A Comparative Evaluation of Digital Periapical Radiography and Cone- Beam Computed Tomography for Assessment of Intrabony Periodontal Defects

Every day, millions of people around the world battle a silent, chronic inflammation that slowly eats away the bone holding their teeth in place. This condition, known as periodontitis, is a leading cause of tooth loss in adults. When the disease advances, it creates deep, vertical trenches in the jawbone called intrabony defects. For a dentist to save a tooth, they must first understand the exact shape and size of these hidden trenches. If the measurements are wrong, the treatment plan could fail, leaving the patient with a tooth that is doomed to fall out. To see these invisible structures, doctors rely on X-rays. For decades, the standard tool has been a digital periapical radiograph, a flat, two-dimensional image that is cheap, quick, and exposes the patient to very little radiation. However, a newer technology called cone-beam computed tomography has emerged, offering a three-dimensional view of the jaw that reveals details the flat images miss. This new method is far more detailed, but it is also significantly more expensive and delivers a much higher dose of radiation. The medical community has been left with a difficult question: Is the extra detail from the 3D scan necessary for every case, or does the old-fashioned flat X-ray tell the story just as well for the most common measurements?

A team of researchers at Chitwan Medical College and KIST Medical College in Nepal set out to answer this question by putting the two technologies head-to-head. They gathered thirty-six adults who were already diagnosed with periodontitis and had at least one of these deep bone defects. The goal was simple: measure the same defect on the same person using both the flat digital X-ray and the 3D scan, and see if the numbers matched. The researchers focused on four specific dimensions that guide treatment: how tall the defect is, how deep it goes, how wide it is at its widest point, and the angle of its walls. To ensure fairness, every participant had only one defect selected for the study, and the same trained examiner took all the measurements using carefully calibrated software. The flat X-rays were taken with a special device to keep the angle perfect, while the 3D scans were reconstructed into slices that aligned exactly with the long axis of the tooth.

When the researchers compared the results, the two methods produced nearly identical numbers. The flat digital X-ray measured the height of the defects at an average of 3.85 millimeters, while the 3D scan measured them at 3.95 millimeters. For depth, the flat image showed an average of 7.72 millimeters compared to 7.90 millimeters on the 3D scan. The width and the angle of the defects showed similarly tiny differences, so small that they were not statistically significant. In plain terms, the two technologies agreed with each other almost perfectly. The researchers calculated a statistical score that measures how closely two sets of data match, and the scores were high, ranging from good to excellent across all measurements. This means that for the basic linear measurements that dentists use to plan surgery, the flat digital X-ray is just as reliable as the expensive 3D scan.

The study did not find that the 3D scan was useless, but it did clarify exactly where its value lies. While the flat X-ray was accurate for measuring height, depth, and width, the 3D scan remains superior for seeing the full three-dimensional shape of a defect, such as whether the bone loss wraps around the tooth or if there are complex walls that a flat image would hide. The researchers concluded that the 3D scan should be reserved for complex cases where that extra detail is absolutely necessary for a treatment decision. For the routine assessment of intrabony defects, the study supports sticking with the digital periapical radiograph. This older, simpler tool offers a practical, cost-effective, and lower-radiation alternative that provides the same accurate measurements for the vast majority of cases. By confirming that the flat X-ray is sufficient for standard linear measurements, the research helps doctors avoid unnecessary radiation exposure and high costs, ensuring that the powerful 3D technology is used only when the situation truly demands it.