Determining a position of an oral care device

1. An oral care device comprising:

a head portion having a protuberance for engaging an interproximal region in a dental arch within an oral cavity;

at least one sensor for acquiring motion data for the oral care device; and

a processor configured to:

determine when the protuberance of the head portion engages an interproximal region in the oral cavity by detecting a pause in motion of the head portion along the dental arch; and

determine, based on motion data acquired by the at least one sensor as the protuberance moves between interproximal regions, a position of the head portion of the oral care device in the oral cavity.

2. An oral care device according to claim 1 , wherein the at least one sensor comprises at least one of an accelerometer, an orientation sensor and a proximity sensor.

3. An oral care device according to claim 1 , wherein the at least one sensor comprises an accelerometer, and wherein the processor is configured to:

integrate acceleration data from the accelerometer over time to obtain velocity data; and

determine when the protuberance engages an interproximal region by detecting a minimum in the velocity data.

4. An oral care device according to claim 3 , wherein the processor is configured to:

calculate a distance between interproximal regions by integrating the velocity data over time to obtain a distance moved by the protuberance between interproximal regions.

5. An oral care device according to claim 1 , wherein the at least one sensor comprises an orientation sensor for determining an orientation of the oral care device relative to the head of the user; and wherein the processor is configured to:

determine the position of the head portion of the oral care device based on the determined orientation.

6. An oral care device according to claim 1 , wherein the processor is configured to:

determine, from the motion data, a general path around a dental arch within the oral cavity; and

wherein the processor is configured to determine when the protuberance engages an interproximal region by detecting movement of the head portion in a direction substantially perpendicular to the general path.

7. An oral care device according to claim 1 , further comprising:

a detector for detecting an oral health disorder.

8. An oral care device according to claim 1 , wherein the oral care device comprises a toothbrush, the head portion of the toothbrush comprising a plurality of bristles;

wherein the protuberance comprises an extended tuft of bristles amongst the plurality of bristles.

9. An oral care device according to claim 1 , wherein the oral care device comprises an oral cleaning device configured to direct a flow of fluid from a nozzle of the head portion towards an interproximal region;

wherein the protuberance comprises the nozzle.

10. An oral care device comprising:

a head portion having a protuberance for engaging an interproximal region within an oral cavity;

at least one sensor for acquiring motion data for the oral care device; and

a processor configured to:

determine when the protuberance of the head portion engages an interproximal region in the oral cavity;

determine, based on motion data acquired by the at least one sensor as the protuberance moves between interproximal regions, a position of the head portion of the oral care device in the oral cavity; and

a user input mechanism;

wherein the processor is configured to determine that the protuberance of the head portion has engaged an interproximal region based on a user input received from the user input mechanism.

11. A method of determining a position of an oral care device along a dental arch in an oral cavity, the oral care device having a head portion which includes a protuberance for engaging an interproximal region within the oral cavity, and at least one sensor for acquiring motion data for the oral care device, the method comprising:

determining when the protuberance of the head portion engages an interproximal region in the oral cavity by detecting a pause in motion of the head portion along the dental arch; and

determining, based on motion data acquired by the at least one sensor as the protuberance moves between interproximal regions, a position of the head portion of the oral care device in the oral cavity.

12. A method according to claim 11 , further comprising:

applying a statistical model to the motion data prior to determining that the protuberance of the head portion has engaged an interproximal region.

13. A method of determining a position of an oral care device in an oral cavity, the oral care device having a head portion which includes a protuberance for engaging an interproximal region within the oral cavity, and at least one sensor for acquiring motion data for the oral care device, the method comprising:

determining when the protuberance of the head portion engages an interproximal region in the oral cavity;

determining, based on motion data acquired by the at least one sensor as the protuberance moves between interproximal regions, a position of the head portion of the oral care device in the oral cavity;

calculating a distance between interproximal regions;

comparing the calculated distance between interproximal regions with a previously-calculated distance between the same interproximal regions; and

generating an alert signal if it is determined that the compared distances differ by more than a threshold amount.

14. An oral care system comprising:

an oral care device including:

a head portion which includes a protuberance for engaging an interproximal region in a dental arch within an oral cavity; and

at least one sensor for acquiring motion data for the oral care device; and

processing circuitry configured to:

determine when the protuberance of the head portion engages an interproximal region in the oral cavity by detecting a pause in motion of the head portion along the dental arch; and

determine, based on motion data acquired by the at least one sensor as the protuberance moves between interproximal regions, a position of the head portion of the oral care device in the oral cavity.

15. An oral care system according to claim 14 , further comprising:

a motion detector for measuring movement of the head of the user relative to the oral care device;

wherein the processing circuitry is configured to calculate a distance between adjacent interproximal regions based at least in part on the measured movement.