“ We have unusually strong marketing connections; Vitalik approves of us; Aella is a marketing advisor on this project; SlateStarCodex is well aware of us. We are quite networked in the Effective Altruism space. We could plausibly get an Elon tweet. ”
From the short investor spiel document. Also they want to just bypass the FDA?
Buried in the google drive is a note that this does not remove the need for brushing teeth, but it just notes that not doing that will give you bad breath.
In fact I believe that this is the true cause of this not being a product - people will still need to brush their teeth for other reasons than preventing cavities. If brushing teeth correctly currently lessens the risk of both caries and periodontal disease, having a shot that removes the risk of caries could conceivably mean less conscientious tooth care, which increases the risk of gum problems.