Ultra Dex Recalcifying & Whitening Oral Rinse is a clinically proven formula that has been developed for sensitive teeth. The active ingredient within Sensi Shield is Hydroxyapatite, the key natural ingredient block of teeth. Recalcifies tooth surfaces to leave them smoother, brighter & less likely to stain. Provides a protective shield over tooth enamel. Teeth are therefore more resistant to acidic food & drink. Strengthens teeth & whitens by gently lifting organic stains.