Introduction: Clinicians have long been interested in the multitude of differences in the diagnosis, treatment, and the treatment response between the hyperdivergent or dolicofacial types and hypodivergent or brachyfacial types.
Since its introduction by Broadbent in 1931, the cephalometric radiograph is used as the golden standard in orthodontic diagnosis and treatment planning. Many analyses have been created by which to compare skeletal and dental relationships.
Lateral cephalometry is an important tool in orthodontic diagnosis of the vertical jaw relationships, treatment planning, prediction of growth and the evaluation of these different facial forms. Little research has been undertaken to evaluate how valuable an orthopantomograph radiograph is in diagnosing and treatment planning orthodontic patients with regard to facial types.
Purpose: The aim of this study was to evaluate the use of the measurements taken from the orthopantomograph as compared to that of the lateral cephalogram for investigating the vertical jaw relationship patterns of individuals.
Materials and Methods: The sample size consisted of ninety patients, equally divided into the three different growth patterns namely dolicofacial, mesofacial and brachyfacial. Lateral cephalograms and orthopantomographs of these patients were compared
The patients were categorized as vertical, normal and horizontal. The cephalogram was used as the gold standard for the three different categories
The gonial angle which is the angle between the tangents of the inferior border and posterior border of the mandible was measured on the lateral cephalogram and the orthopantomograph. The upper and lower facial heights was measured on the lateral cephalogram, as well as the Y axis. The condyle angle which is an angle formed at the intersection of the ramus height and a line parallel to the posterior tangent line was measured on both the orthopantomograph and the lateral cephalogram. The ramus height was also measured on both the lateral cephalogram and orthopantomograph.
Results: Comparisons were made of the mean and standard deviation and the median values from the gonial angle, the ramus height and the condyle angle, measured for the three different growth types. With respect to the normal growth pattern and the horizontal growth pattern the mean and median for the gonial and the condyle angles, there was no significant difference. However there was a significant difference in the mean and median values for the ramus height.
The results were different for the vertical patient. The mean and median values for both the gonial angle and the ramus height differed significantly for the two radiographs. While the mean and median values for the condyle angle did not differ significantly.
The results with respect to the correlations showed significant correlations between the gonial angle and the condyle angle for all three growth patterns. However this was not the case for the ramus height.
Conclusion: Based on these findings it can be concluded that angular measurements could be correlated between the two radiographs. There is however, little consistency between the linear measurements taken from an orthopantomograph and that of a lateral cephalogram.
Dissertation (MScDent)--University of Pretoria, 2015.