A portable dental prophylaxis and bleaching system is provided for simultaneous tooth polishing and bleaching. It includes an oscillatory driving handpiece, a dental angle with a disposable rubber cup assembly, a dual-component dispenser, and a disposable mouthpiece. The battery-powered handpiece transforms a continuous rotation through a driving cam into a rotary oscillation which is then transferred through the attached dental angle to the rubber cup with an obtuse angle at its distal output end. The dispenser is operated manually to correctly apportion and mix the dual treatment materials into the rubber cup. In order to provide longer shelf life and effective bleaching action, the treatment materials are maintained at optimal pH values in separate compartments within the dispenser before use. The disposable mouthpiece is shaped for easy access to the users teeth while protecting the gum surfaces. The system can be used both in dental clinics and at home.