Good idea for a niche. Considering your experience, it should be easy. I am sure you know where to find the latest information on the newest products.

Yeah that is a little broad in my opinion, but that type of niche could definitely work!

Sure. It is a great area. People all over the world for the most part care about their appearance. Good job! Check out any and all websites on dental hygiene. Get some good ideas I'm sure. And yes, you want to have interested in your subject matter. Lots!
Rick

Yea, I would probably target a specific type, for example I was thinking of making a site that reviews cost-effective Whitening products, or at-home whitening kits. Something a little more specific