1 Add 1/2 cup sugar, the ginger, chicken broth, vinegar, soy sauce, sesame oil, and peanut oil; bring to a boil and cook for 3 minutes.  Dissolve 2 teaspoons of cornstarch into the water, and stir into the boiling sauce.
It is made of harmful microscopic bugs that use sugar to attack teeth. With time this creates a little hole in a tooth, and if not repaired with a filling, the cavity continues to grow. If a cavity is not treated it can destroy a good part of the tooth, making it hard to be rapaired with a conventional filling.
Most things require an expiry date, and most are always on the safe side. In the case with mouthwash and even most medications they just become less affective over time. So don't be surprised if you get a cavity down the road because you used expired mouthwash. I doubt that will happen though. Personally I eat a lot of things that are supposedly expired, if it passes the sight test and the smell test, I move on to the taste test.