The results suggest that immigrant groups in western societies require different information packages, modified strategies for forming oral hygiene habits and attitudes related to dental care of children, and encouragement to exercise discipline on factors known to be risks for oral health. These strategies must recognize that immigrants and western natives attach different levels of importance to oral health and dental parameters. It should be paid extra attention to some caries high-risk subgroups.

This study investigates the relationships among socio-demographic factors, dental status, and impaired oral health-related quality of life (OHRQoL) using a translation into Norwegian of the Oral Impacts on Daily Performance (OIDP) inventory. Data were collected as part of the Central Bureau of Statistics (CBS) OMNIBUS survey in Norway. The CBS drew a two-stage proportionate random sample, comprising 2,000 residents aged 16-79 yr, from the national population register. Information was available for 1,309 individuals (response rate 66.0%) who completed telephone interviews in November and December 2003. A total of 18.3% (95% confidence interval: 16.2-20.4) reported that an oral problem had affected at least one daily oral performance during the 6 months preceding the survey. The proportion of adults who confirmed impacts varied from 11.3% (eating) to 2.1% (social contact). Multiple logistic regression analysis revealed statistically significant disparities regarding respondents' age, residential area, dental attendance, and number of remaining teeth. The prevalence of OIDP in the Norwegian population was modest, but varied systematically with both socio-demographic and oral health-related factors. The consistently declining OIDP with increasing age after controlling for dental status suggests age-related changes of participants' values and expectations.

The Oral Impacts on Daily Performance (OIDP) instrument was translated into Norwegian and reviewed for cultural and conceptual equivalence by a group of bilingual academics. A sample of employees from the University of Bergen completed the Norwegian OIDP frequency questionnaire twice. A total of 173 and 108 subjects participated in the first and the second administration, respectively, of this questionnaire. A two-stage proportionate random sample, comprising 2,000 residents (age-range 16-79 yr), was drawn from the national population register by the Central Bureau of Statistics. Information became available for 1,309 persons who completed telephone interviews. The Norwegian OIDP preserved the overall concept of the English version. Test-retest reliability, in terms of Cohen's kappa, was 0.65, and Cronbach's alpha was high (> or = 0.80). In both samples, variations in the OIDP scores were apparent in relation to self-reported oral health and number of remaining teeth, supporting construct and criterion validity of the inventory. Only three of the OIDP interviews were discarded, which supports face validity. A total of 18.3% confirmed that they had at least one oral impact. Age-specific rates were 17.5%, 19.0%, 17.9% and 18.4% among 16-24, 24-44, 45-66 and 67-79-yr-old participants. The satisfactory psychometric properties provide evidence for the cross-cultural use of the OIDP. The presence of a distinct floor effect indicates poor sensitivity of the OIDP to detect improvements of oral health-related quality of life at a population level. Prevalence estimates were low, suggesting that the current oral health status has little impact on the daily performance of the Norwegian adult population.

The purpose of the present study was to investigate time trends in primary reasons for extraction of permanent teeth in Norway from 1968 to 1988. Johansen studied reasons for extraction of 8757 teeth in 4216 patients during a 3-week period in 1968. Twenty years later a random sample of 500 Norwegian dentists provided particulars about all extractions carried out during a 2-week period. 350 dentists (70%) replied in 1988 but 96 of them had not extracted any teeth during the observation period. Reasons for extraction of 985 teeth from 692 patients were available for analysis. Caries and its sequelae accounted for 35%, periodontitis for 19%, and orthodontic reasons for 20% of extractions in 1988. A comparison of the distribution of extraction according to reasons for patients over 20 yr of age revealed a highly significant difference between 1968 and 1988 (P less than 0.001) mainly due to a decrease in the role of caries and an increase in extractions for other reasons. Caries and its sequelae accounted for a higher proportion of extractions than periodontitis at all ages over 20 yr in 1968, only up to 45 yr of age in 1988. Thus it is concluded that the observed time trend in primary reasons for extraction corroborates expectations based on declining caries prevalence, increasing retention of teeth and a rise in dental attendance in Norway during the last 20 yr.

Socio-economic inequality in dental status persists among Norwegians aged 25-79 years but absolute differences have decreased during the last 30 years. The findings are encouraging but challenging as far as choice of strategy for further reduction of differences in tooth loss.