Saliva has enzymes in it that allow for the partial breakdown of some of the fats and sugars that are in your food. These enzymes nor the other components of saliva are strong enough to breakdown metals. Tongue rings and studs for piercings are typically made of stainless steel. Stainless steel is so corrosion resistant that it is used to make containers that hold strong acids like Sulfuric Acid (H₂SO₄). Since stainless steel can stand up to something as strong as H₂SO₄, it also can resist the relatively mild enzymes in saliva. Cavity fillings (metal or otherwise) are designed to also be inert to saliva so that they will never react with or be dissolved by saliva.

I found an article that says metals in your mouth from cavity fillings can go into your saliva.So I guess the answer is Yes.

The people who wrote the article took samples of the cavity fillings to find out what metals were in them, and they took samples of saliva from people with and without cavity fillings. The people without cavity fillings had silver, chromium, copper, iron, nickel and zinc metal ions in their saliva. Metal ions are atoms of an element with a couple electrons taken away, so they have charges of +1 or +2 or +3. The people with cavity fillings had the same metal ions plus gold ions in their saliva, and most of those people had some metal ions from their fillings in their saliva. The amount of metal in the saliva was different at different times when saliva was taken.