Novamin is not available for sale in the US (though you can get it off ebay) and supposedly it is a toothpaste additive which can directly deposit onto teeth.
You can get products with the similar bioactive glass ingredient BioMin [1], though for whatever reason the version that also includes fluoride is not yet sold in the US.
[1] e.g. https://www.walgreens.com/store/c/dr.-collins-biomin-toothpa...