Texas Attorney General Ken Paxton (R) announced investigations Thursday of leading toothpaste companies, accusing them of misusing fluoride in their products.

“I will use every tool available to protect our kids from dangerous levels of fluoride exposure and deceptive advertising,” Paxton, who is also a Senate candidate, said in a statement.

The investigation announced three weeks after Paxton declared his campaign to primary Sen. John Cornyn (R) in next year’s midterm elections marks an expansion of the culture war over fluoride from drinking water into toothpaste.

Fluoride is an element that strengthens tooth enamel, in part by bonding with phosphate and calcium in teeth to fight the process that causes cavities to form and its addition to drinking water and toothpaste has slashed tooth decay in the U.S.

That’s why most mainline physicians group including the American Academy of Pediatrics or the American Dental Association support fluoridation of toothpaste and drinking water.

Research from the 1990s suggests that fluoride in water cuts cavities by up to 25 percent in children; mid-20th century studies found reductions of up to 70 percent.

But at high enough doses meaning much higher than the amount in U.S. drinking water or properly used toothpaste some federal findings suggest that fluoride can lower IQ in children.

Removal of fluoride from drinking water is a principle goal of a movement whose most famous member is Health and Human Services (HHS) Secretary Robert F. Kennedy Jr. that sees fluoridation as dangerous and unnecessary. 

In March, Utah became the first state to prohibit fluoride in drinking water a ban something polling suggests 80 percent of the state electorate opposes.

Kennedy and Environmental Protection Agency Administrator Lee Zeldin held a press conference last month praising Utah’s decision, and the HHS said the Health secretary is convening a task force to develop new Centers for Disease Control and Prevention guidance on the issue, likely removing any recommendation for fluoride to be included in drinking water.

And on Wednesday the day before Paxton announced his investigation Florida lawmakers passed a bill making that state the second to outlaw fluoridation in water.

Paxton’s investigation argues that major companies are causing parents to exceed healthy doses. His press statement accuses Colgate and Procter & Gamble manufacturers of Colgate and Crest toothpastes of using flavoring and marketing to “encourage kids to ingest fluoride toothpaste and mislead their parents.”

A 2024 study in Nature found that parents tend to “significantly” overdose toddlers’ toothbrushes with fluoridated toothpaste. Specifically, the study found they tended to overload toothbrushes by a factor of six to seven times the recommended amount a rice-sized amount for children under 2.

The Hill has reached out to Colgate and Procter & Gamble for comment.