Orthodontic appliances and materials

A method for forming an orthodontic appliance to have a color and gloss resembling natural teeth, the method comprising:

• placing a laminate material into an orthodontic appliance thermoforming device, wherein, before thermoforming, the laminate material comprises:
• a first layer comprising a first thermoplastic material having a transparent appearance;
• a second layer comprising a second thermoplastic material, the second thermoplastic material having a non-transparent appearance;
• and
• a third layer comprising the first thermoplastic material, wherein the second layer is between the first and third layer;
• determining a target degree of translucence of the orthodontic appliance to resemble a color and gloss of natural teeth;
• selecting thicknesses of the first, second, and third layers;
• thermoforming the laminate material into the orthodontic appliance according to pressure, heating, and time settings of the orthodontic appliance thermoforming device,
• wherein the thicknesses of the first, second, and third layers, as well as at least the heating and time settings, are selected to tune translucence of the orthodontic appliance to the target degree of translucence to resemble a color and gloss of natural teeth,
• wherein the thicknesses of the first, second, and third layers are selected to mitigate gloss to resemble the gloss of natural teeth,
• wherein the first thermoplastic material of the first and third layers is a transparent copolyester and the second thermoplastic material of the second layer is a thermoplastic copolyester that is opaque prior to thermoforming,
• wherein the thermoforming causes the second thermoplastic material to increase in relative decrystallization with increased heating time and thereby increase relative translucency and relative transparency of the second layer;
• and
• wherein the heating and time settings are selected to tune a translucence appearance of the second layer by increasing the relative decrystallization of the second layer such that the second thermoplastic material of the orthodontic appliance transitions during thermoforming from the non-transparent appearance to a translucent appearance that provides the target degree of translucence to resemble a color and gloss of natural teeth.