CBCT assessment of posterior cranial base and surrounding structures in orthodontically treated adolescents.

Objective: Understanding craniofacial growth and development is important for accurate diagnosis, treatment planning and post-treatment evaluation of orthodontic cases. Paramount to this is knowledge of the cranial base growth and development, since it is the foundation upon which the remaining facial structures develop. The purpose of this study was to analyse different anatomical structures in the posterior cranial base and determine its changes during the adolescent years (13-15 year of age) using CBCT.

Materials And Methods: Sixty CBCT images of the adolescent population that received orthodontic treatment at two time-points (mean age T1: 13.1 years/T2: 14.6years) were used to assess growth related dimensional changes using 33 selected landmarks. Inter-rater, intra-rater and accuracy of 33 selected landmarks in the posterior cranial base and surrounding area were then evaluated via three-dimensional (3D) cone-beam computed tomography (CBCT). Linear differences were then calculated among the different landmarks to determine the changes present in the sample.

Results: The selected landmarks in the posterior cranial base and surrounding area were found to be reliably and accurately located in 3D. Over the growth period studied (17.5months), minor statistically significant changes occurred, but they were deemed clinically irrelevant.

Conclusions: The studied landmarks in the posterior cranial base and surrounding area showed minor clinically insignificant changes over the study period. The observed changes could be attributed to measurement error. The posterior cranial base is deemed to be stable in all three dimensions of study during the adolescent growth period studied.