Transverse dental and dental arch depth dimensions in the mixed dentition in a skeletal sample from the 14th to the 19th century and Norwegian children and Norwegian Sami children of today.

Secular changes in transverse dental arch dimensions and dental arch depth were studied. Four cohorts with mixed dentitions were selected. The skull group comprised 48 skulls dating from the 14th to the 19th century and belonging to The Schreiner Collection at the Department of Anatomy, University of Oslo. The 1980s Sami group was comprised of 39 boys and 34 girls born in 1987 and living in the northern part of Norway. The 1960s Oslo group was comprised of 31 boys and 30 girls born in 1963 and living in the southern part of Norway. The 1980s Oslo group was comprised of 32 boys and 26 girls born in 1983 and living in the same area in southern Norway as the previous Oslo group. Sex was unknown in the skeletal sample, and the groups were analyzed with the sexes pooled; separate descriptive values are presented for the modern groups. The mandibular intercanine distance was smaller in the skulls compared with the modern groups. The transverse intermaxillary difference between the molars was larger in the skull group than in the 1980s Oslo group. The difference between the maxillary and mandibular intercanine distances was larger in the skulls compared with the modern groups, although the small number of measurements in the skull group impeded further analysis. The arch depth was smaller in the skull group compared with the modern groups; the 1960s Oslo group deviated because of a higher prevalence of caries in the second deciduous molars. The overjet was smaller among the skulls. The arch form measured as the angle between the left and right molar tooth rows was more acute in the skulls than in the modern groups. It was concluded that smaller arch depths are found in skeletal samples at early ages and that attrition does not explain the more upright incisors found in skeletal samples. A secular trend was found in the intermaxillary relation, which indicated that children in the 1980s Oslo group were at greater risk of developing a posterior cross-bite than children born in the 14th to 19th centuries.