After graduating in 1902, she took graduate work at
Northwestern University through 1903, which led to her specialization in periodontology. After practicing in Columbus for a time, she then went to
Dresden, Germany as assistant court dentist. She was there for two years of study and practice, introducing methods and treatment of
periodontal diseases. Returning in 1908, Dr. Hayden began exclusively practicing
periodontology with the philosophy that care and treatment of gums is as important as caring for teeth. Her office was located at 289 East State Street which was designed by her sister
Florence Kenyon Hayden Rector. The AAWD has established the Gillette Hayden Memorial Fund to aid promising women dental students. She also served as the President of the Federation of American Women Dentists in 1924. ==Suffragist activities==