I recommend seeing a maxillofacial surgeon who is particulary experienced in TMJ disorders.
diagnosis is better made by clinical examination and by MRI of the joint. usually we give steroid injection as a last resort in conservative management of joint pain. a crucial issue is to find out if the main problem is due to muscle disorder or due to intra joint problem. steroid injection is only good for intra joint problem and not for muscle problem. it can give moderate pain for a couple of days. it usually has no complications if given by experienced person but it is highly advisable NOT to be repeated. if you need any help e-mail me: nashaat13@hotmail.com

