10 days ago 3 diff dentists took a ton of intra-oral x-rays for my #29, all in a few hours. now, a specialist needs a digital extra-oral. is it safe?

Dental x-rays: A unit called a “rem” is used to measure radiation. It takes 1000 mrem to equal one rem. Dental x-ray image exposes you to only about 2 or 3 mrem. Dental x-rays have an upside and a downside. Risks from dental x rays are very small when compared with other medical exams involving radiation exposures. Without dental x-rays there is no proper diagnosis and/or treatment. Take care.

You may not have cho: I would say it is safe; for now you do not have much of a choice.But in future you can always decline "routine x-rays" that some dentists like to do every year. I skip /delay those when I have no obvious tooth trouble.