An oral cleaning system comprising: an oral cleaning device comprising: a body portion; a brush head member extending from the body portion, wherein at least a portion of the brush head member is configured to move relative to the body portion; and an optical sensor positioned relative to the brush head member and body portion, wherein the optical sensor is configured to obtain optical sensor data resulting from a deflection or rotation of the brush head member relative to the body portion; wherein the optical sensor comprises: a first portion positioned on the body portion and comprising either a light source, a first light sensor positioned on one side of the light source, and a second light sensor positioned on a second side of the light source, or a light sensor, a first light source positioned on one side of the light sensor, and a second light source positioned on a second side of the light sensor; and a second portion positioned on the brush head member or on a transmission component for transmitting movements generated by a drivetrain in the body portion to the brush head member, the second portion comprising a reflector; and a controller configured to receive the optical sensor data and determine the deflection or rotation of the brush head member relative to the body portion. an oral cleaning device comprising: a body portion; a brush head member extending from the body portion, wherein at least a portion of the brush head member is configured to move relative to the body portion; and an optical sensor positioned relative to the brush head member and body portion, wherein the optical sensor is configured to obtain optical sensor data resulting from a deflection or rotation of the brush head member relative to the body portion; wherein the optical sensor comprises: a first portion positioned on the body portion and comprising either a light source, a first light sensor positioned on one side of the light source, and a second light sensor positioned on a second side of the light source, or a light sensor, a first light source positioned on one side of the light sensor, and a second light source positioned on a second side of the light sensor; and a second portion positioned on the brush head member or on a transmission component for transmitting movements generated by a drivetrain in the body portion to the brush head member, the second portion comprising a reflector; and a body portion; a brush head member extending from the body portion, wherein at least a portion of the brush head member is configured to move relative to the body portion; and an optical sensor positioned relative to the brush head member and body portion, wherein the optical sensor is configured to obtain optical sensor data resulting from a deflection or rotation of the brush head member relative to the body portion; wherein the optical sensor comprises: a first portion positioned on the body portion and comprising either a light source, a first light sensor positioned on one side of the light source, and a second light sensor positioned on a second side of the light source, or a light sensor, a first light source positioned on one side of the light sensor, and a second light source positioned on a second side of the light sensor; and a second portion positioned on the brush head member or on a transmission component for transmitting movements generated by a drivetrain in the body portion to the brush head member, the second portion comprising a reflector; and a first portion positioned on the body portion and comprising either a light source, a first light sensor positioned on one side of the light source, and a second light sensor positioned on a second side of the light source, or a light sensor, a first light source positioned on one side of the light sensor, and a second light source positioned on a second side of the light sensor; and either a light source, a first light sensor positioned on one side of the light source, and a second light sensor positioned on a second side of the light source, or a light sensor, a first light source positioned on one side of the light sensor, and a second light source positioned on a second side of the light sensor; and a second portion positioned on the brush head member or on a transmission component for transmitting movements generated by a drivetrain in the body portion to the brush head member, the second portion comprising a reflector; and a controller configured to receive the optical sensor data and determine the deflection or rotation of the brush head member relative to the body portion.