Fractal analysis for the assessment of trabecular peri-implant alveolar bone using panoramic radiographs

There is no consensus on the relationship between fractal dimension and trabecular bone complexity. Our aims were to examine the changes in fractal dimension (FD) from peri-implant alveolar bone on digital panoramic radiographs 6 and 12 months after prosthodontic loading and to compare these with baseline values calculated just after loading. Three panoramic radiographs taken from 76 implant patients taken (1) after prosthodontic loading (3 months +/- 2 weeks after insertion = baseline), (2) 6 months +/- 2 weeks after loading, and (3) 12 months +/- 2 weeks after loading were considered for the study. Panoramic images were obtained using storage phosphor plates of the Digora PCT system and saved into a computer. Three regions of interest from mesial, distal, and apical areas were selected for each implant on three consecutive panoramic images. Statistical analysis of the data was performed using two-way repeated measures ANOVA, independent t test and paired t test, and pairwise comparisons (P < 0.05). Mean FD values at baseline were 1.202, 1.224, and 1.199 for apical, mesial, and distal areas. The FD values were calculated as 1.121, 1.113, and 1.128 at the 6th month. The differences between values calculated at baseline and the 6th month were statistically significant for all aspects, indicating a significant decrease in FD 6 months after prosthodontic loading (P < 0.05). FD values calculated at the 12th month were 1.121, 1.110, and 1.121 for apical, mesial, and distal aspects, respectively, with no significant differences from corresponding values obtained at the 6th month (P > 0.05). FD values of trabecular bone around implants 6 months after prosthodontic loading are significantly lower than the baseline values. However, no significant decrease or increase was observed at 12 months, which revealed comparable results with peri-implant alveolar bone at 6 months. Trabecular bone around successful dental implants exhibits lower fractal dimension values 6 months after prosthodontic loading and displays stable bony microstructure at 12 months of follow-up.