Dr. John C. Greene
San Francisco, CA Dentist
Among his many appointments Professor Greene has held two of the highest positions in the field of dentistry. He is Dean Emeritus of the University of California San Francisco, School of Dentistry and served as Deputy Surgeon General of the U.S. Public Health Service. He is a world renowned researcher, lecturer and author and has been studying the health effects of using spit tobacco among professional baseball players since 1988.