My son is an adult now with both ADD and SPD. Most of his friends had braces so he wanted them too. He got them when he was 12 for purely cosmetic reasons and did great. He always had some serious SPD issues but i gave him the choice of getting the braces or not and i acted very non-chalant about the whole think and everything went perfectly. If i had acted like something would go wrong he would have picked up on it and would not have reacted the same way. Try not to let you son see your concerns. Good luck to you and your son. Now that my son is an adult I realize how often I worried unnecessarily.