HAP, available in Japan since 1970. wow, just found this where they compared HAP to fluoride and found no difference: https://www.nature.com/articles/s41405-01

HAP, available in Japan since 1970. wow, just found this where they compared HAP to fluoride and found no difference: https://www.nature.com/articles/s41405-019-0026-8 https://www.nature.com/articles/s41405-019-0026-8 I have novamin. I think it makes my teeth feel different. May be placebo. A lot of people swear by HAP, novamin, etc. I suspect it all comes down to increased oral care and diligence though!