Method for determining a movement or movement path of a dental treatment means occurring during a dental treatment, comprising the steps: moving the dental treatment means at least in an X-/Y- plane to treat surface portions of the teeth, wherein data relating to at least one movement parameter of the dental treatment means relative to a reference system, which moves with the head of the treated person, are captured by at least one optical capturing device, wherein the data represent characteristic points on the surface of the dental treatment means and/or lines on the surface of the dental treatment means and/or surface portions of the dental treatment means, - providing the captured data to a processor device to determine the movement or the movement path, wherein the processor device defines a further three-dimensional reference system that at least temporarily moves together with the dental treatment means in space during a movement of the dental treatment means, wherein the further reference system is formed from the characteristic points on the surface of the dental treatment means and/or the lines on the surface of the dental treatment means and/or the surface portions of the dental treatment means, wherein the characteristic points and/or lines and/or surfaces are formed by differing light and dark and/or differently-colored-designed portions of the dental treatment means, - providing sensor data from one or multiple sensor devices of a detection device, wherein the detection device is physically connected with the dental treatment means at least during the dental treatment, wherein the sensor device is a position-, speed-, acceleration- and/or rotation-sensor, - determining the movement or the movement path, wherein the data captured by the optical capturing device and the data captured by the detection device are used to determine the movement or movement path, wherein the position of the dental treatment means is determined by the optical capturing device and the movement or the movement path is determined from the position of the dental treatment means or from the positions of the dental treatment means and from the sensor data. moving the dental treatment means at least in an X-/Y- plane to treat surface portions of the teeth, wherein data relating to at least one movement parameter of the dental treatment means relative to a reference system, which moves with the head of the treated person, are captured by at least one optical capturing device, wherein the data represent characteristic points on the surface of the dental treatment means and/or lines on the surface of the dental treatment means and/or surface portions of the dental treatment means, - providing the captured data to a processor device to determine the movement or the movement path, wherein the processor device defines a further three-dimensional reference system that at least temporarily moves together with the dental treatment means in space during a movement of the dental treatment means, wherein the further reference system is formed from the characteristic points on the surface of the dental treatment means and/or the lines on the surface of the dental treatment means and/or the surface portions of the dental treatment means, wherein the characteristic points and/or lines and/or surfaces are formed by differing light and dark and/or differently-colored-designed portions of the dental treatment means, - providing sensor data from one or multiple sensor devices of a detection device, wherein the detection device is physically connected with the dental treatment means at least during the dental treatment, - providing the captured data to a processor device to determine the movement or the movement path, - providing sensor data from one or multiple sensor devices of a detection device, wherein the detection device is physically connected with the dental treatment means at least during the dental treatment, wherein the sensor device is a position-, speed-, acceleration- and/or rotation-sensor, - determining the movement or the movement path, wherein the data captured by the optical capturing device and the data captured by the detection device are used to determine the movement or movement path, wherein the position of the dental treatment means is determined by the optical capturing device and the movement or the movement path is determined from the position of the dental treatment means or from the positions of the dental treatment means and from the sensor data. - determining the movement or the movement path, wherein the data captured by the optical capturing device and the data captured by the detection device are used to determine the movement or movement path, wherein the position of the dental treatment means is determined by the optical capturing device and the movement or the movement path is determined from the position of the dental treatment means or from the positions of the dental treatment means and from the sensor data.