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.
List of 10 tallest buildings in the world from base to roof (Topped-out before 2015): Burj Khalifa (Dubai, United Arab Emirates) --- 828m (2,717 ft.), 163 storeys. Makkah Royal Clock Tower Hotel (Mecca, Saudi Arabia) --- 530m (1,740 ft.), 120 storeys.