Prediction of rapid palatal expansion success via fractal analysis in hand-wrist radiographs

Abstract

This study aimed to evaluate the efficacy of fractal analysis of hand-wrist radiography in the decision of conventional or surgery-assisted rapid palatal expansion (RPE). The study included 48 patients who underwent the RPE procedure. Study groups were as follows: group 1 (successful conventional RPE [n=24, 5 male and 19 female patients; mean age±standard deviation, 15.85±0.97years]) and group 2 (failed conventional RPE [n=24, 5 male and 19 female patients; mean age±standard deviation, 15.96±1.08years]). Fractal dimension (FD) analysis was conducted on hand-wrist radiographs of the patients for 4 different regions: the epiphysis-diaphysis line of the radius bone and the proximal, medial (MP3), and distal (DP3) phalanxes of the middle finger. A Student t test was performed to compare fractal values between the groups. A receiver operating characteristic analysis was applied to determine the optimal cutoff value of FDs. In addition, a Pearson correlation coefficient was calculated to evaluate the relationship between the fractal values and either age or hand-wrist stage in a second sample group (n=90; age range, 8.7-18.7years). Fractal values of the radius, MP3, and DP3 were significantly increased in the failed conventional RPE group (P<0.05). The optimal cutoff value of the FD for predicting the success of conventional RPE was 1.16 in the radius, 1.18 in proximal phalanxes, 1.29 in MP3, and 1.08 in DP3. There was a positive correlation between fractal values of the radius and age or hand-wrist stages (P<0.05). Within the limits of this study, results revealed that fractal analysis of hand-wrist radiographs might be considered a significant tool in the prediction of RPE success.