Patients ask us all the time what the difference is between composite and porcelain veneers. We explain that composite is a plastic and therefore, porous, weaker, more likely to stain and chip and it has limitations on how big of a filling it can handle. Porcelain is color stable because there is a glaze placed on the outside, it is stronger so less chipping, and can fill in much larger spaces than composite (think if you have big spaces between the teeth, very short teeth you'd like to lengthen, or have broken the edge of a tooth off, for just a few examples). Porcelain therefore lasts much longer, which is one of the reasons why they can cost significantly more than composite.
We explain that composite is like Tupperware and porcelain is like a fine china plate. If you put spaghetti sauce in Tupperware and leave it, eventually it stains, right? But if you place that same spaghetti sauce on a china plate, you can leave it there for months and it won't stain the plate. The glaze keeps the color of the plate intact. That's just one of the benefits of porcelain over composite.