Usefulness of Subtraction Radiography in the Evaluation of Periodontal Therapy

TLDR

Subtraction radiography is a sensitive, accurate method for detecting alveolar crestal changes in periodontal therapy, with about half of radiographs suitable for subtraction analysis using current technology, though it assesses different aspects than probing attachment level. The study evaluated usability by requiring identical interpretation of duplicate subtraction images from radiograph pairs and compared subtraction radiography with bone‑crest height measurements. Subtraction radiography detected changes in 53 % of pairs versus 14 % by crest height, demonstrating greater sensitivity and overall correlation with probing attachment level.

Abstract

Subtraction radiography, a sensitive and accurate technique for identifying alveolar crestal change from standardized pairs of radiographs, is useful in monitoring periodontal therapy. One half of the radiographs were found to be appropriate for subtraction analysis using present technology for taking standardized radiographs. The criterion for usability was identical interpretation of subtraction images made in duplicate from a pair of radiographs. A set of radiographs was analyzed by subtraction radiography as well as by measurement of alveolar bone‐crest height. Subtraction radiography was found to be more sensitive in detecting change. Whereas 53% pairs of radiographs showed a change on subtraction radiography, only 14% showed a change in crest height. Comparison of change by subtraction radiography and probing attachment level showed an overall correlation. Since these two measures assess different aspects of the periodontium, perfect correlation was not expected.