Abstract: 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.

Abstract: An apparatus for fabricating an optical fiber preform having a support for rotatably holding a reaction tube, a raw material supply unit for supplying a glass raw material from one end of the reaction tube to the interior of the reaction tube and a heater for heating the reaction tube by reciprocating in the axial direction of the reaction tube which comprises a pressure measuring unit at the other end of the reaction tube, a gas pressure control chamber having a gas inlet and an exhaust port, and a blower capable of controlling the introduced gas pressure according to the measured value of the pressure memasuring unit in the gas inlet. Thus, the apparatus can accurately control the internal pressure of a reaction tube in good responsiveness.