I have, I normally have my teeth checked when I go to abroad. The good thing is that you get a very good quality service and preventive dentistry (apart of some well needed holidays), the bad part is that if something goes wrong you need to go all the way over there again which sometimes may not be cost effective.
For example, I have had an operation with a maxilofacial surgeon to remove a wisdom tooth that grew downwards rather than upwards. The operation was very fast and tbh perfectly done. Obviously was private therefore not cheaper than in the NHS (but hey, considering how difficult it was to make a simple appointment with a dentist who invariably said that he wanted to see how things evolved for some time and then wait for a life time for yet another appointment to be told to eait for another appointment I think that 4 yrs on I would still be waiting to have the operation)
My bad experience was having a root canal done abroad, the surgeon was good and the work was guaranteed to be repeated at no cost if it was not properly done, well, after a couple of weeks we notice that it needed to be re done but by the time I was already back in England and it would have costed me other £500 to fly there again, so I consider that I sent 500 dlls down the drain with that root canal...