Can I Sell an Old Dental Bridge or Use the Same Material for a New Bridge?

The material from old crowns and bridges really can't be reused for a new bridge. Even if sold for scrap, the porcelain can't be reused and there is not enough precious metal to pay the cost of a new bridge. Most of the cost of a new crown or bridge is in the labor, not the materials.

You are not please with the aesthetics of your present bridge and want to get a new one. Dental Bridges are expensive.  Most of the cost of a bridge is tied up in the labor that the lab technician invests in designing and customizing the bridge for your mouth and aesthetics.  A portion of the cost is associated with the labor and materials used by the dentist to design the bridge, prepare the teeth, adjust the fit and place the bridge on the prepared teeth.  The actual value of the materials that make up the actual dental bridge is relatively small.  Most dental alloys contain a small percentage of gold.  The non-precious metals are added for strength.  The porcelain can not be reused.  The gold alloy can be reclaimed, however the cost to extract the gold from the allow makes the payback minimal.  Several pounds of dental bridges containing gold alloys may yield less that $100 through reclamation.  Reclaiming dental gold alloy is not the same as trading in old gold jewelry.  Personally, a coffee cup full of abandoned dental work collected over 15 years barely covered taking my young family of four out to a local burger joint.  It was a nice treat, but not a source of income by any stretch of the imagination

Esthetic component of the final restorations - crowns or bridges is part of an overall success. Modern techniques and materials allow to create natural look  for the crowns.  It usually takes art for a team of dentist and lab technician to create the restorations that will look like natural teeth. And if the patient is unhappy with existing crowns and bridges it is reasonable to change them. 10 unit bridge with 4 abutment teeth seem like a questionable construction, due to too many teeth, too little support. Fixed crown and bridge work on teeth can be long-term solution in multiple cases which was supported by various research. And the long-term research show that 2 teeth can not effectively handle the occlusal load for 5 teeth without changes in periodontal ligaments and surrounding bone. Long term prognosis is optimal for 2 strong abutment teeth that can have a load for 1 pontic. Abutment teeth will start suffer at some point and loose periodontal and bone support, get mobility.

So, before you will consider changing the existing bridge your dentist will re-evaluate current condition of abutment teeth and probably alter the type of final prosthesis. After removal of old restorations patient will have the provisional crowns or bridges till the end of the treatment. Usually in big practices (prosthodontic, general dentistry) metal from old restorations is collected and send to one of the companies which utilize it.

You can try to contact with one of these companies and sell it yourself, but you will be surprised how little it will cost. Most optimal metal for crown and bridge is  high-noble with high content of gold and platinum. The metal from previous restoration is not used for the new one because it has to be absolutely free of any oxides that occur from baking the porcelain on top of it and after many years being in the mouth.