It seems to me the two are effectively the same unless you have significantly misshaped teeth (remineralizing vs regenerating). I also use hydroxyapatite, just to reduce my fluoride exposure, although I believe fluoride is supposed to be a more potent remineralizer (and fluorapatite is allegedly stronger than natural hydroxyapatite). But the upside is that I don't mind swishing hydroxyapatite around in my mouth for 10 minutes, twice a day, so whenever I go to the dentist, I'm the healthiest mouth of the day (not the case pre-hydroxyapatite tooth paste/powder).
NHAP particles are smaller than fluoride particles, so they're able to penetrate farther into the porous surface of the teeth; flouride basically can only coat the surface. There is some research indicating that NHAP is more effective than flouride at remineralizing (e.g. https://pmc.ncbi.nlm.nih.gov/articles/PMC4252862/) but that flouride is more protective than NHAP because NHAP isn't protective at all. (The flouride creates a temporary sacrificial enamel-like shell layer that closes off pores in the surface of the teeth in addition to buffering acids; the NHAP will just create new enamel.)
My dentist says that NHAP is great if you have lots of cavities or drink lots of acidic drinks like soda, but once your enamel is repaired too much of NHAP can actually cause weird growths.
Dave's toothpaste has both NHAP and flouride (and the sensitivity agent used in Sensyodyne) if you're looking for the best of all worlds in the U.S.
After doing some research, I decided to go for this one: https://drjennatural.com/products/dr-jen-super-paste-with-na.... 10% nHAP (rod-shaped), RDA under 50 (exact number unspecified), nothing obviously objectionable in the ingredients, and comes with or without fluoride. My only minor quibble is that I couldn't determine the exact range of HAP particle sizes, which some other vendors do list. On the other hand, it has some strong reviews that seem credible, and there aren't many other options that explicitly provide 10% nHAP with a low RDA, and even fewer that offer a fluoridated version on top of that.
SuperMouth also looked like a great option with an RDA of 67 (particularly for kids who like crazy flavors), and Elims also looked good for anyone who doesn't mind the 92.71 RDA. Ollie stood out for its minimal ingredients list, but turned out to have a relatively high RDA of 143.
I currently use BioMin C in the morning and F at night, but based on everything I'm learning right now about nHAP, I figure it can't hurt to stack Dr. Jen with those. Maybe in a few years I'll get some keratin in the mix too.
Nobs is good because they only use rod-shaped NHA, not needle-shaped NHA which has a worse safety profile. Safety profile is important for anything nano
IDK how to tell what brand uses what type without independent testing or taking their word for it. Several makers have come out and said needle-shaped is cheaper to buy so if a brand has 10% formulation as opposed to 1 or 3 or 5%, it is more likely to be using needle-shaped. (And there is a separate conversation to be had whether 10% is needed/ideal concentration anyway)
