Imagine a seven-year-old child sitting in a dental chair, slightly anxious, waiting for a panoramic dental X-ray. The image will determine whether the teeth are developing normally, whether there are hidden cavities, or whether there are abnormalities that have not yet been detected. The problem is that the upper and lower anterior regions—the very areas that are most critical to evaluate—often appear blurred on standard images. The dentist must then decide: take an additional image and increase radiation exposure, or rely on an image that may not be sufficiently clear?
drg. Isti Rahayu Suryani, M.Biotech., Sp.RKG, Subsp.RDP(K), Ph.D., from the Department of Dentomaxillofacial Radiology, Faculty of Dentistry, Universitas Gadjah Mada, refused to accept this dilemma as unavoidable.
One Exposure, Multiple Layers Automatically Selected
The study, published in Imaging Science in Dentistry in 2018, involved 50 digital panoramic radiographs of children aged 6–12 years with mixed dentition, the developmental stage in which primary and permanent teeth are simultaneously present in the jaws. This is one of the most complex periods of dental development, making accurate diagnostic imaging particularly important.
All images were acquired using a VistaPano device from Dürr Dental and processed using Smart Panoramic (S-Pan) technology. The principle is elegant: from a single X-ray exposure, the device captures multiple parallel layers simultaneously. Each layer is automatically segmented by an algorithm, after which the sharpest and most focused fragments are selected and reconstructed into a complete panoramic image. No additional exposure is required. No repeat procedure is necessary.
The resulting images were compared with the original, unprocessed images. Two maxillofacial radiologists independently and blindly evaluated the anatomical structures using a modified scoring system based on Choi et al., which assessed structural clarity on a scale from 1 (not visible) to 5 (clearly visible in all regions).
The Anterior Region Becomes the Turning Point
The most striking findings emerged in the anterior region—the upper and lower front teeth. This was where the difference between the images before and after processing was most dramatic and statistically significant (P < 0.05) for all evaluated anatomical structures.
The greatest improvement was observed in the periodontal ligament space and lamina dura of the permanent teeth, with a mean score difference of 1.86 points. Structures that had previously been barely visible became considerably clearer. The crowns of permanent teeth even achieved a mean score of 4.56 out of 5, approaching an optimal level of clarity.
Why is the anterior region so difficult to image? The answer lies in the geometry of panoramic imaging. The curved position of the anterior teeth often results in overlapping structures and blurring caused by the shadow of the cervical spine. S-Pan technology effectively eliminates this interference by selecting only the most focused image fragments.
“This technique allows better visualization of the anterior regions of the maxilla and mandible without blurring caused by ghost-image artifacts from the vertebral column,” wrote drg. Isti Rahayu Suryani and colleagues in the paper.
Meanwhile, the maxillary premolar region showed no significant overall difference, except in the root morphology of permanent premolars and the trabecular pattern of the alveolar bone. This is consistent with previous literature: the posterior and premolar regions are naturally more stable in panoramic imaging because of their position closer to the device's focal plane.
Consistent Assessments, Not Just Good Fortune
Another factor strengthening these findings was the high inter-rater and intra-rater reliability. For the anterior region, agreement between the two observers reached kappa values above 0.82, classified as excellent. For the premolar region, kappa values were above 0.63, classified as good. These values remained consistently high for both the original and processed images.
This means that the evaluation did not depend on who viewed the image or when it was assessed. S-Pan-processed images produced stable and reliable assessments—a critical requirement for any diagnostic method intended for clinical use.
This research was part of an international collaboration involving UGM, KU Leuven (Belgium), Universidad de Los Andes (Chile), Universitas Padjadjaran, and Karolinska Institutet (Sweden), funded by the AREAS Erasmus Mundus Action II program. The scale of this collaboration was more than an academic formality—it reflected the fact that questions surrounding radiation safety in children are global concerns requiring collective solutions.
In pediatric dentistry, every decision to obtain an X-ray involves balancing diagnostic benefits against radiation exposure. Image-processing technologies such as S-Pan offer the middle ground that clinicians have long sought: better images without requiring children to undergo additional radiation exposure.
Source DOI: https://doi.org/10.5624/isd.2018.48.4.261
Authors: Anny Anggraini; drg. Achmad Zam Zam Aghasy, M.Kes.
Photo: Pexels