Here's a sulfate-free toothpaste that's ideal for sensitive mouths. With nearly a five-star rating and over 6,400 customer reviews from Amazon shoppers, its gentle, pH-balanced formula aims to restore eroded enamel. One satisfied customer writes that ClōSYS is, "[The] best toothpaste in the world! I can say that from a professional standpoint, since I have been a dental hygienist since 1984, and have used these products since the early 1990s. The inventor of this product was the doctor who wrote my 'Periodontal' college textbook."