My teeth are spying on me

In a short paper presented at the 17th annual international symposium on International symposium on wearable computers (alongside UbiComp’13) in Zurich, there was this interesting paper on a device that could potentially be made wireless and battery powered (prototype was neither) to detect compliance with a diet, smoking, drinking or to detect dental problems like teeth grinding.  There are articles about it in the Daily Mail and other popular media as well.  Privacy implications if your teeth spy on you?