Orthodontists typically take multiple x-rays of the entire skull before, during, and after treatment. While the amount of radiation is small, the repeated exposure can be a concern, especially for pediatric patients who are generally more susceptible to its harmful effects than adults. But researchers at the Harvard School of Dental Medicine suggest that 3-D imaging could provide a better diagnosis while using less radiation.
Orthodontists use the cranial base of the skull as a stable reference for determining the position and orientation of the jaws and teeth in planning treatment changes. However, non-radiographic 3-D dental photogrammetry could offer accurate dental and facial measurements based on using the eyes and natural head orientation as references instead.
“The method developed uses 3-D photographic images to capture the face and teeth and use the eyes as a reference instead of the cranium. This allows the orthodontist to limit the x-ray exposure to the area of interest, which is just the teeth and surrounding bone, allowing sensitive parts of the body like the brain and eyes to be avoided and shielded during the radiographic exposure,” said Mohamed Masoud, DMSc, BDS, director of orthodontics in the school’s department of developmental biology.
The researchers studied 180 females and 200 males between the ages of 18 and 35 years using 3-D facial and dental imaging to produce an adult sample with near ideal occlusion and a pleasing facial appearance. The goal was to provide reference values that can aid practitioners in determining the relative position and orientation of dental and facial structures without exposing the cranium to radiation.
A follow-up study validated the method on an adult orthodontic population, showing it led orthodontists to the same treatment plan radiographic records. Now, the researchers are working with local Boston schools to develop age-specific and race-specific 3-D photographic standards to diagnose and plan pediatric orthodontic patients.
“These standards are still being developed and tested,” said Masoud. “Our hope is that these new 3-D facial and dental imaging methods will eventually become the standard of care for orthodontic diagnosis, which will reduce the radiographic burden of the specialty.”
The study, “3D Dentofacial Photogrammetry Reference Values: A Novel Approach to Orthodontic Diagnosis,” was published by the European Journal of Orthodontics.
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