Abstract

The craniofacial morphology of children with Class II-1 malocclusion with and without deepbite was studied and compared with that of a control group of children with normal occlusion. Common for the Class II-1 children was a short mandibular corpus, which was probably the main reason these children had a distal basal jaw relationship.

The Class II children with deepbite differed from the control group in ways. They had: 1) a distal relationship between points A and B; 2) a distal relationship between points A and pogonion; and 3) a discrepancy in length between the corpora of the two jaws. These deviations discriminated nearly 95% correct between the deepbite group and the controls.

The most characteristic deviations in the Class II children without deepbite, in relation to the controls, were: 1) a distal relationship between points A and B; 2) a small angle between the nasal plane and the anterior cranial base; and 3) a long mental process. These deviations discriminated about 95% correct between the experimental group and the controls.

Many of the craniofacial differences between the Class II groups could, theoretically, be explained by the MP-SN angle being, on average, 9 degrees larger in the children without deepbite. Most typical was that this group has 1) a larger lower anterior face height, 2) larger maxillary and mandibular incisal heights, and 3) a more obvious distal relationship between points A and pogonion. In combination, these differences discriminated correctly between the Class II groups in 90% to 97% of the cases.