My temp bridge is yellow? (photo)

The temp bridge gradually stains overtime. They are meant to be in your mouth for only a short time until the final bridge is placed. Unfortunately the only way to get a lighter shade if you are not ready for the final bridge  is to redo the temporary one.

The temporary materials are not as colour stable as the permanent ceramic materials. They tend to stain over time. You may have to get another temporary made for you. You may also consider your permanent treatment abroad. The cost of dental treatment at good clinics in india is a fraction of the cost in the US. The approx. cost of the bridge in US would be somewhere like 3500-4000$, but in india you may get it done for about 700-900$. Even after travel , stay, etc, your total expenses shouldn't be more that 2000-2500$ I guess. So you can have a  holiday to india and still save some money.

It yellowed because of staining and age.  Your best bet is to get another temp made....................