For what it's worth - a friend of mine is a dentist and he mentioned once that white fillings (the ones that are set with an UV light) start to shrink after 5 y

For what it's worth - a friend of mine is a dentist and he mentioned once that white fillings (the ones that are set with an UV light) start to shrink after 5 years. On the other hand, silver filling will do the same after 10-15 years and at a slower rate. Whether this shrinkage will lead to problems is a separate question.