Dry Mouth

I have had Type 2 diabetes for 4 years and whilst my blood sugar levels seem under control I continue to have a very dry mouth at night. This impacts considerably on my sleep as I am woken frequently with the need to drink. I have mentioned this to my GP who didn't seem to link it with diabetes and didn't come up with a solution. Has anyone else experience this and, if so, how has it been treated? I'd really like to get on top of it and sleep well again.