 Dr. De Soto then introduces a new formula the couple created recently, and claiming that one application will prevent toothaches forever asks the fox if he'd like to be the first to try it, who, hating pain, readily agrees.The dentist takes his time and paints each tooth with the formula, then has the patient clench his jaws shut for a full minute.The fox is surprised to find that his mouth has been glued shut, as this is what the secret formula really is, but Dr. De Soto states that he "should have mentioned" that the formula needs time to permeate the dentin and as a result, the fox will not be able to open his mouth for a day or two.