National Hydroxyapatite Day is observed on May 29th to celebrate the mineral hydroxyapatite, which is a key component of bones and teeth, providing them with strength and structure. This day highlights the mineral's role in dental and medical applications, including its use in toothpaste to repair enamel and reduce sensitivity, as well as in fillings and implants to enhance bonding with bone. Typical customs for the day include checking toothpaste labels for hydroxyapatite, engaging children in science crafts to demonstrate mineral protection, sharing informative facts about its benefits, and consulting with dentists about its applications. The observance encourages public awareness of hydroxyapatite's contributions to oral health and promotes safer dental care options. National Hydroxyapatite Day was founded by RiseWell, a company focused on fluoride-free dental products, to educate people about this naturally occurring mineral.