Pain at the dentist

In January we finally got access to dental insurance. It has been over 10 years since I've been to the dentist for a real checkup and things don't look good. I have five cavities, four of which are under previous fillings. One of these is getting very near the nerve and the dentist isn't sure if it will require a root-canal or not. Ouch. I mean the pain in my pocket-boot. I can deal with the pain in my mouth, but if this requires a root-canal it will really be expensive. While the insurance covers most of the cost of normal fillings, it doesn't pay anything toward major repairs (i.e. root-canals). Add my work to Dec's eight cavities plus the dental insurance premium and I'm really wishing that I had followed my childhood goal of becoming a dentist. If you need the X-ray crystallographic structure of your favorite protein, I'm your man, but currently that seems to be far removed from any practical real-life application. Can I start over in this whole career thing?