Crowns and Root Canal on 3 yr old

After my 3 year old's first visit to the pediatric dentist, I was told that he needs 3 front teeth crowned and a root canal, as well as a cavity filled!  I had a feeling that my son's teeth needed some work (perhaps a cavity or 2), but not this much work!  Yes, I did brush at least twice daily, but admittingly gave him juice at night without rebrusing.  I feel awful.  Unfortunately, my son has severe food allergies, including milk allergy, and basically drank juice and water...yes, mainly juice.  I was also told that he will need to have all his dental work done under general anesthesia at a near by surgery center.  My question is regarding the crowns to the front teeth.  The ped dentist did show me a model of a crown - white in the front, and silver behind the tooth.  How will crowned teeth really look?  The dentist stated that the color of the crowns will be whiter than natural teeth.  What about the silver part?  Will there be an obvious silver lining around the front teeth?  It's bad enough that he is so young with so much decay, but how will he really look with the crowns?  Thanks for a response....his dental work will probably be done in 3-4 weeks....