The hands-free dental appliance includes upper and lower tray members (12, 14) for receiving the teeth of the user, the tray members having teeth contact members such as bristles. A power assembly (28) moves the tray member in a reciprocal manner, resulting in cleaning of the surfaces of the teeth by the bristles. A grounding system (30) with bite portions (32, 34, 36) for biting contact whereby the user's teeth grounds the appliance to the user's mouth structure, reacting both static and dynamic forces, the grounding system being either separate from the tray members or flexibly connected to the tray members, allowing the tray members to move and clean the teeth without the user having to hold or otherwise manipulate the appliance.