dear , I am an international dentist also , I live in USA , so what I am going to tell you is about USA only ,
to practice in USA you have to :
1- be graduated from an accredited dental school ( means either from USA or Canada)...
2- Pass the NBDE part 1 (special test for dentists like USMLE part 1 for medical )..
3- Pass the NBDE part 2 (special test for dentists like USNLE part 2 for medical )...
4- pass the state board exam which is a specific exam provided by the state you desire to prctice in ...
So what we do as international dentists , we take NBDE part 1 and NBDE part 2 then we apply for a specific programs in specific dental schools in USA or Canada for 2-3 years (which is not an easy step ) then we do the state board exam after that ...
I hope this will help you as a general view , if you need any help let me know