As a matter of fact, a recent study investigating TOTAL fluoride intake in children up to 4 years old and comparing fluoridated to non-fluoridated areas, found that TOTAL intake was actually higher in children in the non-fluoridated area.

"Overall, the total daily fluoride intake was highest, at 0.061 (0.027 - 0.127) mg/kg of body weight, in those children in the non-fluoridated area who used a fluoride toothpaste, while the children in the fluoridated area also using fluoride toothpaste consumed less fluoride, with a mean total daily fluoride intake of 0.048 (0.027 - 0.108) mg/kg of body weight."

Zohoori FV, Buzalaf MA, Cardoso CA, Olympio KP, Levy FM, Grizzo LT, Mangueira DF, Sampaio FC, Maguire A - "Total fluoride intake and excretion in children up to 4 years of age living in fluoridated and non-fluoridated areas" Eur J Oral Sci. 121(5):457-64 (2013)