Mark Johnston, D.M.D, M.S.

Education & Associations

Dr. Mark Johnston graduated from the University of Georgia (UGA) with a Bachelor of Science degree in Biology. After that, he entered the Medical College of Georgia in Augusta and earned his Doctorate in Dental Medicine (D.M.D.) degree. Once Dental School was behind him, Dr. Johnston enrolled at the University of Alabama at Birmingham (UAB) to continue his education. He completed a Hospital Dentistry Residency, where he received a certificate in Hospital/General Practice Dentistry. Dr. Johnston participated as a Research Assistant for the Department of Oral and Maxillofacial Surgery. During the same year, he was also a Clinical Instructor for the UAB Department of Restorative Dentistry. Finally, Dr. Johnston found his calling at the UAB School of Dentistry where he completed his Master of Science degree and Certificate in Orthodontics following a 3-year residency program.

Once he completed school, Dr. Johnston decided to return to Atlanta to begin his orthodontic practice in East Cobb. In 2001, Dr. Johnston became board-certified by the American Board of Orthodontics. In the United States, only 1 out of every 3 orthodontists hold the honor of being board-certified.

Dr. Johnston continues to support the field of Orthodontics by participating in an extensive selection of councils and professional organizations:

  • Georgia Association of Orthodontists
  • American Dental Association
  • Georgia Dental Association
  • Hinman Dental Society
  • College of Diplomates of the American Board of Orthodontics
  • American College of Dentists
  • International College of Dentists
  • Midwest Component of the Angle Society

Life Outside the Office

When Dr. Johnston is not in the office, he dedicates his time to bettering his local community. He has served as a Partner in Education for Sope Creek Elementary School, Dodgen Middle School, and Dickerson Middle School. Dr. Johnson is also involved with the following philanthropic organizations or projects:

  • Dental mission trips with churches to Peru, Mexico and Honduras
  • Eagles Nest - an Atlanta inner-city mission for the homeless
  • Rainbows - an international organization designed to assist children and adults who have experienced loss of a loved one from death or divorce
  • Rotary Club of East Cobb
  • Citizens Advisory Committee for surrounding public schools
  • Coaching various adolescent sports in the community

Dr. Johnston is a proud resident of Sandy Springs where he shares a beautiful home with his wife Helene. Dr. Johnston and his wife have three daughters named Taylor, Chandler, and Bailey, a son-in-law named Durham, and a son named Watts. In addition to their children, The Johnstons also have three fur babies named Pearl, Greta, Cooper, and Gary. In his spare time, Dr. Johnston enjoys hunting fishing, boating, and spending time in the North Georgia Mountains with his family.

Meet the Team

Dr. Johnston hand-picked his team to reflect the top-level of service he offers to his patients. The Johnston Orthodontics team is a cohesive unit that works hard to meet the collective goal of providing our patients with the most stunning and functional smile that is worth showing off.

The Johnston Orthodontic curated team has over 100 years of combined experience, providing outstanding personalized service is our specialty.

Why Choose Us

When you are choosing the place to transform your smile, you look for a place that will you the very best. How does Johnston rise above other practices?
Johnston Orthodontics stays up to date with the lasted orthodontic innovation including clear braces, aligner therapy, and digital scans (no need for impressions)
Dr. Johnston has been transforming lives and smiles for over 30 years.
Our practice focuses on the individual needs of patients and is equipped to treat children, teens, and adults regardless of age or orthodontic complexity.
Dr. Johnston is a Board-Certified Orthodontist who will work together with your general dentist and other healthcare providers to coordinate your unique treatment plan and guarantee results.
We offer no-interest, flexible payment plans to fit within your budget. For your convenience, we can accept direct payment from your insurance provider.
To guarantee the safety and comfort of our patients, we subscribe to the highest standards for sterilization within orthodontics.
When you choose Johnston Orthodontics, you become part of our family, and we treat you as such. Our office strives to set the bar for professionalism, orthodontic excellence, and client satisfaction.

Two Locations

We offer two convenient locations to serve the areas of East Cobb (Marietta) and Sandy Springs. You can schedule appointments at either location depending on what is most convenient for you. Dr. Johnston serves both locations.

Office Tour

East Cobb

Office Tour

Sandy Springs