A tooth brushing monitoring device for use with a toothbrush during tooth brushing, which monitoring device comprises: an input device for taking user inputs, an acceleration sensor for producing signals during tooth brushing, a signal conditioner receiving and processing signals from the acceleration sensor, which signal conditioner, while said toothbrush and monitoring device is used for brushing a predetermined or user indicated teeth region (R-U, L-U, R-D, L-D) comprising a plurality of predefined teeth surfaces (1 - 12), identifies a brushing cycle based on a specific acceleration of a brush head of said toothbrush in a longitudinal direction of said brush head, and in response to an identified brushing cycle, said signal conditioner identifies the predefined teeth surface (1 - 12) that was brushed with the identified brushing cycle based on the inclination of the monitoring device in the earth's gravity field during the brushing cycle, a comparator, and an output device for indicating that the brushing of a teeth region (L - U) has been accepted, characterized in that the monitoring device comprises a memory for maintaining at least one teeth surface specific reference value for each predefined teeth surface (2, 6, 10) of each teeth region (L - U), the signal conditioner registers the identified brushing cycle of the identified teeth surface (1 - 12) with a corresponding teeth surface specific counter, the comparator compares the numbers of brushing cycles registered by each of the teeth surface (2, 6, 10) specific counters during brushing of a teeth region with the corresponding teeth surface (2, 6, 10) specific reference values maintained in said memory, and the output device indicates that the brushing of the teeth region (L - U) in question has been accepted, if the comparator indicates that the number of brushing cycles registered by each teeth surface (2, 6, 10) specific counter during the brushing of the teeth region (L - U) in question corresponds with a predefined accuracy with the corresponding reference values for the teeth region (L - U) in question. an input device for taking user inputs, an acceleration sensor for producing signals during tooth brushing, a signal conditioner receiving and processing signals from the acceleration sensor, which signal conditioner, while said toothbrush and monitoring device is used for brushing a predetermined or user indicated teeth region (R-U, L-U, R-D, L-D) comprising a plurality of predefined teeth surfaces (1 - 12), identifies a brushing cycle based on a specific acceleration of a brush head of said toothbrush in a longitudinal direction of said brush head, and in response to an identified brushing cycle, said signal conditioner identifies the predefined teeth surface (1 - 12) that was brushed with the identified brushing cycle based on the inclination of the monitoring device in the earth's gravity field during the brushing cycle, a comparator, and an output device for indicating that the brushing of a teeth region (L - U) has been accepted, characterized in that the monitoring device comprises a memory for maintaining at least one teeth surface specific reference value for each predefined teeth surface (2, 6, 10) of each teeth region (L - U), the signal conditioner registers the identified brushing cycle of the identified teeth surface (1 - 12) with a corresponding teeth surface specific counter, the comparator compares the numbers of brushing cycles registered by each of the teeth surface (2, 6, 10) specific counters during brushing of a teeth region with the corresponding teeth surface (2, 6, 10) specific reference values maintained in said memory, and the output device indicates that the brushing of the teeth region (L - U) in question has been accepted, if the comparator indicates that the number of brushing cycles registered by each teeth surface (2, 6, 10) specific counter during the brushing of the teeth region (L - U) in question corresponds with a predefined accuracy with the corresponding reference values for the teeth region (L - U) in question.