The invention relates to a method for at least partly determining a movement pattern of a dental treatment means in particular a toothbrush said movement pattern resulting during a dental treatment in particular a teeth cleaning. The method has at least the following steps: moving the dental treatment means at least on an X/Y plane in order to treat surface portions of the teeth wherein data relating to at least one movement parameter in particular the movement direction or rotation the acceleration the path and/or the speed of the dental treatment means relative to a reference system which moves together with the head of the treated person is detected by means of an optical detection device； and providing the detected data to a processing device in order to determine the movement pattern.
