Assessment of periodontal bone loss with film and digital images

Objectives: This study aimed to compare clinicians’ ability to assess alveolar bone loss and furcation involvement using conventional and digital radiographic techniques. Methods: Six clinicians studied images of 23 upper and 40 lower molars with alveolar bone loss in dry skulls. Standardised images were taken using conventional F speed double film packages, into which photostimulable phosphor plates were inserted. Direct skull measurements were gold standard. Digital images were viewed without and following image manipulations. Images were repeated to assess reproducibility. Results: Reproducibility of bone height assessment was good (intraclass correlation 0.70 to 0.98, 10 pairs) and poor for buccal furcations (kappa –0.02 to 0.46, 8 pairs) for conventional and digital images. Neither method scored consistently greater or lesser vertical bone loss, but 3 of 6 clinicians underestimated this with conventional film (t-test, p=0.035 to 0.001). T-test indicated variable accuracy of assessment of bone loss for digital versus conventional images when compared to gold standard. Kappa scores indicated highly variable but generally zero or poor agreement with gold standard for assessment of buccal (-0.08 to 0.05, n=58) mesial (-0.15 to 0.43, n=6) and distal (-0.21 to 0.40, n=12) furcations. Lower molar buccal furcations showed better correlation with gold standard (0.15 to 0.48, n=40) than upper (-0.20 to 0.11, n=23), and for lower furcations, digital imaging generally gave better agreement than conventional film (0.30 to 0.48 versus 0.15 to 0.49). Conclusions: Digital imaging gave no greater accuracy of furcation assessment by clinicians, except at lower molar furcations. Their use may be more precise than conventional film for assessing bone levels.