Background: The aim of the study was to describe prevalence, severity and distribution of periodontal disease as well as associated risk factors in an indigenous Sámi population in Northern Norway, and to investigate differences between the indigenous Sámi and the non-Sámi population. Methods: This cross-sectional study included data from the Dental Health in the North study (N = 2078; 18-75 years). Data on Ethnicity, household income, education, smoking habits, dental attendance, and tooth brushing habits were collected by a questionnaire. Periodontal conditions were assessed by clinical examination. A modified version of the new AAP/EFP classification system of periodontal disease was used to estimate the severity of periodontitis. Three stages were used: 'Non-severe periodontitis', 'Stage II', and stage 'III/IV'. Results: Of the total study population 66.5% reported Sámi affiliation. The total prevalence of periodontitis was 49.7%, with 20.1% in Stage III/IV, but no differences between Sámi and non-Sámi. When controlled for sex, age, education, smoking and dental attendance the Sámi had higher probability of having more severe stages of periodontitis; Odds Ratio Stage II (OR) = 1.3; 95% CI: 1.1-1.7; and OR Stage III/IV (OR) = 1.6; 95% CI: 1.1-2.2) compared to non-Sámi. The Sámi had higher prevalence of periodontal pocket depth (PD) ≥ 4 mm (t = 1.77; p < 0.001) and PD ≥ 6 mm (t = 1.08; p = 0.038) than the non-Sámi. Conclusions: The prevalence of periodontitis was high in communities in the core area of Sámi settlement in Northern Norway, regardless of ethnicity. People with Sámi ethnicity had more deep periodontal pockets and an increased odds of having severe stages of periodontitis. Future studies should address possible explaining factors behind the potential higher risk of having more severe periodontitis among indigenous people in Sámi settlements.

Objective: This study aims at presenting the feasibility of using the public oral health clinics in indigenous S ami communities, as arena for a comprehensive data collection for population-based epidemiological oral health research among adults (age, 18-75 years) in a multi-ethnic setting. Material and methods: The study design was cross-sectional. The data collection was incorporated into the clinical procedure at six public dental clinics situated in the Administrative Area for the S ami Language in Finnmark County, Northern Norway, during 2013-2014. Both clinical-and questionnairedata were collected. The quality of clinical data was thoroughly calibrated and validated. Results: Altogether, 2235 people participated in the study gave a crude response rate at 88.7%. In the final data sample (n ¼ 2034), 56.9% were female. We constructed three ethnic groups (S ami, Mixed S ami/Norwegian and Norwegian). Altogether, 67.7% reported S ami or mixed S ami ethnicity. The internal validity of the clinical data was found to be satisfactory when assessed by comprehensive quality procedure, calibration and reliability assessments. Conclusion: This study design and method assessments provide solid documentation that public dental clinics are suitable as arenas for data collection in epidemiological oral health studies in the S ami population in this region.