Berlin 2018 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 7: Biomaterials and Biopolymers (joint session BP/CPP)

CPP 7.3: Vortrag

Montag, 12. März 2018, 10:00–10:15, H 1058

Fluoridation of hydroxyapatite - time dependence and protective properties — •Thomas Faidt¹, Andreas Friedrichs¹, Christian Zeitz¹, Samuel Grandthyll¹, Michael Hans², Matthias Hannig³, Frank Müller¹, and Karin Jacobs¹ — ¹Experimental Physics, Saarland University, Saarbrücken, Germany — ²Functional Materials, Saarland University, Saarbrücken, Germany — ³Clinic of Operative Dentistry, Periodontology and Preventive Dentistry, Saarland University Hospital, Homburg, Germany

The application of fluoride containing products to protect tooth enamel from caries is daily practice for many decades. However, to this day little is known about the time dependence of fluoride uptake in hydroxyapatite (HAP) which is the mineral component of human enamel. In our study, we used highly dense HAP pellet samples as a model system for the crystallites of tooth enamel. To investigate the time dependence of the fluoride uptake, samples were exposed to a fluoride solution (NaF, 500 ppm) for different times. XPS depth profiling revealed a saturation behavior both for the overall amount of fluoride taken up by the sample and for the thickness of the formed fluoridated layer. We found that the maximum thickness of the fluoridated layer is about 13 nm. To explore the efficacy of such an ultrathin layer as a protective shield against acid attacks, we used AFM to determine the etching rates of untreated and fluoridated HAP samples. In spite of very low fluoride concentrations in the fluoridated samples, our results show a strong reduction of the etching rate after fluoride treatment.