Relationship Between Styloid Process Size and the Skeletal Craniofacial Pattern: A Cross-Sectional Study

Objective: The purpose of this correlation study was to evaluate a possible association between the styloid process size and different craniofacial skeletal patterns, in the sagittal and the vertical planes. Methods: 59 consecutive orthodontic adult patients were selected. The styloid process length was measured on pretreatment panoramic radiographs and the cephalometric skeletal variables on lateral cephalometric radiographs. Data were analyzed using independent sample T-Tests, Mann-Whitney U Tests and Spearman´s partial correlations (?=5%). Results: Males exhibited longer styloid processes than females (p=0.029), with a mean difference of 7.5mm. Within each individual, right and left styloid process length was similar (r= 0.77; p<0.001). No relationship was found between the size of the styloid process and the sagittal skeletal pattern. A moderate significant correlation was present between the size of the styloid process and some vertical cephalometric skeletal variables: Ar-Go-Me (r=0.32; p=0.02), PFH/AFH (r=-0.29; p=0.03) and MP-SN (r=0.28; p=0.03). Conclusion: Longer styloid processes tend to be associated with high angle skeletal patterns. Orthodontists, general dentists and oral surgeons should be aware that elongation of the styloid process is more frequently verified in hyperdivergent individuals.