An ultrasound oral hygiene and therapeutic device comprises an array of ultrasonic transducers, a power generator, and a filling element. The ultrasonic transducer array, with optional radiation plates and reflection plates, produce uniform ultrasound radiation on each surface desirable to be treated by ultrasound radiation. The soft and resilient filling element snugly fits into a user's oral cavity, confines cleaning solution and the ultrasound action within a limited ultrasound action zone surrounding the surfaces desirable to be treated, and protects all other parts of the oral cavity from ultrasound radiation. The device provides superior, uniform, and consistent cleaning results in a short time. In particular, it cleans the entire dental surface, including the inter-dental and gingival areas. It is extremely easy to use, quiet, durable, energy efficient, and inexpensive in long run.