Jayde.... Here's a link to a discussion we just had last week on this subject. In addition to the responses you get on your thread, you may want to read these too. I posted my opinion on the other one. Good luck!
I personally would not shave your pup if you don't absolutely have to. I would think that a really good leave in conditioner (I use Infusium 23 - a human one - on top of the Chris systems stuff) applied very liberally should help you get those mats out. And I mean very liberally. You could always bathe him again after you get them all out just to get the excess conditioner off. You can even try shampooing, conditioning and leaving the cream conditioner on just to comb him out and then rinse. Worth a try anyway before you resort to shaving. I'm sure there are dire situations where people have HAD to shave and start over but hopefully this isn't one of them.
Are you using a conditioner at all? I know when Tatum had to take several baths with a special shampoo from the vet (because she had a bug bite that was making her scratch a bare spot), her hair was super nasty until I gave in and used her conditioner after the special shampoo. You just can't manage a Yorkie's coat without a good conditioner. And the Chris systems Ice-on-Ice spray really helps between baths.
Check out this thread...
http://www.yorkietalk.com/forums/showthread.php?t=11970