Pilot study: digital subtraction radiography as a tool to assess alveolar bone changes in periodontitis patients under treatment with subantimicrobial doses of doxycycline

Background: Subtle changes in marginal alveolar bone level can be demonstrated using digital subtraction of sequential radiographs. Objective: We aimed to evaluate the practical application of geometrically corrected digital subtraction in a clinical study of alveolar bone response to a drug previously shown to inhibit alveolar bone loss. Study design: Selected periapical radiographs were acquired with projective standardization of patients with clinical marginal alveolar bone loss. Subsequently, patients received a 6-month regimen of subantimicrobial doxycycline or placebo. Standardized radiographs of the same alveolar regions were acquired after 3 and 6 months, and baseline radiographs were subtracted from these images. Results: Blinded digital subtraction analysis indicated various levels of marginal bone gain in 3 of the 6 patients in the experimental group, whereas in 3 of the 5 placebo patients the method showed bone loss. Conclusion: These results suggest that geometrically corrected digital subtraction possibly agrees with clinical predictors of bone loss severity.