Abstract: Systems for moving teeth of a patient's dental arch from a first tooth arrangement to a second tooth arrangement include a plurality of resilient appliances such as positioning trays or elongated arch members that are used in sequence. Each appliance of the systems includes a row of spaced apart couplings for connection to respective teeth of the dental arch. The appliances have certain geometric characteristics that match the geometric characteristics of other appliances of the system, and at least one appliance has a stiffness that is greater than the stiffness of at least one other appliance.

Abstract: Articles including an orthodontic bracket having a base for bonding the bracket to a tooth are disclosed. A first part of an at least two-part adhesive is on the base of the bracket and a release substrate is in contact with the adhesive.

Abstract: An orthodontic appliance includes a latch that comprises at least one clip with a region for receiving an archwire. The clip also includes a recess for receiving a post of the appliance and for coupling the clip to remaining components of the appliance. The clip includes at least one protrusion that extends between the post-receiving recess and the archwire-receiving region, and the protrusion serves to retain the clip in place on the post.

Abstract: A mill blank assembly for a dental prosthesis includes a milling section and a support section for supporting the assembly in a milling machine. In certain embodiments, the milling section is adhesively bonded to the support section by a direct chemical bond that provides enhanced resistance to unintentional detachment of the milling section from the support section during a subsequent machining operation. Optionally, the support section includes a passageway that receives a quantity of flowable dental restorative material used to make the milling section, such that the restorative material that is located in the passageway provides additional resistance when hardened to unintentional detachment of the milling section from the support section.

Abstract: The relative orientation of an orthodontic appliance and a tooth is selected by providing a first relative orientation between the appliance and the tooth, and defining a first set of hypothetical reference lines or rays between the base of the appliance and the tooth in virtual three-dimensional space. The distance along each ray is then determined. Next, the relative orientation of the appliance and the tooth is changed to a second orientation. A second set of rays is defined between the appliance and the tooth, and the distance along each ray is determined. A mathematical computation is then carried out on the determined distances in order to help determine whether the first orientation or the second orientation provides a better fit between the base of the appliance and the tooth surface.

Abstract: An orthodontic appliance has a ceramic body and an archwire slot liner that is received in a channel of the body. The archwire slot liner has occlusal, gingival and lingual sections, and the lingual section is thicker than the occlusal or gingival section. The archwire slot liner helps resist fracture of the ceramic when the appliance is in use in the oral cavity, and yet need not adversely affect the aesthetic appearance of the appliance. A notch in the archwire slot liner is aligned with a channel in the body and provides a passageway for receiving a vertical auxiliary device.

Abstract: A quantity of a photocurable composition, such as an orthodontic adhesive containing a photoinitiator, is placed between the base of an orthodontic appliance and a replica of a patient's tooth structure. The replica is made using a material that transmits actinic radiation. As the appliance is pressed into firm contact with the replica tooth structure, an outer surface of the photocurable composition assumes the configuration of the underlying portion of the replica tooth structure. Actinic radiation is then directed to the photocurable composition, and at least part of the actinic radiation is directed through the replica tooth model in order to harden the photocurable composition. The hardened composition provides a contoured bonding surface having a shape that matches corresponding regions of the patient's tooth structure. Methods are also disclosed for making an orthodontic indirect bonding transfer apparatus for use with appliances having a contoured bonding surface.

Abstract: A trim cap for a sign cabinet such as a channel letter includes an elongated formable band along with a pressure activated adhesive layer that is connected to the band. The adhesive layer is conformable to facilitate adherence of the trim cap to the edge of a sign face of the light cabinet. Preferably, the adhesive layer comprises a pressure activated adhesive and a foam layer that includes a plurality of polymeric microspheres.

Abstract: Transfer apparatus is constructed for applying an orthodontic composition such as a bonding composition to selected areas of multiple teeth simultaneously. The selected areas of the teeth that receive the composition substantially correspond to areas of the teeth that subsequently receive orthodontic appliances. As a result, contact of the composition with other regions of the oral cavity such as the gingival tissue is avoided.

Abstract: Selection of orthodontic brackets from predefined and existing orthodontic brackets is provided by a user viewing a patient's teeth and using, for example, a user interface, to define a three-dimensional tooth/arch model from three-dimensional model data. Likewise, a prescription is selected. With such information, the teeth of the defined tooth/arch model can be positioned in prescribed positions. Once modifications to the prescription or for that matter the patient's tooth/arch model, if any, are made, predefined and existing orthodontic brackets can be selected, e.g., such selection can be based on selection criteria used to search a database including parameters defining such predefined and existing orthodontic brackets.

