Thank you, @ken82. My doctor told me that many people are on prednisone way too long, and I was put on a tapering schedule that started two weeks after I started taking it. My bone scan was done right when I started the prednisone so I don't think it had time to impact my bone density. I have an autoimmune disorder so will probably be on it, on as low a dose as necessary, for a few years. My teeth are good so far!