Ultrasonic toothbrushes employing an acoustic waveguide

A toothbrush comprising:

• a toothbrush head having an acoustic waveguide and at least one bristle tuft comprising a plurality of bristles projecting from a support structure;
• an ultrasound transducer mounted in the toothbrush head and acoustically coupled to the acoustic waveguide that operates, during an operating cycle, to produce ultrasonic energy at frequencies of less than 1.0 MHz;
• a motor mounted in a handle that operates, during an operating cycle, to vibrate tips of the bristles;
• a power source mounted in the handle;
• and
• a transformer assembly that inductively couples and transfers power from the power source to the ultrasound transducer.

A toothbrush having:

• a toothbrush head comprising an ultrasound transducer assembly, an acoustic waveguide and at least one bristle tuft comprising a plurality of bristles projecting from a support structure, wherein:
• the ultrasound transducer assembly comprises at least two piezoelectric elements arranged mechanically in series with each piezoelectric element being electrically connected to another piezoelectric element in parallel;
• the ultrasound transducer assembly is acoustically coupled to the acoustic waveguide;
• the ultrasound transducer assembly operates to produce ultrasonic energy at frequencies of less than 1.0 MHz during an operating cycle;
• and the acoustic waveguide is provided as a unitary structure having a generally block-like, three-dimensional configuration and having multiple faces;
• and
• a motor mounted in a handle that is mechanically coupled to the support structure during an operating cycle to oscillate the bristles.