Johnson and Johnson make ACT mouthwash, a fluoride rinse. It is sold
in the US, and can be ordered online.

http://www.jnjoralhealth.com/act/professionals.html

I couldn't find anything at the Shoppers Drug Mart website. In the US,
it is sold at grocery stores, discount stores, pharmacies, etc. Places
like Kroger, Ralph's, Rite Aid, Target, Walmart, etc. So maybe Zellers
or Canadian Tire or who knows where.

If you're near the border, cross over and pick some up.

Any chance you're brushing too hard or too often? That plays havoc on
enamel. If your brush looks like an old broom after a few weeks,
you're brushing too hard.

Other ways to keep your teeth clean include chewing sugarless gum after
eating or eating cheese at the end of a meal. The casseins in cheese
supposedly suppress cavity bacteria. There are even chewing gums that
have these added, to improve teeth cleaning between brushing.
Greg Zywicki