A COMPARISON OF 2 PATIENT POPULATIONS USING FRACTAL ANALYSIS

THIS STUDY WAS UNDERTAKEN TO DEMONSTRATE that the fractal dimensions c alculated using digitized non-standardized, clinical radiographs of ma ndibular alveolar bone from a population of patients diagnosed with pe riodontitis are statistically different from fractal dimensions calcul ated from another population diagnosed as having gingivitis or healthy gingiva. The fractal dimension was calculated using a public domain f ractal analysis program distributed by the National Institutes of Heal th (NM). Fractal dimensions were calculated from digitized clinical ra diographs for 29 patients diagnosed with healthy gingiva and/or gingiv itis and 32 patients diagnosed with periodontitis and compared. To est imate the reproducibility of the technique, we recalculated the fracta l dimension from images of the gingivitis patients 3 months after the original calculations and compared them to the originals. A 2 sample, 2-tailed Student t test showed the gingivitis data group to be differe nt from the periodontitis data group (P = 0.0012). The original gingiv itis and repeat gingivitis groups fractal dimension calculation were t he same and analysis showed the two data sets were not significantly d ifferent (P = 0.99). We found that: 1) fractal dimensions could be use d to distinguish between gingivitis and periodontitis patient groups; 2) fractal dimensions could be calculated from non-standardized clinic al radiographs; and 3) fractal dimensions for gingivitis patients were reproducible over a 3-month period.