What is the difference between a composite resin filling a denture and a porcelain venneer?

Percelain veneer is the best, it is made of porecelain in a lab and the color etc looks very natural, teh composite is also a tooth colored restoration, but done in the chair and does not look as good as a procelain, but if doen well can be as good, its also cheaper, a denture means false teeth