Excerpt from:

White Paper on Fluoride Toothpaste
By the Association of State and Territorial Dental Directors (ASTDD)
Adopted January 19, 2016

Concluding Statement:

ASTDD supports twice daily use of toothpaste containing 1000-1500 ppm fluoride, in fluoridated and non-fluoridated communities, for the prevention of tooth decay beginning with the eruption of the first tooth and throughout life.

See original paper