In 1866, with dentistry still in its infancy as a recognized profession, Lucy Hobbs became the first American woman to earn a doctorate degree in dentistry. Given the lax laws of the times, Lucy Hobbs had been practicing dentistry in Cincinnati since 1861; she had been denied entry into the Ohio College of Dental Surgery because of her female status in the male dominated profession. In 1862 she moved her practice to Iowa amidst the nation divided by the American Civil War. She had joined the Iowa State Dental Society which helped her gain entry into the Ohio College of Dental Surgery, and in 1866 got her degree.
Source: ADA Mews, April 15th, 2019