A dissolving oral adhering disc (troche) with a dimple on at least one side to improve adhesion to hard convex surfaces in the mouth, including teeth, orthodontic braces, and gums (keratinized gingiva). The disc may be designed to prevent or treat a sore in the mouth opposite a tooth or brace and/or to release a medication into the mouth, to treat such as sore or to treat or prevent conditions elsewhere in the mouth or throat or stomach.