A tray fitted to at least some teeth of a patient's upper or lower arch is provided for the application of medications to the teeth and to adjacent gum tissue for treatment of periodontal disease. The tray is constructed from resilient material molded to conform to the teeth and gum tissue. The tray includes at least one recess formed to conform to the teeth. A seal surrounds the recess at a location corresponding to the patient's gum line for applying pressure at the patient's gum line when the patient's teeth are disposed in the recess. The recess contains a quantity of a medication. Upon installation of the tray on the patient's teeth, the medication is forced onto the surface of the teeth and subgingivally by the seal into any pockets in the patient's gums proximate the teeth. If desired, a propulsion agent can be disposed within the recess such that upon application of the tray onto the patient's teeth, the propulsion agent generates pressure within the recess so as to positively force the medication onto the patient's teeth and into any of the pockets in the patient's gums proximate the teeth. Methods for making the tray and for applying medication to a patient's teeth and gums also are disclosed.