Dr. Mark Johnston graduated from the University of Georgia (UGA), where he received a Bachelor of Science degree in Biology. He entered the Medical College of Georgia in Augusta, and received his Doctorate in Dental Medicine (D.M.D.) degree. After dental school, Dr. Johnston continued his education at the University of Alabama at Birmingham (UAB). He completed a Hospital Dentistry Residency where he received a certificate in Hospital/General Practice Dentistry.
Dr. Johnston was a Research Assistant for the Department of Oral and Maxillofacial Surgery; during the same year, he was a Clinical Instructor for the UAB Department of Restorative Dentistry. He completed his three-year orthodontic residency program and received his Master of Science degree and his Certificate in Orthodontics from the UAB School of Dentistry.
Dr. Johnston returned to Atlanta and opened his orthodontic practice in Marietta. In 2001, Dr. Johnston earned his Board Certification from the American Board of Orthodontics. Only 25% of the orthodontists in the United States are Board Certified.