Most of the things (rice, flour, wine, tinned tomatoes) you've listed are cheaper in California but definitely NOT dental work. When my husband needed his wisdom teeth removed, we did the same thing. Compared prices for a few SD dentists and called to a few dentists in Blenheim. The cost of the work in SoCal was the same as taking two weeks off, buying return tickets to NZ, and paying for the dental work. Unfortunately, arranging the consultation visits made it unrealistic because he needed it done pretty quickly. But yeah, a huge difference there.