Investigating the demineralisation of hydroxyapatite by kombucha and hard seltzer using atomic force microscopy

While the erosive potential of acidic beverages has been known for decades, many new and increasingly popular beverages and food fads have not been evaluated quantitatively for their dental associated risks. In this study, the authors utilise atomic force microscopy to monitor changes in the surface morphology of an enamel mimic, hydroxyapatite (HA), induced by hard seltzer and kombucha. The primary causes of enamel degradation were assessed through a combinatorial investigation probing the impact of carbonation, acid type, acid concentration, and saliva. The average surface roughness of HA discs was determined after successive demineralisation steps. The heterogeneity of the decay process was assessed using multiple spatial replicates per sample. To aid in the interpretation of the HA decay profiles, pH and titratable acidity of each beverage were also measured. The authors find that, in comparison to a reference sample of Coca-Cola®, kombucha is equally erosive after prolonged exposure while hard seltzer results in relatively minor surface damage. In addition, the presence of saliva was found to eliminate any measurable amounts of decay. Results from this study demonstrate the potential damage more recently popularised beverages can have on dental enamel and the significant dependence of oral health on the presence of saliva.