I received a Neem powder based tooth powder from a friend and after trying it for a couple of days only I felt fresh, gums were happier and there was a sense of not putting chemicals in the mouth first thing in the morning. Traditionally people in India used to chew a twig from Neem tree to clean the teeth and mouth in general in the morning.
Neem tree grows almost across the country and grows pretty fast. Best option would be if people could go to the nearest tree and pick a twig and use it, but given our densely populated urban centers that can not have trees or not enough trees for the population. So I think there can be a business case for packaging these and making them available at retail stores.
This may be a good idea for organic products manufacturers, but the idea is so simple that it can be picked up by anyone. As idea exists in my mind today, it does not look like a high investment option, but this needs to be thought through.
Innovation would be required in packaging and them marketing it, getting people back to it to it.
Organic India and Neemfoundation gives more information about this native and medicinal tree.