[Linda Buquet]

No one can tell you the best niche for you, but I question how and why you are picking certain key words.

Take dental products for example.

Why those KW? Are they highly popular but low in competition?
Or how and why did you pick that phrase.

Do you know alot about dental products and are you interested in the topic?

Do you think there are affiliate programs with products that would be lucrative? Are there products online people can't buy in local grocery stores?
Would consumers search that term or is that term searched more by dental professionals. (Check Google - I think it's the latter, in which case it's much harder.)

Do you think it would be easy for you to generate content and write articles on the topic?

Just giving you some things to think about as you research niches, using that one phrase as an example.