He recommends a natural toothpaste that leaves the mouth's acidic balance neutral, as well as dietary changes, like minimizing acidic foods.

WSJ: Deluxe Toothpastes: Brush With Greatness

Timothy Anderson, an analyst at Prudential Equity Group who is neutral on Merck shares, wrote in a note to investors that the decision was on balance a negative for Merck.

FORBES: Merck's Uncertain Future