@tcr0315 What comes to mind to me is a possible skull/spine alignment issue if she had her head tilted back too much compressing the occiput (base of skull) during the dental work. There are some positional spine issues that interfere with circulation to the brain. There have been instances of patients with strokes because of a similar head position at a beauty shop getting their hair washed. There can be muscle spasms that move or twist the upper vertebrae right under the skull and hold it that way. That has happened to me. I am a spine surgery patient and that was happening to me before my surgery for a collapsed disc from bad muscle spasms. I had some episodes of extreme dizziness and vertigo, and that was resolved by my physical therapist who got everything realigned properly. There are some spine conditions, like Bow Hunter's Syndrome, where turning the head also turns the first vertebra and it can get stuck in that position interfering with blood flow to the brain that causes nausea and dizziness. You might ask for a neurosurgeon with an interest in skull base issues, and after that, someone like a physical therapist. I get headaches in my neck and back of head on one side when my vertebra gets turned just a little bit. It can happen if I sleep wrong. Physical therapy has resolved this for me.