Daniel Wilson Something that I've picked up through the years from Sam, Flem, Skramy and my wife, Kris, is that natural teeth have a lot of white in them. When used well, I've found that it can make teeth really look a lot more natural and will give a monolithic restoration a lot more depth. I use white to add decalcifications, mimick craze lines, enhance translucency and oftentimes, it is just what the case needs. I will say this takes a little practice and it is easy to not have enough or too much. For a few of the cases that I will show, I really think it adds a little extra and makes the restorations blend in better. For many of you that see my posts, I often will use the Empress Stain and Glaze Kit on my cases because of it's ease of use. (For IPS e.max, make sure you have the restoration crystallized first if you are going to use Empress Stain and Glaze).
1st Case: VITABLOCS TriLuxe 1M2-A little sunset color stain gingivally but the rest is subtle white striations
Before:
2nd Case: Empress Multi B1 #9-This is an off angle pic but really showcases using white enhance the restoration 
3rd Case: The before is the classic monolithic crown without anything. I used VITABLOCS Mark II 1M1 and just added glaze and some white to attempt to match the white spots
Before:
After:
