Introduction: The purpose of this study was to examine longitudinally the development of specific occlusal traits and space conditions in an Icelandic sample.
Methods: The sample comprised 245 adolescents examined clinically in the late mixed or permanent dentition and again 25 years later. All subjects were orthodontically untreated, and all had the full complement of teeth at both examinations.
Results: A significant increase in the prevalence of mandibular anterior crowding and mesial molar relationships and a decrease in the prevalence of excessive overjet and maxillary anterior spacing were seen. The persistence of malocclusion traits ranged from 17.9% to 53.4% for maxillary anterior spacing and crowding, mandibular spacing, overjet, overbite, and distal molar occlusion, whereas anterior mandibular crowding and molar crossbite were still found in 72.7% and 75.0%, respectively, at the second examination. Normal occlusal traits and space conditions at adolescence stayed mostly unchanged, with the exception of 11.2% of the subjects, who developed mandibular anterior crowding between the first and second examinations.
Conclusions: Deterioration of normal occlusal traits and space relationships was uncommon in this study, whereas self-correction of malocclusion traits and space anomalies was relatively frequent.