Incisor position in Scandinavian children with ideal occlusion. A comparison with the Ricketts and Steiner standards

A cephalometric study, with particular emphasis on incisor pattern, was carried out on thirty Norwegian children with clinically excellent occlusion in the young permanent dentition. The material was selected from a sample of all 12-year-old children within a particular geographic area (Nittedal) of Oslo. The frequency of ideal occlusion was 5.3 percent. A computer-based method of cephalometric analysis was used. The findings indicated that persons with untreated ideal occlusion tended to have a particular facial morphology and dental pattern. More precisely, they were likely to be brachyfacial (horizontal), with somewhat procumbent incisors and a small interincisal angle. Only one patient had dolichofacial (high-angle) characteristics. On average, the lower incisors were 2.5 mm. in front of the APo plane (S.D. 1.7). Remarkably, the lower incisors were not behind the APo plane in any single case with ideal occlusion. Clearly, the lower incisors were clinically significantly more protruded and proclined than those described in previous studies on Scandinavian children and were, in fact, even slightly more procumbent than the Ricketts and Steiner standards. The similarity, with regard to both incisor position and skeletal pattern, of the present findings to some recent studies on American Caucasian children with normal occlusion is stressed. The significance of the observations is discussed in relationship to considerations in orthodontic treatment planning.