I have been oil pulling daily for several years and I have a mouth full of various dental things. Fillings, crowns, root canal, etc. I have had no problems at all. I also have a dental implant. So, go ahead and do it.
The more dental work you have the more places for bacteria to hide. So oil pulling will definitely be helpful. Remember that forceful swishing of the oil isn't necessary - just gently work the oil around and your dental work will be fine.