Orthodontic appliances and related methods are provided, including a fast-dissolving and humidity-resistant coating, containing a colorant and a binder selected from a polyamide, cellulose derivative, or homopolymer/copolymer of poly(ethylene oxide). The coating can facilitate appliance identification and serve as a reference marking to assist the practitioner in appliance placement. Advantageously, the composition of these coatings allows the color marking to be rinsed off quickly, and yet the color of the coating does not bleed during storage even in high humidity environments. The fast-dissolving nature of these coatings also allows the coating to be deposited in concave and recessed areas of the appliance, such as the archwire slot and vertical slot, since these coatings can be removed prior to archwire installation.
