Vertical changes in treated and untreated Class II division 1 malocclusions.

Background: Treatment-induced increases in the height of the face may be permanent.

Aims: To determine if appliance-induced increases in the heights of the upper and lower molars in girls with Class II division 1 malocclusion, and the consequential increase in the height of the face are maintained.

Methods: Ten angles and 10 distances were measured on lateral cephalometric radiographs of 11 year-old girls (Range: 8.5-14.8 years) with treated (N = 9) and untreated (N = 8) Class II division 1 malocclusions. The intervals between the initial and recall records were, on average, 12 years (Range: 7.6-15.7 years) for the girls in the treatment group, and 8 years (Range: 4-13 years) for the girls in the untreated/control group. In the treatment group eight girls were treated with the Begg appliance and Class II elastics.

Results: Upper and lower molar dentoalveolar heights in both groups increased significantly between the initial and recall visits. There were no significant differences between the molar heights in the groups at the start or at recall. Anterior face height (AFH) also increased significantly in both groups between the initial and recall visits. At recall, AFH in the treatment group was significantly greater than AFH in the control group. This finding is attributed to a similar-sized difference between the groups at the start, to the longer period between the initial and recall records in the treatment group and to lesser variation in both groups at recall. In both groups, posterior face height increased significantly between the initial and recall stages. At the conclusion of the study there were no statistically significant differences between the treated and control groups in either overjet or the inclination of the upper incisors. Relapse of the upper incisors in the treatment group and retroclination of the upper incisors in the control group reduced the initial differences between the groups. These changes are attributed to altered lip posture and increased lip pressures in adolescence. At recall, angles SNA and SNB were significantly smaller in the treatment group.

Conclusion: The heights of the upper and lower molars and the face increased in both groups. Orthodontic treatment may have no lasting effects on either the height of the face or the heights of the molars in girls with Class II division 1 malocclusion.