Fractal analysis and assessment of lacunarity in mandibular osteoradionecrosis: a cross-sectional study with control group.

The objective of this study was to evaluate the fractal dimension (FD) and lacunarity of the mandibular bone, comparing patients with and without osteoradionecrosis (ORN). In a cross-sectional study with a control group, 25 patients were included and divided into a case group (with ORN, n = 14) and a control group (without ORN, n = 11). A digital panoramic radiograph taken after the end of radiotherapy (RT) was evaluated for each patient. FD and lacunarity of the mandibular bone were determined using ImageJ software. Descriptive, bivariate, and ROC curve analyses were performed. Cohen's d effect sizes were calculated. Significance was established at p < 0.05. The mean FD and lacunarity values were not significantly different between the groups. The area under the curve for FD and lacunarity were 0.579 and 0.661, respectively. The cut-off point for FD was ≤1.1714 and for lacunarity, > 0.3821, correctly classifying the majority of cases and controls. Most participants in the case group (63.6%) had a FD ≤ 1.1714 and the majority of participants in the control group (63.6%) had a FD >1.1714 (p = 0.395). For lacunarity, most individuals in the case group (72.7%) had a value > 0.3821 and most participants in the control group (63.6%) had a value ≤ 0.3821 (p = 0.198). In conclusion, the FD and lacunarity values did not show statistically significant differences between patients with and without ORN. However, the moderate and large magnitude of the effects seem to indicate that the results may be clinically relevant.