Abstract: An insert is removably received in a channel of an orthodontic appliance. The insert substantially prevents sections of the appliance from moving toward each other a distance that would otherwise be sufficient for debonding the appliance from the associated tooth. The insert may be used with the appliance alone, or in combination with the appliance and a positioning tray. The insert may also be advantageously employed during manufacture, shipping, patient set-up or other handling, and may also be used in the course of treatment. Additionally, the insert may be provided with structure for serving as a positioning jig.

Abstract: Inkjet printing apparatus for use with radiation curable ink includes a sensor for sensing the amount of radiation emitted by a source of radiation. A controller is connected to the sensor and is operable to vary the amount of radiation emitted by the radiation source in accordance with a signal received from the sensor. A drive mechanism moves the source of radiation to a location laterally offset from the substrate where the sensor is positioned.

Abstract: An orthodontic bracket has at least one tiewing and a groove behind the tiewing for receiving a ligature. The groove extends along a path that is inclined in a direction away from an archwire slot of the bracket as a central, upright reference plane bisecting the bracket is approached. In addition, the depth of the groove decreases as the reference plane is approached. Preferably, an outermost edge of at least one tiewing is inclined in a direction away from the archwire slot as the adjacent side of the bracket is approached. The tiewing is less likely to fracture during the course of orthodontic treatment, and yet the ease of ligation is not compromised.

Abstract: An orthodontic appliance includes a latch that comprises at least one clip with a region for receiving an archwire. The clip also includes a recess for receiving a post of the appliance, and the recess is not in communication with the archwire-receiving region. The post functions to secure the clip to remaining components of the appliance, such as a body or base of the appliance. Optionally, the clip may include a second recess for receiving a second post of the appliance.

Abstract: Methods of applying film to substrates are provided wherein the film matingly conforms to the configuration of the substrate, including areas adjacent protrusions or depressions in the substrate. In certain embodiments, the film is punctured by a probe and a vacuum is applied to the probe in order to aspirate air and urge the film toward a position of compliance with the substrate. Optionally, the film is softened by heat in order to facilitate conformance with the shape of the substrate.

Abstract: Apparatus for use in indirect bonding of orthodontic appliances includes a container having a chamber and a placement device received in the chamber. At least one orthodontic appliance is releasably connected to the placement device and has a base with a contour that is a replica of a portion of the patient's tooth structure. A bonding composition for bonding the appliance to the patient's tooth structure is applied to the base before the container is closed by the manufacturer, such that the practitioner can simply remove the placement device from the chamber and immediately transfer the appliances to the patient's teeth.

Abstract: The long axis of an object that is complex in shape, such as a tooth, may be accurately determined using digital data representing the shape of the object. A polyhedron is defined such that the center of the polyhedron coincides with a point representing the centroid of the object. Axis lines are then determined by establishing reference lines through each face of the polyhedron and the point representing the centroid of the object. The moment of the object is calculated about each axis line, and the axis line that corresponds to the smallest calculated moment is selected. Additional iterations of the method are then carried out by recursively subdividing the corresponding face into smaller sections until a desired angular accuracy is achieved. The method is particularly useful for orthodontic diagnosis and treatment.

Abstract: An indirect bonding apparatus is made by initially placing spacer material over a replica of the patient's tooth structure. A tray is then formed over the spacer material and hardened. Next, the spacer material is removed from the tooth replica and orthodontic appliances are placed on the replica at desired locations. A matrix material is placed between the tray and the replica and allowed to harden. Optionally, the apparatus includes features for facilitating removal of the transfer apparatus after the bonding procedure has been completed, and features for applying firm, uniform pressure to the appliances during the bonding procedure. Other aspects of indirect bonding are also described.

Abstract: An orthodontic appliance such as a bracket or buccal tube has a latch for retaining an archwire in an archwire slot. The latch releases the archwire from the archwire slot whenever the archwire exerts a force on the appliance that exceeds a certain minimum value. The latch comprises at least one clip having certain features that significantly reduce strain during opening movements of the clip, so that the likelihood of fracture of the clip during use is significantly reduced.

Abstract: A device for correcting the relative position of the jaws of an orthodontic patient includes a telescoping assembly along with a coil spring. As the patient's jaws are closed, the telescoping assembly exerts a force against the spring which tends to posture the jaws in correct occlusal relationship. The coil spring provides a yieldable force that avoids the need for a rigid, hard stop as the patient's jaws are closed.