Dental arch dimensions in Class II division 1 malocclusions with mandibular deficiency.

OBJECTIVE

To test the hypothesis that there is no difference in the dimensions of the upper and lower dental arches in Class II division 1 malocclusion with a mandibular deficiency compared to normal Class I occlusion dental arches.

MATERIALS AND METHODS

Photocopies of the dental arches of 48 patients exhibiting Class II division 1 malocclusion with mandibular deficiency and of 51 individuals with normal occlusion were compared. Mandibular deficiency was diagnosed clinically. All 99 individuals were in the permanent dentition. The ages of the subjects ranged from 11 years 4 months to 20 years (mean age = 12 years 5 months).

RESULTS

When compared to subjects with normal occlusion, the upper dental arches of the Class II division 1 patients presented reduced transverse dimensions and longer sagittal dimensions while the lower arches were less influenced.

CONCLUSION

The hypothesis is rejected. Significant differences are present between the dimensions of the upper and lower dental arches in Class II division 1 malocclusion (with a mandibular deficiency and in the permanent dentition) compared to normal Class I occlusion dental arches.