Harold "Hal" L. Crossley, DDS ’80, PhD, MS

In recognition of his international reputation and public service as an expert on street drugs, chemical dependency, and clinical pharmacology, as well as his commitment to teaching and mentoring the next generation of oral health and law enforcement leaders, Hal Crossley is the 2025 Distinguished Achievement Alumni Award honoree.

This award honors a University of Maryland School of Dentistry (UMSOD) graduate for significant professional accomplishments in science, dentistry, or education.

Crossley graduated from the University of Rhode Island in 1964 and then earned a master’s degree and A PhD in pharmacology. After joining UMSOD, he completed a doctoral degree in dentistry. In his career, Crossley has excelled as a pharmacist, pharmacologist, educator, author, dental practitioner, and accomplished speaker who has instructed dental students and other dental clinicians and law enforcement officers in the United States, Canada, Europe, Asia, the Caribbean, and Central America.

He attributes his wide-ranging professional path to keeping his mind open to changes. “Don’t get so mired down in what you’re doing that you don’t seize an opportunity, because it could change the whole direction of your life,” he said in 2004.

Often referred to as “Your pal, Hal,” Crossley often was requested by dental students to serve at their graduation ceremonies and was voted Teacher of the Year several times. He is a popular draw at UMSOD’s Continuing Education classes, and his topics have included the effects of physician-prescribed medications on dental treatment, recommendations on antibiotic prophylaxis, and the signs and symptoms of substance abuse among patients and dental professionals alike.

“I don’t teach just because it’s a job. I try to instill in students a sense of excitement and enthusiasm,” he said.

Crossley, now a Professor Emeritus, helped to write the first edition of the “Drug Information Handbook for Dentistry” with Richard L. Wynn, PhD, Professor Emeritus, Department of Neural and Pain Sciences, and Timothy F. Meiller, DDS, PhD, professor, Department of Oncology and Diagnostic Sciences, both of UMSOD. Now in its 30th edition, it is the most recognized chairside dental drug reference book.

After a chance encounter with members of the U.S. Drug Enforcement Administration (DEA), Crossley was asked to speak to law enforcement officers. Soon after, he was speaking at countless law enforcement agencies throughout the country, leading courses on the pharmacology of street drugs including heroin and cocaine.

For almost 40 years, Crossley served on the Maryland State Dental Association’s Well-Being Committee. He is a member of Phi Kappa Phi, Omicron Kappa Upsilon National Dental Honor Society, the American College of Dentists, and the International College of Dentists. He served as a consultant for the DEA and other law enforcement agencies and, in 2008, received the Gordon J. Christensen Lecturer Recognition Award from the Chicago Dental Society. Crossley is one of 12 dentists (in 113 years) to be honored as member of the Thomas P. Hinman Dental Society. 

Upon his retirement from UMSOD in 2004, he said, “I’ve just had a wonderful experience. I’ve been blessed with good health, a wonderful family, and friends. I feel very fortunate.”