I understand your frustration I've dealt with EC longer than you've been alive.
Can I suggest that you trial excluding toothpaste completely and just use the brushing action preferably an electric toothbrush. Change the brush head and only brush with water for at least one week. If you see a reduction of your symptoms in this time it is likely that the something within the toothpaste is having an irritant effect. I'm not saying your EC is caused from toothpaste, I'm saying you should find out and that it's worth finding out.
For your own sake try to limit your Sugar intake in this time.