In order to practice, all orthodontists must be licensed by their state. To receive a dental license, candidates must graduate from an accredited dental school, successfully complete the written National Board Dental Examinations and pass state clinical tests.
The world's tallest artificial structure is the 829.8 m (2,722 ft) tall Burj Khalifa in Dubai . The building gained the official title of Tallest Building in the World and the tallest self supported structure at its opening on January 9, 2010. The second tallest self-supporting structure and the tallest tower is the Tokyo Skytree. The tallest guyed structure is the KVLY-TV mast.
Burj Khalifa or Khalifa Tower (Arabic: Ø¨Ø±Ø¬ Ø®ÙÙÙØ©) is a very tall skyscraper in Dubai, United Arab Emirates and is the world's tallest building ever built, at 828m (2,717ft). Before the building opened, it was called Burj Dubai. The building is 160 stories high. Construction of the tower was started in 2004.