Dentists weigh in on hydroxyapatite toothpaste surge

Dentists report a steady increase in patients asking about fluoride-free toothpaste options. Dr. Jin-Ho Phark, an associate professor at the University of Southern California, notes that the shift is driven by social media promotion.

"There's a lot of interest from the patients," Phark says. "I hear that also regularly from students."

The products typically contain hydroxyapatite, a calcium phosphate mineral similar to tooth enamel. Proponents claim the ingredient offers cavity protection, whitening, and enamel strengthening without fluoride.

Dr. Livia Tenuta, an associate professor at the University of Michigan, explains that fluoride toothpaste, which became common in the late 1950s, works by remineralizing teeth with calcium and phosphate.

"When [fluoride is] available in our saliva.. that fluoride that is left over after brushing with the fluoride toothpaste will actually bring minerals back to the tooth," Tenuta says.

Hydroxyapatite operates differently. Nano-hydroxyapatite particles are small enough to penetrate pores in enamel, potentially helping with sensitivity and decay.

Research on the new ingredient shows mixed results. A 2021 study in Scientific Reports tracked 177 children for nearly a year and found similar decay outcomes for users of hydroxyapatite and fluoride toothpaste.

A 2023 study in Frontiers in Public Health followed 171 adults for 18 months and reported similar results. However, Tenuta notes that most studies recruit participants with low caries risk and lack long-term data for high-risk groups.

Dr. Bennett Amaechi, a professor at the University of Texas at San Antonio, states that current evidence suggests hydroxyapatite is as effective as fluoride for remineralization.

"When it comes to remineralization and preventing caries manifestation, it is as effective as fluoride," Amaechi says.

Despite these findings, the American Dental Association maintains that fluoride remains the standard due to extensive historical evidence.

ADA Consumer Advisor Dr. Ada Cooper wrote that evidence for hydroxyapatite remains limited and ambiguous, particularly for specific clinical indications. The organization continues to recommend brushing twice daily with fluoride toothpaste and flossing daily.