Systems for fabricating dental appliances are provided. In some embodiments, a system comprising one or more processors, and a memory operably coupled to the one or more processors and storing instructions that, when executed by the one or more processors, cause the system to determine an appliance geometry for a dental appliance including a shell configured to move the patient's teeth from an initial arrangement toward a target arrangement. The appliance geometry can include a first power arm having a first connection point for connecting to the shell, a second power arm having a second connection point for connecting to the shell or to a tooth, an elongate connecting structure coupled to the first and second power arms, and an elongate counter-force connector coupled to the first power arm and extending toward the second power arm.

Methods and systems for digitally designing a plurality of aligners are provided. In some embodiments, a method includes receiving an intraoral scan of the patient's teeth, and generating 3D dental model of the patient's teeth using the intraoral scan. The method can include identifying a movement path to move the patient's teeth from an initial arrangement toward a target arrangement through a plurality of intermediate arrangements in accordance with a treatment plan. The method can also include identifying one or more appliance features of at least one aligner, the one or more appliance features including one or more feature regions having one or more feature thicknesses. The method can further include instructing an additive manufacturing machine to directly fabricate the at least one aligner in a layer-by-layer fashion.

Systems, methods, and devices for improved orthodontic treatment of a patient's teeth are provided herein. A method may include determining a movement path to move one or more teeth from an initial arrangement to a target arrangement, determining an appliance geometry for an orthodontic appliance comprising a shell and one or more integrally formed components, wherein the shell comprises a plurality of teeth receiving cavities shaped to move the one or more teeth from the initial arrangement to the target arrangement, and generating instructions for direct fabrication of the orthodontic appliance, wherein the instructions are configured to cause direct fabrication of the shell using a first material and direct fabrication of the one or more integrally formed components using a second, different material.

Systems, methods, and devices for improved orthodontic treatment of a patient's teeth are provided herein. In some embodiments, a method includes determining an appliance geometry for a dental appliance. The appliance geometry can include a first region representing a shell comprising a plurality of teeth receiving cavities, and a second region representing at least one integrally formed component to be integrally joined to the shell. The method can also include generating instructions including a first digital representation of the shell based on the first region, and a second digital representation of the at least one integrally formed component based on the second region. The method can further include transmitting the instructions to a fabrication system configured to additively manufacture the dental appliance by fabricating the shell based on the first digital representation, concurrently with fabricating the at least one integrally formed component based on the second digital representation.

An orthodontic appliance may include an outer shell having 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. The orthodontic appliance may also include 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.

Methods for fabricating attachment placement appliances are provided. In some embodiments, a method includes directly fabricating an attachment placement appliance body including a support formed in a tooth-receiving cavity configured to receive a tooth. The method can include directly fabricating one or more coupling structures connected to the support, and directly fabricating an aligner attachment connected to the one or more coupling structures. The attachment placement appliance body can be configured to align the aligner attachment to a predetermined location on the tooth. The aligner attachment can be shaped to engage with an attachment well of a shell aligner and exert one or more forces on the tooth when the aligner attachment is coupled to the attachment well. The one or more coupling structures can be configured to release the aligner attachment with removal of the attachment placement appliance body from the tooth.

Systems, methods, and devices for producing orthodontic appliances are provided. In one aspect, an orthodontic appliance comprises 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. The orthodontic appliance can comprise 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.

Methods of planning dental treatments are provided. In some embodiments, a method includes determining a plurality of stages for incremental repositioning of a patient's teeth. The method can include determining, for at least one stage, a shape of a corresponding dental appliance body, and generating instructions for direct fabrication of the dental appliance body. The dental appliance body can include a support formed in a tooth-receiving cavity, one or more coupling structures formed proximate to the support, and an attachment formed proximate to the one or more coupling structures. The dental appliance body can be configured to align the attachment to a predetermined location on a tooth. The one or more coupling structures can be configured to release the attachment with removal of the dental appliance body from the tooth.

Methods of fabricating orthodontic appliances are provided. In some embodiments, a method includes determining an appliance geometry for an orthodontic appliance. The appliance geometry can include a plurality of power arms including a first power arm having a first connection point for connecting to a shell, and a second power arm having a second connection point for connecting to the shell or a tooth. The appliance geometry can also include an elongate connecting structure coupled to the first and second power arms, and an elongate counter-force connector coupled to the first power arm and extending toward the second power arm. The elongate connecting structure and the elongate counter-force connector can be coupled to the first power arm at respective locations separate from the first connection point. The elongate connecting structure can be coupled to the second power arm at a location separate from the second connection point.

Methods for designing orthodontic appliances for repositioning a patient's teeth are provided. In some embodiments, a method includes determining a movement path to move one or more teeth from an initial arrangement to a target arrangement, determining a force system to produce movement of the one or more teeth along the movement path, and determining an appliance geometry for an orthodontic appliance configured to produce the force system. The orthodontic appliance can include an outer shell comprising a plurality of teeth-receiving cavities and an inner structure positioned on an inner surface of the outer shell. The inner structure can have an elastic modulus different than an elastic modulus of the outer shell. The method can also include generating instructions for directly fabricating the orthodontic appliance using a layer-by-layer additive manufacturing technique.