Abstract: A new biofeedback modality for the treatment of bruxism. A mildly aversive, safe, liquid is inserted into, and sealed in, small, bilaterally-sleeved, polyethylene capsules. Two capsules are attached to a specially-constructed dental appliance which comfortably and securely places them between the lower and upper teeth. The appliance and capsules are worn at night or at other times when bruxism is suspected to occur. Whenever a sleeping or an awake patient attempts to brux, the capsules rupture and the liquid is released into the mouth. The liquid then draws the patient's conscious attention to, and forestalls, any attempt of teeth clenching or grinding. Variations of the method and device can be used to diagnose bruxism and to sustainably release medications and odor-masking substances into the mouth,.