Abstract
Hydroxyapatite nanoparticles (HAP-NP) are incorporated in oral care products such as toothpastes and mouthwashes to treat dental sensitivity or to promote enamel remineralisation. Despite the good performance of HAP-NP in this application, it is important to ensure its safety for consumers. For that reason, the Scientific Committee on Consumer Safety (SCCS) evaluated the safety of HAP-NP as an oral care ingredient, but the issued opinion was not completely conclusive and the SCCS recommended that additional tests should be performed. Here, we used a commercially available human gingival epithelium (HGE) as a non-animal alternative and MTT cell viability, LDH activity, and IL-1alpha production were evaluated after 3.1% HAP-NP treatment for 10 min, 1 h, and 3 h. Moreover, the absorption of HAP-NP in the gingival tissue was assessed by transmission electron microscopy (TEM) analysis. Finally, the dissolution behaviour of HAP-NP in simulated gastric fluid was also investigated. No deleterious effect was observed for HGE tissues incubated with HAP-NP for all time-points and parameters evaluated. Moreover, a complete dissolution of 3.1% HAP-NP in simulated gastric fluid was observed after 7.5 min at 37 °C. In conclusion, our results evidence the safety of HAP-NP for oral care products with the use of an in vitro replacement alternative for human gingival epithelium and a simulated gastric fluid assay.
Highlights
Hydroxyapatite is an extensively used calcium phosphate for bone regenerative applications in orthopaedics and dentistry [1]
Directive establishes the prohibition to test finished cosmetic products and cosmetic ingredients on animals [8]. Having this in mind and in order to assess the safety of a toothpaste ingredient, it should be taken into account that the toothpaste will be in contact with gingival tissue only for a short period of time (~2 min per 3 times a day); this period could be potentially enough for a mouth cellular uptake
The hydroxyapatite nanoparticles (HAP-NP) morphology show a width between 5–20 nm and length bellow 50 nm
Summary
Hydroxyapatite is an extensively used calcium phosphate for bone regenerative applications in orthopaedics and dentistry [1]. Cosmetics 2018, 5, 53 promoting enamel remineralisation by replacing calcium and phosphate ions to areas from which minerals have dissolved, restoring its integrity and gloss [2,3,4,5,6,7]. Directive establishes the prohibition to test finished cosmetic products and cosmetic ingredients on animals [8]. Having this in mind and in order to assess the safety of a toothpaste ingredient, it should be taken into account that the toothpaste will be in contact with gingival tissue only for a short period of time (~2 min per 3 times a day); this period could be potentially enough for a mouth cellular uptake. The ingredient could be swallowed and absorbed through the gastrointestinal track and potentially become systemically available [9]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
