Related Experiment Video
Updated: May 28, 2026
Midface Hypoplasia and Cranial Base Morphology in Syndromic Craniosynostosis: A Comparative Analysis Study Using a Predictive Regression Model
Published on: November 4, 2025
Quantitative insights into cranial fusion: fractal dimension analysis of spheno-occipital synchondrosis
Fatemeh Akbarizadeh1, Kiarash Fereidouni2, Shakiba Benvari3
1Orthodontic Research Center, School of Dentistry, Shiraz University of Medial Science, Shiraz, Islamic Republic of Iran.
Objective:
Chronological age is not always a reliable indicator of skeletal maturity. The Spheno-Occipital Synchondrosis (SOS), a key growth center of the cranial base, has been qualitatively linked to age. This study introduces fractal dimension (FD), a quantitative metric derived from fractal analysis (FA), to assess SOS fusion and its correlation with age using cone beam computed tomography (CBCT) images.
Methods:
In this retrospective cross-sectional study, 102 CBCT scans (ages 6-22) were analyzed. SOS fusion stages were classified qualitatively and evaluated quantitatively via FD using ImageJ software. Inter- and intra-observer reliability, correlation between FD and age, and diagnostic performance via ROC analysis were assessed.
Results:
FD significantly declined with age (males: r = -0.66; females: r = -0.80; p < 0.001). FD differed significantly across SOS fusion stages and age groups (p < 0.001), with gender-specific patterns in intermediate stages. Regression analysis demonstrated FD as a significant age predictor (R² = 0.44 for males, R² = 0.64 for females). ROC analysis showed excellent-to-outstanding diagnostic accuracy (AUC: 0.815 for males; 0.945 for females) in distinguishing legal age thresholds.
Conclusion:
Fractal dimension analysis of the SOS on CBCT offers a reliable, reproducible, and objective method for age estimation. FD provides quantifiable insight into cranial base maturation, supporting its application in orthodontic planning and forensic age assessment.
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