Is my new gum giving my canker sores?

After getting my second cavity this summer, I decided to start chewing sugarless gum. I’ve been a big Wrigley’s guy all my life, but it just wasn’t worth the pain of getting that cavity filled. I started chewing Trident which I prefer over Wrigley’s sugarless gum, becaue Trident doesn’t have aspartame (from what I could see on the label). So is it Trident giving my canker sores? Is there anything in it that would do that? Is my mouth rejecting the non-Wrigleys product that I’ve been using?

The other thing it could be (and is more likely) is that school just started up again. On a previous visit to the dentist (around finals) I asked him why I was getting canker sores now when I’d never gotten them before, and he said it was probably the stress of finals.

So is it my gum (I hope not) or school? If it comes down to it, I think I would be willing to quit school if that’s what it would take to get rid of the canker sores, but I don’t think I could live without my gum.