Strategies against acid induced hydroxyapatite dissolution of human dental enamel
Dental erosion is the dissolution of dental hard tissue without the involvement of bacteria. It is well known that acid containing food and beverages lead to the erosive damage of dental enamel. This disease occurs mainly in children and has increased dramatically in the last years and, thus, moved in the focus of scientific investigations. The current work investigated the process of tooth erosion with an in vitro model system and developed new strategies against the process of dental erosion based on the modification of erosion inducing acidic soft drinks. Influencing factors were systematically changed and the erosion effect on in vitro enamel was investigated quantitatively and qualitatively. New insights are presented to much better understand the process of erosion and to possibly reduce the erosion on human dental enamel. Profilometry and AFM-based nanoindentation were used to investigate the long time and the short time erosion process on human dental enamel. Moreover, different food-approved polymers (propylene glycol alginate, high-esterified pectin and gum arabic) were investigated for their erosion inhibiting effects. The addition of these polymers to citric acid solutions showed a significantly reduced hardness loss of enamel compared to enamel treated with unmodified citric acid solutions. The current work gives also insights into the interaction of the polymers and the enamel surface in vitro. This interaction led to the formation of a layer consisting of polymer molecules and hydroxyapatite particles, which protects the underlying enamel against erosion caused by citric acid. In addition, with a proper choice of the acids used for soft drinks, the enamel softening can be significantly influenced. The strategies presented in the current study are based on the modification of acidic soft drinks and give the possibility to significantly reduce the acid triggered process of dental erosion.