Skeletal and dental changes associated with the treatment of deep bite malocclusion.

A retrospective study of 132 treated orthodontic cases presenting at least 70% overbite was conducted using dental casts and lateral cephalometric radiographs from before and after treatment. These were 61 Class I, 27 Class II, Division 1, and 44 Class II, Division 2 malocclusion patients. Six different treatment modalities for the correction of the deep bite were compared. On the basis of the analysis of cephalometric measurements, no statistically significant differences were observed between the various treatment mechanics in the correction of the deep bite. Only in the Class II, Division 2 sample, total anterior face height increased significantly (p < 0.01) with all treatment modalities. The data were then grouped according to Angle classification regardless of the type of mechanics used. Within each Angle class, the changes from before to after treatment were statistically significant for almost all of the cephalometric measurements. These significant changes were due to both anticipated growth and orthodontic treatment. The treatment of overbite primarily affected the proclination of incisors and the extrusion of molars. Within each Angle classification, the patients were also separated according to whether the permanent teeth had been extracted. The nonextraction group was compared with the extraction group for the changes in each cephalometric measurement. It was found that the extraction of teeth did have a significant effect on the changes observed with treatment in all the Angle classes but was more pronounced in the Class I sample. The proclination of incisors was less and the mesial movement of molars was more in patients who were treated with the extraction of premolar teeth than those who were treated with the nonextraction procedures.