Dr. Hammen is a native of Mexico, Missouri but moved to Owensboro at age 12. He graduated from Daviess Co. High School and went to college at the University of Kentucky. He graduated with honors with a bachelor degree in biology. He then stayed in Lexington receiving his doctor of dental medicine from the University of Kentucky College of Dentistry. He was then accepted into the Oral and Maxillofacial Surgery residency at the University of Cincinnati.

At this time, he received extensive training in dentoalveolar surgery, anesthesia, trauma, reconstructive bone grafting, implants and medicine. In the last year of the 4 year program, he served as chief resident caring for patients at the University Hospital, Cincinnati Childrens Hospital Medical Center and the VA Hospital.

Dr. Hammen is a board certified by the American Board of Oral and Maxillofacial Surgery (ABOMS) and is a fellow of the American Association of Oral and Maxillofacial Surgery (AAOMS). He is also a member of the Kentucky Society of Oral and Maxillofacial Surgery (KSOMS), American Dental Association (ADA), Kentucky Dental Association (KDA), and the Green River Dental Society.