dynamic url changed to static, is 301 re-direction needed

Dynamic url changed to static url, rankings dropped

[ashish21cool]

Hi Frndz,

I have a site made in asp.net. I tried to url mask the pages and was successful in doing that. But after doing that i found that my ranks have dropped.
1) I changed the url to static urls' with a trailing slash present. Could this be the reason of drop in rankings.
2) Should you use 301 re-direction to move traffic from dynamic pages to new static pages.

Please help me out.

I look forward to hearing from you.

Thanks,
ashish21cool