Does https://hyperfine.io/ fit the bill?

No, but it’s a step closer. CBCT is the standard right now, but it has limitations like poor bone density measurement and no dynamic imaging.

Having just had a wisdom tooth extracted, something that can help them locate nerves for targeted local anesthesia would be nice. In both this and a crown procedure I had done ten years ago the needle hit a nerve bundle and it felt like my face was getting tazed lol.

Just because I'm curious, what benefits would fMRI provide to oral surgery?

An fMRI quality imaging system would allow dynamic planning for a full arch implant retained prosthesis, for example.

But wouldn't a standard structural/anatomical MRI work better than fMRI for that purpose?

I guess fMRI isn’t really a good analog. What is needed is an MRI quality video sequence showing movement. Dynamic planning would allow occlusal schemes to be designed more accurately, therefore avoiding many common issues with full arch rehab, for example.

None. You can't have any metal beside the MRI scanner, the strong magnetic field turns it into projectiles.