Measurements and TMJ Bone Changes in CBCT and Skulls

Objectives: To evaluate the type of bone changes of TMJ (temporomandibular joint) directly in the bone in comparison to CBCT (cone beam computed tomography).
Methods: Sixty-two skulls from the University of Pittsburgh, School of Dental Medicine collection were used as part of this study. Each skull was scanned using CBCT. Using a blinded examiner, the bone changes in the images were classified as apparently normal, or with erosion, roughening, flattening, or deformation. The same classification was used in the real skulls. Measurements with the condyles in lateral and coronal views were performed in both the CBCT and the real skulls. Student t test was used to assess differences in the measurements in the images in comparison to directly in the skulls (alpha = 0.05).
Results: There were significant differences in the length of the left and right condyles when comparing CBCT and real skulls. For the coronal view, the CBCT results were smaller but not statistically significant different for both right (0 = 0.196) and left condyles (p = 0.397) compared to the real skulls. For the lateral view, the CBCT results were bigger for both right (p = 0.042) and left condyles (p = 0.002) compared to the real skulls. For both left and right condyles, osteophyte was the most observed bone change in both CBCT and real skulls.
Conclusions: This study illustrates that there are differences in measurements obtained in the CBCT in regards to the actual anatomical structures of the TMJ. Osteophyte is visibly detected in CBCT and real skulls despite in the real skull it is measured in 3-D, whereas in the CBCT it is measured by observing the right and left condyles in coronal and lateral views.