Skeletal and Dental Relationships in Vertical/Non-vertical Growers Using CBCT

Objectives: The purpose of this study was to determine if there were any common skeletal and dental structural characteristics obtained from cone-beam computed tomography images (CBCTs) of patients with different growth patterns (Vertical or Non-Vertical).
Methods: Sixty-three patients were previously categorized as vertical or not vertical grower using clinical examination and 2D cephalometric created images from their respective CBCTs. Twenty-three landmarks were selected (based on traditional and newly suggested landmarks) to examine CBCT images obtained from the University of Alberta Graduate Orthodontic program using the AVIZO software. Reliability and measurement error was tested by analyzing ten images three times using intraclass correlation coefficient (ICC). All CBCT images were then analyzed and the landmark coordinates were used to calculate linear and angle measurements using geometric and trigonometric equations. Statistical analysis was done using SPSS statistical package.
Results: ICC values showed excellent reliability as all twenty-three landmarks were above 0.97 in all axis. The largest measurement error was 1.62mm +- 0.68 found in the y-axis for the Right Anterior Concavity point. All linear and angular measurements did not present a statistical significant difference between both growth groups. The Left Anterior Facial Height (A point -B point) showed the greatest difference between the groups; the vertical group was 39.0mm +- 3.9 while the non-vertical group was 35.2mm +- 4.4. The symphysis thickness (POG – Z point) also showed one of the largest differences; the vertical group was 23.3 mm +- 3.2 while the non vertical group was 21.1mm +- 2.9.
Conclusions: The calculated linear and angular measurements were not statistically or clinically different between vertical and non-vertical growers. This indicates that other methods may need to be used to determine if a patient is a vertical or non-vertical grower.