Assessment the Effect of Exposure Conditions and Geometry Parameters on Calculated Fractal Dimension of Mandibular Bone

One of the fractal analysis methods to examine the structure of a texture is fractal dimension (F.D.) measurement. F.D is a quantitative method to show the complexity of a structure using a number. The aim of this study was to determine the effect of different exposure conditions, voltages and angle of x-ray tube on F.D. values of mandibular bone.

This lab-trial analytical research was conducted on ten healthy, non-fracturing human mandibles. Periapical digital images were obtained by the Peri-Apical Focus (Planmeca, Finland) with a constant time of 0.2 seconds and changes in exposure conditions and angle of the tube. Periapical radiographs were obtained with 2 kV voltages of 60, 70, with2 mA of 400, 500, and 3 tube angles of -5, 0, +5 degrees. Data was analyzed by SPSS version 16 software  and Kolmogorov–Smirnov test, mann whitney testand ANOVA test.

No significant difference was observed in fractal mean values between 60 and 70 kVp and among 5-, 0, 5+ degrees in all 10 mandibles.There was a significant difference between the 400 and 500 mA just in one case (p≤0.05).

Considering the incompatibility of the amount of calculated fractal dimension from kVp, mA and tube angle, this method can be used as a useful tool in dentistry to examine the structure of spongy bone and its changes in various pathological conditions. Then, standardize the periapical imaging technique to compare it is not necessary.