More and more non-smokers who are young are getting oral cancer. I hear this anecdotally from doctors and institutions who are treating people all around the country. I think that your blaming your braces and orthodontist for your condition is misplaced blame. There is no scientific peer reviewed literature that conclusively ties long term trauma to oral cancer. You see this listed occasionally on some sites as a cause, but there is no evidence to back it up. If braces and the trauma and irritation that they induce were the causative factor in oral cancers, you would see a lot of this in that particular population of individuals that wear braces. You do not see this. Right now the important thing is to get through treatments and get cancer out of the picture. When the dust settles, you can look for cause. I too was a relatively young (by oral cancer standards) person who never used tobacco who got oral cancer. It turns out that both my wife and I are HPV 16/18 positive, and I believe this is the cause in my case and in many other non-smoker