Demographic variation of styloid process morphology in panoramic radiography

Elongation of the styloid process (SP) is frequently discussed in the context of Eagle syndrome (ES), with a length threshold of ≥ 30 mm commonly cited as indicative of elongation. However, this criterion is largely derived from heterogeneous imaging modalities and may not adequately account for demographic variability or the projection-related limitations of panoramic radiography. Given that panoramic radiographs (PRs) represent the most common first-line imaging modality in dental and maxillofacial practice, interpretation of SP morphology in this setting warrants critical evaluation. The aim of this study was to characterize demographic variation in SP morphology on standardised PRs and to explore whether commonly cited length thresholds should be interpreted with caution in this imaging modality.

A retrospective analysis of 350 standardised PRs was performed. Bilateral measurements included SP length, width, angulation, distance to anatomical reference points, segmentation according to the Langlais classification, and calcification patterns. Data were stratified by sex and age (≥ 40 vs. <40 years). Statistical comparisons were conducted using Student's t-test and chi-square test (α = 0.05). A post hoc power analysis confirmed adequate statistical power for primary outcome comparisons.

Significant morphological variability was observed across demographic groups. Mean SP lengths exceeded the frequently cited 30 mm threshold in all subgroups. Older individuals demonstrated greater elongation, width, angulation, and advanced calcification patterns compared to younger individuals (p < 0.05). Males exhibited significantly greater linear dimensions than females (p < 0.05). Bilateral elongation was common within the cohort.

SP morphology showed substantial demographic variation on standardised PRs. In this non-symptom-selected cohort, measurements frequently exceeded the commonly cited 30 mm threshold, suggesting that length-based cut-offs should be interpreted cautiously on panoramic imaging. Clinical correlation remains essential, and advanced imaging may be considered in selected cases.