Dr. Thomas was raised in Tempe, about a mile from where his father built the dental office that he has practiced at for the last twenty-five years. He graduated from Tempe High and after attending Brigham Young University he graduated from Oregon Health Sciences University in Portland as a D.M.D. in 1985. After graduation Dr. Thomas completed an orthodontic program of continuing education that included both a didactic and practical portion, seeing patients on a monthly basis for a three year period. The completion of this training qualified him to treat orthodontic patients.

His training was carried out under the guidance of Dr. Richard A. Litt, Professor and Chairman of the Department of Orthodontics at the University of Detroit from 1969-1980, and Clinical Professor and Director of Postdoctoral Orthodontics at the University of California, San Francisco, from 1980-1986. In 1985 he founded the Faculté for Orthodontic Research and Continuing Education, F.O.R.C.E., the program of education completed by Dr. Thomas.

On completion of his studies Dr. Thomas returned to Tempe to practice dentistry with his father, Dr. Elmo Thomas, together they built a strong practice. In 1992 Dr. David Thomas took over the practice; his reputation, built on honesty and integrity, has enabled him to establish long-term patient relationships with new patients as well as continuing to treat many of the patients that first came to see his father over forty years ago. Many of the new patients joining the practice are referred from existing patients, a testament to the esteem in which they hold Dr. Thomas.