Final answer:
The University of Rochester instituted the first two-year dental hygiene program in 1919, following significant earlier contributions by African Americans in the field of dentistry.
Step-by-step explanation:
In 1919, the University of Rochester instituted the first two-year dental hygiene program. The establishment of this program marked a significant advancement in dental education and set the precedent for the formal training of dental hygienists. This initiative followed earlier breakthroughs within the field of dentistry, such as the achievements of African Americans post-Civil War. Notably, Robert Tanner Freeman became the first African American to earn a doctorate in dental surgery, and Ida Gray Nelson Rollins was the first female African American dentist. These pioneers paved the way for future developments in dental education and care, culminating in the creation of structured programs like the one at the University of Rochester.