Hydroxyapatite toothpaste is a fluoride-free option that has some research backing its effectiveness. mihailomilovanovic/Getty Images hide caption

mihailomilovanovic/Getty Images

How you brush your teeth — and what you use to do it — matters.

Recently, dentist Dr. Jin-Ho Phark says he's noticed patients asking about fluoride-free toothpaste options. Phark is an associate professor of clinical dentistry at the Herman Ostrow School of Dentistry of University of Southern California.

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

One product that patients are asking about in particular is a calcium phosphate mineral called hydroxyapatite. Many patients, Phark says, may have seen the products on social media, "being pushed by influencers and other people quite intensively."

The traditional fluoride toothpaste became common in the late 1950s , according to the Centers for Disease Control and Prevention, when Procter & Gamble Co.…