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The methodology for the use of subtraction radiography in the study of human periodontal disease is described in detail to include: 1) design and fabrication of a system for taking standardized radiographs; 2) generation of interpretable subtraction images; 3) adjunctive, quantitative methods for analyses of digitized radiographic images; 4) reference standard for periodontally healthy individuals. Correct use of our system for taking standardized radiographs can provide a sufficient number of pairs of radiographs for the study of patients with severe periodontitis using subtraction radiography. Changes in bone mass observed on subtraction images can be quantified by measurement of their areas and their relationship to the alveolar crest. [ABSTRACT FROM AUTHOR]

Crestal interdental bone in 15 untreated subjects with periodontitis was monitored over a 6-month period. Whereas 9% of interdental sites exhibited bone loss, 4% exhibited bone gain. The sites of bone loss were found in 9 of the subjects. 2 subjects demonstrated gain as well as loss, with 1 subject demonstrating only gain Pocket depth, gingival index and plaque index values were of little value in predicting bone change seen by subtraction. Results from subtraction radiography are consistent with exacerbation and remission at crestal alveolar bone sites in untreated periodontitis patients. [ABSTRACT FROM AUTHOR]

A standardized radiographic series of incrementally increasing alveolar crestal defects in skulls were subjected to analyses by subtraction radiography and computer assisted quantitative densitometric analysis. Subjects were able to detect change using subtraction radiography in alveolar bone defects with bone loss in the range of 1-5 percent as measured by 125I absorptiometry. Quantitative densitometric analyses utilizing radiographic pairs adjusted for differences in contrast (gamma corrected) can be used to follow longitudinal changes at a particular alveolar bone site. Such measurements correlate with change observed by 125 absorptiometry (r = 0.82-0.94). [ABSTRACT FROM AUTHOR]