Dr. Clark was in private practice from 1983-1989. From 1992-1997, he was in periodontics private practice. In 1998, Dr. Clark joined joined the College of Dentistry Department of Family Dentistry as a visiting assistant professor; he is now a clinical associate professor.
Dr. Clark participates in intramural dental practice in the Department of Periodontics.
Dr. Clark is a member of the Iowa Dental Association, the American Academy of Periodontics, and the American Dental Association.