I ate a bean and cheese burrito from Del Taco and there was a wire in the burrito that scratched the roof of my mouth,

If you have no complications, it would be best to be reasonable. Let them make you an offer. Then negotiate with them until you reach an amount that compensates you for for your injuries as well as pain and suffering.

While it is certainly unfortunate that this happened to you, from the information you provided it does not appear that you sustained much in the way of an injury, aside from the scratch to the roof of your mouth. For the time being I would photograph and save the wire and not release it to anyone else, as doing so runs the risk that it could be damaged or destroyed. In the event you got some sort of infection or other medical problem becaus of the incident you will want to make sure you have safeguarded the evidence. I would wait to make sure that you do not have any more significant problems as a result of the incident. After that you can certainly ask for any settlement figure you want, but I would be surprised if they offer you much given the

You should first seek immediate medical attention as you might need a whooping cough or tetanus vaccine or the injury could become infected, etc... I suspect that Del Taco should be willing to cover all of your medical expenses or at least one would think that would be the case. And you might as well contact a few local experienced and competent personal injury lawyers to discuss the specifics of what happened. Good luck.