An electric toothbrush that detects plaque on the teeth, ensures accurate plaque detection, and performs cleaning of plaque. The electric toothbrush may include a body having a gripping part and a stem with a brush unit detachably coupled to the body. The electric toothbrush may include a light emitting element for emitting light onto the tooth and a light receiving element for receiving light that reflects off of the tooth. A controller may be included to determine an amount of plaque on the tooth based on the amount of reflected light detected. The electric toothbrush may also include a fluid dispensing system that dispenses fluid based on the amount of reflected light detected. In some aspects, the electric toothbrush may operate in multiple oscillation modes, and it may only dispense fluid in some of the modes but not all of the modes.
