Do you clean your teeth before going to a dental appointment or let the dentist do it?

I would never brush or floss before, unless I had just eaten something awful within the last hour or so. I think it is best to stick with your normal routine. You give the hygienist a better look at how good or bad your cleaning is. They can easily tell what is recent and what has stuck to the teeth and requires scaling. Furthermore, you aren't saving them any stink. The stuff that you need their help to clean out smells about 50 times worse than the things you just ate (just smell your floss compared to your breath after any meal). A quick rinse with water will get the worst out of their way, and even if you're a sloppy eater the rest will take maybe 5 minutes at worst to remove.