Invisalign after Braces

I have already had the full metal wrap around bracket braces on my teeth to correct an overbite and space but I failed to wear my retainer after the braces came off. Due to that mistake I have several spaces between my straight teeth. I no longer have the overbite but I would like to close the gaps. It has been seven years now and I don't know what the right course of action should be. So, I would like to know if Invisalign would be the best way to correct my teeth or would I be able to get another retainer? Thank You,