I have found Dentacoin platform with the native token of the same name accidentaly when I was looking for a new dentist. From the first sight it was very cool platform which rewards you with free tokens for making reviews and passing their survey (somtimes there are double prizes). You can earn quite a reasonable amount. They are also making promotions and also educating about oral hygiene and health. I feel that the informations are the most valuable part of the project. On the other hand I was disappointed with their customer center which do not respond (and if so without any relevant asnwer). The bad feature is how they apply ther ban policy which is not clear and works badly and threating new user for better adoption.