Smart Toothbrushes: Inertial Measurement Sensors Fusion with Visual Tracking

A proper toothbrushing is a crucial aspect to preserve person's dental health. Furthermore dierent brushing techniques have been dened for kids, adults and people with dierent dental appliances, prostheses, partial dentures or oral pathologies. In order to provide a real-time feedback to the user there are, mainly, two approaches: the first one is based on intelligent toothbrushes (called smart toothbrushes) where Inertial Measurement Units, bristles pressure sensor, and also cameras are placed on the toothbrush; data acquired is then transmitted and processed on a smartphone or tablet that monitor the user's habit and provide him/her with brushing statistics together with suggestions to tune brushing timing and technique. The second approach simplifies the toothbrush device transferring the computational eorts to the handheld device: from the onboard camera it has to track both user's face and toothbrush in order to extract brushing parameters. In this paper we compare the two approaches concluding that only a fusion of their data can produce an all-around exhaustive analysis of the tooth brushing technique.