Comparison of condylar position in hyperdivergent and hypodivergent facial skeletal types.

Orthodontists have long been interested in the differences in the diagnosis and treatment of hyperdivergent and hypodivergent facial types. More recently, many orthodontists have become interested in treating to a seated condylar position or centric relation. It was the objective of this study to investigate the difference in condylar position between these 2 extreme facial types. Two groups of 33 subjects, each representing the extremes in facial type, were randomly selected and matched for age and sex. Mounted casts and the MPI instrumentation were used to measure and compare the amount of condylar distraction between the 2 groups in the horizontal and vertical planes. The total amount of change between the 2 groups was examined using a statistical t-test. There was a statistically significant greater distraction of the condyles in the hyperdivergent group in both the horizontal and vertical planes.