On Oct. 23, 1942, Francis Arnold Jr. reported that Syrian hamsters fed a human-like diet developed dental diseases closely resembling those in humans. Although he was never able to repeat his findings, researchers at the School of Medicine and Dentistry at the University of Rochester confirmed them in 1944.

Subsequently, this model became a valuable tool for dental research and eventually led to the breakthrough discovery in 1960 that rampant tooth decay can be caused by a streptococcal infection activated by the frequent eating of sugar.