“…Tea protects teeth against erosive demineralization [3][4][5][6][7]9] because the chemical structure of hydroxyapatite (HA), which comprises enamel, is tolerant to substitution by different trace elements [51,52]. Reports using liquid solutions [53,54] have shown that Zn, Ca, Mg, Fe, K, and Cu, which are found in tea, are involved in tooth staining.…”