Orthodontic treatment experience and prevalence of malocclusion traits in an Icelandic adult population.

Background: The objectives of this study were to record the extent of orthodontic treatment and the prevalence of occlusal anomalies in an adult sample in Iceland.

Methods: The study was based on a random sample of 829 subjects, 342 men and 487 women, aged 31 to 44 years, who completed questionnaires about their orthodontic treatment experiences and were available for clinical examination.

Results: Complete dentitions in both jaws were present in 52.8% of the women and 45.3% of the men at the examinations. Significantly higher percentages of the women had received orthodontic treatment of some kind (24.3% compared with 16.9% for the men) and treatment with fixed appliances (16.0% compared with 9.5% for the men). Malocclusion traits were recorded with a standardized method, describing sagittal and vertical incisor relationships, sagittal and transverse molar relationships, and mandibular and maxillary space conditions. The results showed that 45.5% of the subjects had no malocclusions, 33.9% had 1 malocclusion trait, and 20.5% had 2 to 4 traits. The most frequent malocclusion traits were distal molar occlusion (27.7%), mandibular anterior crowding (13.4%), molar crossbite (11.9%), excessive overbite (11.8%), maxillary anterior crowding (7.1%), mesial molar occlusion (6.9%), and excessive overjet (5.3%). The prevalences of mandibular overjet, mesial occlusion, and scissors-bite were significantly higher in the men than in the women.

Conclusions: The prevalences of malocclusion traits were similar in treated and untreated subjects, except for a significantly lower prevalence of overjet and a higher prevalence of molar crossbite in the treated group. Comparison with other studies showed low prevalences of overjet, overbite, open bite, and maxillary and mandibular spacing and crowding; other variables fell within the ranges of prevalence in previous surveys.