Occlusal characteristics in groups of Tanzanian and Finnish urban schoolchildren.

The occurrence of different occlusal and space anomalies was studied in groups of 642 Tanzanian and 458 Finnish school-children. Similar diagnostic criteria and methods were used in both countries. The Finnish children had significantly higher prevalences of distal occlusion and crowding and a lower prevalence of anterior openbite than the Tanzanian children. The proportion of subjects with no occlusal or space anomalies was considerably higher among the Tanzanians than among the Finns, 55% and 12% to 22%, respectively. The distinct differences found in occlusion of Tanzanian and Finnish children in this study seem to reflect differences in hereditary or environmental factors, which are expressed as craniofacial or dentoalveolar differences between these ethnic groups.