Use GC tooth Mousse which is a Japanese product and a well kept secret. My dentist suggested it as the only product with actual results on rebuilding enamel. Most Dentists in USA don't promote this keeping in mind their incentives and it's a 30 year old technology with great results.
Pubmed has loads of studies you can pursue.
It worked wonders for me.
https://www.amazon.com/TOOTH-MOUSSE-X40GM-DENTAL-PRODUCT/dp/...
There's a newer version called Mi paste which is distributed. https://www.gc.dental/america/products/operatory/preventive/...