On CC we often tell people that in most schools, there is no premed path, and that is certainly true of predental. You can major in anything and go to med or dental or law school. I read a few years ago that music students have the highest admit rate to med school at 62% (wish I could cite this, it was about 4 years ago) The dedication and work ethic that music requires is respected in many contexts.
Majoring in “anything” does mean covering prerequisites and there are programs for that, which I linked earlier.
For undergrad (from the perspective of a parent with three kids who are past college) I would encourage her to think less about the future as she makes her choices (she may lose interest in dental afterall) and more about what she is eager to learn and accomplish in the present, or, should I say, in those 4 precious years.
If she loves music, go for it. If she loves science, go for it. If she cannot decide, go for it and do both. But not for career reasons. I really think that is key. Kids are told, these days, as early as middle school, that they should know their future career. My daughter took a test in 7th grade and the computer told her she would be a conductor or a clown!! Why on earth were they doing this test for such young kids?
Where does the desire to be a dentist come from? Does she love the ocean? Does she love playing the harp?
Does she have other academic interests?
My musician kid applied to all options and ended up at a university where she discovered a love of art history. She is now in a PhD program for music but is glad for that broader experience. She often combines art and music when she teaches undergrads.
But in late April of senior year it was truly 49/50% and she took the whole month to decide. So she had a college experience and is now in a conservatory. She has friends who went to conservatory and are now in a university.
Life is flexible. I hope she can stop planning so much and do whatever she loves, and good luck to her in figuring it out. Lots of time, just make sure she sets things up so she can decide at the end of senior year and you can relax for a bit
ps I am trying not to let any bias slip in because I absolutely love the harp and don’t love my dentist