According to Wikipedia:
The first dental school, Baltimore College of Dental Surgery, opened in Baltimore, Maryland, USA in 1840. Philadelphia Dental College was founded in 1863 and is the second in the United States. In 1907 Temple University accepted a bid to incorporate the school.
Studies showed that dentists graduated from different countries, or even from different dental schools in one country, may have different clinical decisions for the same clinical condition. For example, dentists graduated from Israeli dental schools may recommend more often for the removal of asymptomatic impacted third molar (wisdom teeth) than dentists graduated from Latin American or Eastern European dental schools.
In the United Kingdom of Great Britain and Ireland, the 1878 British Dentists Act and 1879 Dentists Register limited the title of “dentist” and “dental surgeon” to qualified and registered practitioners. However, others could legally describe themselves as “dental experts” or “dental consultants”. The practice of dentistry in the United Kingdom became fully regulated with the 1921 Dentists Act, which required the registration of anyone practicing dentistry. The British Dental Association, formed in 1880 with Sir John Tomes as president, played a major role in prosecuting dentists practising illegally.
In Korea, Taiwan, Japan, Sweden, Germany, the United States, and Canada, a dentist is a healthcare professional qualified to practice dentistry after graduating with a degree of either Doctor of Dental Surgery (DDS) or Doctor of Dental Medicine (DMD). This is equivalent to the Bachelor of Dental Surgery/Baccalaureus Dentalis Chirurgiae (BDS, BDent, BChD, BDSc) that is awarded in the UK and British Commonwealth countries. In most western countries, to become a qualified dentist one must usually complete at least four years of postgraduate study; within the European Union the education has to be at least five years. Dentists usually complete between five and eight years of post-secondary education before practising. Though not mandatory, many dentists choose to complete an internship or residency focusing on specific aspects of dental care after they have received their dental degree.