correct malocclusions and/or improve aesthetics. To achieve these objectives, orthodontic appliances such as braces, retainers, shell aligners, and the like can be applied to the patient's teeth by an orthodontic practitioner. The appliance can be configured to exert force on one or more teeth in order to effect desired tooth movements. The application of force can be periodically adjusted by the practitioner (e.g., by altering the appliance or using different types of appliances) in order to incrementally reposition the teeth to a desired arrangement.

#Attachments can also be placed on teeth for dental and orthodontic treatments to aid in the repositioning of a patient's teeth.

#The prior orthodontic methods and apparatus to move teeth can be less than ideal in at least some respects. In some instances prior orthodontic approaches that employ an appliance with homogeneous and/or continuous material properties may not provide sufficient control over the forces applied to the teeth. For example, prior appliances fabricated from a single material may exhibit less than ideal control over the forces applied to subsets of teeth. In some instances, relatively stiff orthodontic appliances may require tighter manufacturing tolerances than would be ideal, and the manufacturing tolerances may undesirably affect the accuracy of the applied forces in at least some instances. Also, in at least some instances the appliance may distort at locations away from the teeth to be moved, such that the accuracy of the tooth movement can be less than ideal.

#The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:

#FIG. 1A illustrates a tooth repositioning appliance, in accordance with embodiments;

#FIG. 1B illustrates a tooth repositioning system, in accordance with embodiments;

#Systems, methods, and devices for improved orthodontic treatment of a patient's teeth are provided herein. In some embodiments, the present disclosure provides improved orthodontic appliances having different portions with different properties. The use of appliances with different localized properties as described herein can improve control over the application of forces and/or torques to different subsets of teeth, thus enhancing the predictability and effectiveness of orthodontic treatment. For example, an orthodontic appliance can include portions with different stiffness (e.g., a relatively stiff portion and a relatively compliant portion) to provide more consistent force and/or torque application even when manufacturing tolerances for the appliance are relatively poor. Additionally, the appliance design and fabrication methods described herein can enhance the accuracy and flexibility of producing appliances with different localized properties, thus allowing for the production of more complex and customized appliances.

#In one aspect, an orthodontic appliance for repositioning a patient's teeth in accordance with a treatment plan is provided. The appliance can comprise an outer shell comprising a plurality of cavities shaped to receive the patient's teeth and generate one or more of a force or a torque in response to the appliance being worn on the patient's teeth, and an inner structure having a stiffness different than a stiffness of the outer shell. The inner structure can be positioned on an inner surface of the outer shell in order to distribute the one or more of a force or a torque to at least one tooth received within the plurality of cavities.

#In another aspect, an orthodontic appliance for repositioning a patient's teeth in accordance with a treatment plan is provided. The appliance can comprise an outer shell comprising a plurality of teeth-receiving cavities shaped to exert one or more of a force or a torque on the patient's teeth, and an inner structure positioned on an inner surface of the outer shell. The inner structure can comprise a stiffness different than a stiffness of the outer shell such that the inner structure is configured to exhibit an amount of deformation greater than an amount of deformation exhibited by the outer shell.