Resin (that is, what is 6d nanometer) is a medical product, which is used to plug teeth in the mouth. Why don't stomatological hospitals do it and let beauty salons do it? Because the effect of resin on front teeth is not good, the color of the reaction is not good. If you want to learn to be careful, someone will find you later. Do you know the shape of teeth? Do you know how much binder is needed for porcelain veneer?