A method includes selecting a treatment mode displayed on a screen of a mobile phone or tablet PC, using a camera of the tablet PC or mobile phone to capture an image area containing (i) one or both pupils, the nose, eyebrows, eye hole, lips, ears, cheeks and/or chin of the person, and (ii) a toothbrush moving at least in an X-/Y-plane, and wirelessly receiving sensor data from the toothbrush in the mobile phone or tablet PC. The sensor data contains at least rotational movements and/or acceleration of the toothbrush captured by an acceleration sensor and/or a rotation sensor, disposed in or on the toothbrush. Thereafter, the method includes processing the sensor data in a processor, thereby generating processed sensor data, generating correction information based on the processed sensor data and the selected treatment mode, and displaying the correction information on the screen of the mobile phone or tablet PC.
