ABSTRACT
AIM: The aim of the present study was to evaluate the sagittal and vertical development of the jaws in Class II, Division 1 (II/1) and Class II, Division 2 (II/2) malocclusions. In addition, facial morphology was to be investigated in probands with these malocclusions. PROBANDS AND METHODS: Maxillary and mandibular development was investigated with reference to lateral cephalograms of orthodontically untreated probands from the Belfast Growth Study at 7, 9, 11, 13 and 15 years of age. Moreover, development of facial width was assessed from the associated posteroanterior cephalograms, with radiographic magnifications being corrected in both the lateral and the posteroanterior cephalograms. A Class II/1 group (n = 17) and a Class II/2 group (n = 12) were compared with two control groups: a group with good occlusion (n = 18) and a Class I group (n = 37). RESULTS AND CONCLUSIONS: With respect to the sagittal position of the maxilla, no significant differences between the Class II groups and the controls were found. In the Class II/1 group, mandibular retrognathism was observed. The posterior position of the mandible present at 15 years of age had been present even at 7 years of age, and growth increments in the Class I and Class II/1 subjects were similar. In the Class II/2 groups no uniform pattern with respect to mandibular position was found. With respect to vertical development, a deficit in lower anterior facial height was found in the Class II/2 groups. In addition, between 7 and 15 years of age, growth increments in lower anterior facial height were significantly smaller in the Class II/2 subjects than in the controls. Furthermore, the Class II/2 groups displayed a more euryprosopic facial form on average. The cause of this characteristic facial morphology was the vertical deficit in lower anterior facial height. Overall, however, the broad variability and the small sample sizes, in particular of the Class II/2 groups, in the present study have to be seen as limitations.
