How film and tv celeberities have such clean and shiny teeth. I regarly brush but still wonder. Do they use some special products?

LOL. When you make sick money like that, you can afford to have every single specialist, plastic surgeon, trainer, nutritionist, chef money can buy. When in order to keep making money you depend so much on looks, you're sure you do whatever you can to keep it going. It's like any other job in a way. You need to keep sharp in order to keep an edge...
Constant work. Many of these people are under contract, and can have clauses that relate to style: weight, tooth shape and color etc. A lot of veneers, and much bleaching; then no doubt constant and frequent polishing at short intervals. It is the way things are done. Americans are voyeurs, they watch unreal people on tv and that becomes the new normal. It is way over-done.
Blinding White Teeth. The blinding white teeth you see on film and tv celebrities as well as news reporters comes from repeated light or laser assisted bleaching and cosmetic dentistry, namely placement of porcelain veneers. You too can have extraordinarily white teeth if you are willing to pay $500 to $800 for whitening and between $2000 to $6000 for veneers.
No. There are no special products that are available only to celebrities. Many are born with gorgeous teeth. If not they bleach, veneer or have work done to them. Many of their teeth look whiter in pictures because of high flash lighting that is used and never forget about photoshop, magazine covers in particular. Everyone can have a dazzling movie star smile. Just need to see the right dentist.