Background. Chemotherapy, one of the most important treatment modalities for treating childhood cancers, is a major cause of bone loss in patients and survivors.Objectives.This study aimed to evaluate mandibular bone structures in childhood cancer survivors (CCSs) by means of fractal dimension (FD) analysis and the Klemetti index (KI), and to compare them with regard to the control group.Material and methods. In this retrospective study, the panoramic radiographs of 49 CCSs were included as the study group and the panoramic radiographs of 49 cancer-free volunteers were included as the control group. Based on the panoramic radiographs, FD and KI were determined.Results. No significant differences were observed between the study and control groups in terms of mean FD values for regions of interest (ROIs) ROI_1, ROI_2 and ROI_3 (p = 0.750, p = 0.490 and p = 0.910, respectively). The mean FD values for ROI_1 for the study and control groups were 1.08 +/- 0.18 and 1.07 +/- 0.14, respectively. The mean FD values for ROI_2 for the study and control groups were 1.11 +/- 0.13 and 1.09 +/- 0.13, respectively. The mean FD values for ROI_3 for the study and control groups were 1.15 +/- 0.14 and 1.15 +/- 0.15, respectively. Statistically significant differences between the study and control groups were noted only in the distribution of the KI categories (p = 0.015).Conclusions. Childhood chemotherapy may affect mandibular bone structures during a lifetime. The Klemetti index should be considered a useful clinical diagnostic tool for the examination of mandibular bone structures.