nope, I don't think teeth have anything to do with it.
Are you doing BLS or babyfood?
The reason I ask is because with DD I started with traditional baby food - no solids would she take until about 9months. Then I went onto BLS and she was off like a rocket.
DS I started with BLS and while he'll have a go at anything and everything he still only eats 2tbs max at any meal. He was also a slow starter and wasn't real keen on anything until after 8months either...maybe 1-2tspns at a go (not of actual baby food but just to give an idea of quantity).

All kids are different, and I just about did my own head in watching my GFs shovelling food into their kids mouths (all the same age as DS). But once I and realised that my little guy is just different....he' still ok.