The invention relates to a sensor (1) for fastening to a multi-bracket appliance for the upper jaw (2), to a multi-bracket appliance for the lower jaw (3), to an aligner for the upper jaw (2′；) and/or to an aligner for the lower jaw (3′；), in order to measure the time span during which a force is applied to a pressure, tension and/or shear-force sensor (11) of the sensor (1), whereby the wearing duration of orthodontic elastics (4) for multi-bracket appliances (2, 3) and/or aligners (2′；, 3′；) can be monitored, the sensor (1) being a sensor that is independent of the multi-bracket appliance (2, 3) and the brackets (23) and including a timer, a microcontroller having a data memory, and an elastic holder (16) and/or elastic guide (17). The invention further relates to a system (5) for monitoring the wearing duration of orthodontic elastics, including the sensor (1), a multi-bracket apparatus or an aligner for the upper jaw (2, 2′；) and the lower jaw (3, 3′；), an elastic (4) and an external reading device. The invention further relates to a method for monitoring the wearing duration of orthodontic elastics and to the use of the sensor (1) and of the system (5).
