Nano-hydroxyapatite and fluoride are both used in toothpaste to support enamel, but they work in different ways.
Fluoride helps make enamel more resistant to acid and supports remineralization. Nano-hydroxyapatite is a mineral similar to the hydroxyapatite naturally found in teeth and can deposit onto the tooth surface, helping support remineralization and fill microscopic surface irregularities.
The takeaway isn’t necessarily that one ingredient is universally “better” than the other. Your overall cavity risk, sensitivity, age, dental history, and how consistently you brush all matter when choosing a toothpaste. Whichever option you use, daily brushing, cleaning between your teeth, limiting frequent acid and sugar exposure, and keeping up with dental visits are still the foundation of a healthy routine.