Here in NZ people would be introduced as Dr if they hold either PhD or medical degree (the title of the medical degree here is MbCHb or something like Medicinae bachelorae Chirugeonae bachelorae which translates to bachelor of medicine and surgery from latin, so nothing about Dr in the degree title). Most people would probably use Name followed by PhD if they were not a medical dr, but it would depend on the person and context - they may use the title in a professional context, but not the rest of the time.
I agree with Trof regarding the one true Dr, but this one is pretty cool too:http://lmgtfy.com/?q=dr+teeth
seems really weird to me to be honest to use that title.
I really don't see the point using it unless in a scientific context and even than...
Sorry, missed that bit in my reply - Dr would only be used in a formal setting such as if you were introducing someone new in a professional setting. The rest of the time just the person's name would be used without even Mr, Mrs...etc.