Complex sentence: The Canadian Association of Orthodontists was founded in 1949 by a group of orthodontists attending an annual convention at the American Association of Orthodontists at the Commodore Hotel, New York, USA.
Split into simpler sentences: The Canadian Association of Orthodontists was founded in 1949. By a group of orthodontists attending an annual convention at the American Association of Orthodontists at the Commodore Hotel, New York, USA.