Dr. Gregston was born and grew up in Duncan and graduated from Duncan High School in 1989. His ties to the Duncan medical community stem from his grandfather, Jack L. Gregston, M.D. who has practiced in the area for over fifty (50) years.

A 1996 distinguished graduate from the University of Oklahoma College of Medicine, Dr. Gregston completed his residency in Emergency Medicine at the University of Oklahoma Health Sciences Center in Oklahoma City in 2000.

He, his wife Jill, and their children immediately returned HOME to Duncan. He served as Co-Director of the Emergency Department at Duncan Regional Hospital from 2001-2005 and presently enjoys using his ER skills to care for minor emergencies and many other health care needs in the urgent care clinic that he and Jill established November, 2005.

Dr. Ivory graduated from Marlow High School, and finished his undergraduate education at Oklahoma State University. He attended medical school at the University of Oklahoma and did his residency training at the University of Oklahoma in Tulsa.

After completing his residency, he returned home to practice medicine and serve his patients in Family Practice here in Stephens County. He stands on the premise that we are all very Blessed and Thankful for all of our patients, and the fact that they allow us to be a small part of their lives.

Dr. Ivory was named the Duncan Banner's Reader’s Choice Most Exceptional Physician for the second year in a row this Fall (2016).