Dental tourism is growing expotentially. Read this article published in CuencaHighLife back in 2103. Being outdated, it makes a statement to pertaining to the longevity of interest in dentistry for foreigners.
To find what others have experienced with local dentists, go to Gringo Post and type dentist in the search box.
Alternatively, you may choose to visit the Find Health in Ecuador website for assistance in choosing a practitioner.