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

Introduction 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.