During the last three decades there has been an increased influx of refugees and immigrants into Scandinavia. The overall aim of this thesis was primarily to improve our knowledge of malocclusion and orthodontic treatment need, both normative and self-perceived, in adolescents of varying geographic origin. A further aim was to determine whether any differences with respect to perception of general appearance and psychosocial well-being were related to geographic origin.

Papers I and II concerned self perceived and normative orthodontic treatment need. About 500 12-13 year-old subjects, stratified into different groups: A-Sweden, B-Eastern/Southeastern Europe, C-Asia and D-other countries, answered a questionnaire and underwent clinical examination by the author. In paper III the association between the two variables in papers I and II was investigated. Paper IV was a follow up study, at 18-19 years of age, of the relationship between geographic origin and prevalence of malocclusion, self-perceived treatment need, temporomandibular symptoms and psychosocial wellbeing. In Paper V a qualitative study of 19-20 year old subjects was conducted, to identify the strategies they had adopted to handle the issue of persisting poor dental aesthetics.

The main findings were that at 12-13 years of age, immigrant subjects had a lower perceived orthodontic treatment need than subjects of Swedish background. Girls of Swedish background had the highest self perceived treatment need, whilst girls of non-Swedish background were most concerned that fixed appliance therapy would be painful. In a few of the clinical variables measured at 12-13 years of age, the Swedish group exhibited the greatest space deficiency and irregularity in both the maxillary and mandibular anterior segments and greater overjet, compared to the Eastern/Southeastern European and Asian groups. The clinical implications were negligible. The orthodontic treatment need according to “Index of Orthodontic Treatment Need - Dental HealthComponent” (IOTN-DHC) grades 4 and 5, ranged from 30 to 40 percent, without any inter-group differences. There were strong associations between subjects perceiving a need for orthodontic treatment and 6IOTN-DHC grades 4 and 5, anterior crossbite and avoiding smiling because they were self-conscious about their teeth. At the age of 18-19 years, the frequency of malocclusion was similar in all groups. Subjects of Asian origin had a higher self-perceived orthodontic treatment need than their Swedish counterparts and a higher frequency of headache than those of Eastern/Southeastern European origin. Psychological wellbeing was reduced in nearly one quarter of the sample, more frequently in girls than boys. No association was found between self-perceived orthodontic treatment need and psychological wellbeing.

The theory “Being under the pressure of social norms” was generated in Paper V, and it can be applied to improve our understanding of young adults who have adjusted to living with poor dental aesthetics and also aid to identify those who are not as well-adjusted and would probably benefit from treatment. Undisclosed dental fear is an important barrier to acceptance of orthodontic treatment in early adolescence. Despite demographic changes due to immigration, no major change in the prevalence of malocclusion and normative orthodontic treatment need has been disclosed. This does not apply to adolescents and adults who immigrated at an older age.