Your not alone with this one. I have had nothing but problems with my teeth since I have had CRPS. If you can avoid root canals, I would consider it. Every time had a root canal ,I had to have the tooth extracted. My other teeth have become very soft and I have to watch what I eat and how I chew. I talked to my dentist about this and he gave me a script for a high floride toothpaste and told me to rinse with warm salt water 2 times a day. I have had 5 teeth extracted with in a years time. My pain management Dr. thinks it is due to the multiple high end pain meds I take each day. It zapa the body of Calcium. Talk to you Dr. and Dentist and see if supplements might help. My daughter is a Holistic Nutrionist and has me eating steamed broccoli. It is high in nutrients that help to promote strong teeth and bones.
Other then that, I can't offer anymore advise. But, it is a common issue with patients with RSD/CRPS. Good luck!