No abstract

The purpose of the study was to describe the craniofacial characteristics of Icelandic adults on lateral skull cephalograms. The material consisted of 155 (47.8%) males and 169 (52.5%) females. The mean ages were 35.5 and 34.2 years, respectively. Twenty-two skeletal reference points and 11 soft tissue points were digitized and processed by standard methods with the Dentofacial Planner computer software program. The 45 variables calculated were both angular and linear. Two-sample t-tests were used to study the differences between sexes. Mandibular prognathism was significantly greater in males (P < or = 0.05), but the inclination of both the upper and lower jaws was greater in females (P < or = 0.01). Linear measurements were usually larger for males. The lips were less protrusive in males (P < or = 0.01), but the thickness was greater compared with females (P < or = 0.001). The nose was significantly more protrusive in males (P < or = 0.001). When the Icelandic sample was compared with closely related ethnic groups, such as the Swedes and the Danes, it was interesting to note that the Icelanders seem to be more like the Swedes than the Danes.

The prevalence of different malocclusion features was investigated in 396 6-year-old Icelandic children, using the epidemiologic registration method described by Björk et al. in 1964. Girls were ahead of boys with regard to dental stage (P < 0.01). One or more permanent teeth were congenitally missing in 5% of the children. Postnormal occlusion was found in 27% of the boys and in 31% of the girls, and prenormal occlusion was found in 6% and 5%, respectively. Straight terminal plane at the second deciduous molars was found in individuals with either normal or postnormal occlusion. Thus, it can be misleading to use the relation of the terminal planes as a measurement of the sagittal relation between the jaws. The prevalence of hypodontia was much lower than has been reported previously for Icelandic children.

The aim of the present study was to describe the craniofacial changes between 6 and 16 years of age in a sample of Icelandic children. Complete sets of lateral cephalometric radiographs were available from 95 males and 87 females. Twenty-two reference points were digitized and processed by standard methods, using the Dentofacial Planner computer software program. Thirty-three angular and linear variables were calculated, including: basal sagittal and vertical measurements, facial ratio, and dental, cranial base and mandibular measurements. For the angular measurements, gender differences were not statistically different for any of the measurements, in either age group, except for the variable s-n-na, which was larger in the 16-year-old boys (P < or = 0.001). Linear variables were consistently larger in the boys compared with the girls at both age levels. During the observation period mandibular prognathism increased but the basal sagittal jaw relationship, the jaw angle, the mandibular plane angle and cranial base flexure (n-s-ba) decreased in both genders (P < or = 0.001). Maxillary prognathism increased only in the boys from 6 to 16 years. Inclination of the lower incisors and all the cranial base dimensions increased in both genders during the observation period. When the Icelandic sample was compared with a similar Norwegian sample, small differences could be noted in the maxillary prognathism, mandibular plane angle and in the inclination of the maxilla. Larger differences were identified in the inclination of the lower incisors. These findings could be used as normative cephalometric standards for 6- and 16-year-old Icelandic children.

The purpose of the study was to describe the craniofacial characteristics of 6-year-old Icelandic children, make a normative standard for children with an Angle Class I molar relationship, and compare them to those with an Angle Class II molar relationship. The material consisted of the radiographs of 363 children, 184 (50.7 per cent) boys and 179 (49.3 per cent) girls with a mean age of 6 years 7 months (range: 5 years 7 months-7 years 8 months). Twenty-two reference points were digitized and processed by standard methods with the Dentofacial Planner computer software program. The 33 variables calculated included both angular and linear. Two sample t-tests were used to study the differences between different groups. Only minimal differences could be noted between sexes in sagittal and vertical angular measurements. Linear measurements, on the other hand, were usually larger for the boys. When compared with Norwegian material of the same age group, similar trends were observed between sexes in both studies, but the Icelandic children showed slightly more mandibular prognathism and a lower mandibular plane angle. When compared with children with an Angle Class I molar relationship, children with an Angle Class II molar relationship did not have a different maxillary prognathism nor a different mandibular length. Cranial base dimensions were all significantly greater and the cranial base flexure was also significantly more obtuse in the distal group.