Elongated styloid process in patients with temporomandibular disorders - Is there a link?

BACKGROUND: Elongated styloid processes may display clinical signs that can easily be confused with symptoms associated with temporomandibular disorders (TMD). Thus, the present study aimed to investigate alterations of the styloid process in patients with TMD.

METHODS: Temporomandibular joint (TMJ) X-ray images of 192 patients with RDC/TMD diagnoses were examined retrospectively. On each side, the styloid process and mandibular ramus were evaluated regarding length as well as sagittal angulation. Data were statistically analyzed using two-way ANOVA, Pearson's r and Kruskal-Wallis test. In order to confirm the accuracy of the obtained X-ray measurements, the available cone-beam-computed tomographies (CBCT) of the subjects were also examined as reference standard and compared with the X-ray TMJ data by using Bland-Altman analysis.

RESULTS: In a group of TMD patients we assessed a mean styloid length of 40.8mm over both genders. In female subjects the means of length and angulation of the styloid process were 40.4mm and 54.9°, male subjects showed means of 42.1mm and 63.4°. The mean height of the mandibular ramus in males was significantly higher than the same measurement in females (66.8mm vs 59.7mm). Styloid length in relation to ramus height (relative styloid length) was significantly larger in females. No significant correlations between RDC/TMD diagnoses and process length as well as process angle were found. A Bland-Altman analysis revealed conformity of CBCT and digital X-ray results.

CONCLUSION: The mean styloid length measured in a group of TMD patients is referred to as elongated, whereas females showed longer styloid in relation to body height. However, it appears that alterations of the styloid are not related to TMD diagnoses.