Abstract: Disposable prophy angles for use in combination with a reusable metal adapter on a contra-angle dental hand piece. The disposable prophy angles are assembled from three mass-produced components formed from plastic or other inexpensive material. Each disposable prophy angle is formed from a main body part having a nose portion and a barrel portion, a nose cap portion which with the nose portion forms an enclosed nose portion housing and an integral rotary part disposed in the enclosed nose portion housing which has a driven power input gear, bearing formations and a protruding prophy cup receiving button. Each reusable metal adapter has a shaft with gears mounted on opposite ends. One end of the adapter is inserted in the barrel portion with the gear on the inserted end in driving engagement with driven power input gear. The gear on the opposite end of the adapter is connected to the power output of a contra-angle dental hand piece.