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Background: In long-term studies of orthodontic, orthognathic, and prosthodontic treatments, control subjects are needed for comparison.

Objectives: To study the craniofacial (skeletal, soft tissue, and dental) changes that occur in untreated subjects with normal occlusion between13 and 62 years of age.

Materials/Methods: Thirty subjects with a Class I normal occlusion and harmonious facial profle were studied. X-ray examinations were performed at 13 (T1), 16 (T2), 31 (T3), and 62 (T4) years of age, and data were obtained from cephalograms. In total, 53 angular and linear parameters were measured using superimposition-based and conventional cephalometric methods to describe the craniofacial changes.

Results: The jaws showed signifcant anterior growth from T1 to T2, and signifcant retrognathism from T3 to T4. The anterior face height andjaw dimensions increased signifcantly until T3. Signifcant posterior rotation of the mandible and opening of the vertical jaw relation, in additionto signifcant retroclination of the incisors and straightening of the facial profle, were found from T3 to T4.Limitations: Given the small sample size at T4, it was not possible to analyse the gender dimension.

Conclusions/Implications: Craniofacial changes continue up to the sixth decade of life. These changes are consistent, albeit to a lesser extent,with the adolescent growth patterns for most of the studied parameters, with the exceptions of incisor inclination, sagittal jaw position, verticaljaw relation and inclination, and posterior face height.

The aim of this study was to estimate the prevalence of life-style practices in adolescents and their association with nickel allergy. Upper secondary school pupils (n = 4,376; 15-23 years) were patch-tested for nickel aller-gy, follow-ing completion of a questionnaire (answered by 6,095). Almost 86% girls and 21% of boys reported piercing. More girls (6%) than boys (3%) had a tattoo. Twenty-six percent of the girls and 18% of the boys were regular smokers. Vegetarian/vegan diets were reported by 20% of girls and by 6% of boys. Piercing, female gender, and vocational programme increased the risk of nickel allergy, whereas orthodontic appliance treat-ment prior to piercing reduced the risk of nickel allergy. Pupils in vocational programmes had the highest prevalence of nickel allergy. Lifestyle behaviours are interconnected and cluster in subgroups of adolescents. Female sex, piercing and choice of educational programme are prominent lifestyle markers. A trend shift is observed, where more girls than boys report tattooing.

Background. Studies have shown conflicting results on the association between nickel exposure from orthodontic appliances and nickel sensitization.

Objectives & Method. In a cross-sectional study, we investigated the association between nickel sensitization and exposure to orthodontic appliances and piercings. 4376 adolescents were patch tested following a questionnaire asking for earlier piercing and orthodontic treatment. Exposure to orthodontic appliances was verified in dental records.

Results. Questionnaire data demonstrated a reduced risk of nickel sensitization when orthodontic treatment preceded piercing (OR 0.46; CI 0.27–0.78). Data from dental records demonstrated similar results (OR 0.61, CI 0.36–1.02), but statistical significance was lost when adjusting for background factors. Exposure to full, fixed appliances with NiTi-containing alloys (OR 0.31, CI 0.10–0.98) as well as a pooled ‘high nickel-releasing’ appliance group (OR 0.56, CI 0.32–0.97) prior to piercing was associated with a significantly reduced risk of nickel sensitization.

Conclusion. High nickel-containing orthodontic appliances preceding piercing reduces the risk of nickel sensitization by a factor 1.5–2. The risk reduction is associated with estimated nickel release of the appliance and length of treatment. Sex, age at piercing and number of piercings are also important risk indicators. Research on the role of dental materials in the development of immunological tolerance is needed.

Background: The prevalence of body piercing and orthodontic treatment has increased during recent decades. Such changes in lifestyle may influence the occurrence of nickel allergy.

Objectives: The aim of this study was to describe the prevalence of nickel allergy in a Swedish youth population.

Methods: In a cross-sectional survey, 6095 adolescents answered a questionnaire on their lifestyle and medical history, and 4439 consented to patch testing for contact allergy. Patch test results were adjusted for dropouts by a missing value analysis.

Results: The prevalence of self-reported dermatitis from contact with metal items was 14.8%. Patch testing showed nickel sensitization in 9.9% of the subjects, and in significantly more girls than boys, 13.3% versus 2.5%, respectively. Taking the dropout into account, the estimated true prevalence of nickel sensitivity evaluated by test reading at D4 is 11.8% in girls and 1.6% in boys.

Conclusions: The prevalence of nickel sensitization was higher for girls and slightly lower for boys compared with previous Swedish data. Self-reported information on metal dermatitis as an estimate of nickel allergy has low validity. When possible, missing value analysis should be performed to account for dropouts.

The aim of this study was to compare the content of nickel in the saliva and dental biofilm in young patients with and without orthodontic appliances. The possible influence of a dietary intake of nickel on recorded nickel levels was examined. Nickel content in unstimulated whole saliva and in dental plaque of 24 boys and girls (mean age 14.8 years) with intraoral fixed orthodontic appliances was compared with 24 adolescents without such an appliance. Sample collection was set up to exclude nickel contamination. Diet intake was recorded for the preceding 48 hours to account for the influence of recent nickel content in food. Saliva and plaque were analysed for nickel content using an electrothermal atomic absorption spectrometric (ETAAS) method. The acidified saliva samples were analysed as Millipore-filtered saliva with filter-retained fractions and plaque following dissolution in acids. No significant difference in nickel content of filtered saliva was found between the test and the control samples (P = 0.607); the median values of nickel content were 0.005 and 0.004 mug/g saliva, respectively. On the other hand, a significant difference was found for the filter-retained fraction (P = 0.008); median values for nickel were 25.3 and 14.9 mug/g, respectively. A significant difference in nickel content between test and control samples was also found in plaque collected at various tooth sites (P = 0.001; median values 1.03 and 0.45 mug/g, respectively). A stronger difference was found when comparing plaque collected from metal-covered tooth surfaces than from enamel surfaces of orthodontic patients. No association could be found between calculated dietary intake of nickel and recorded nickel in the test and control samples. It is concluded that nickel release occurs into the dental plaque and components of saliva of orthodontic patients, a situation that may reflect time dependence of its release from orthodontic appliances into the oral cavity and an aggregation of nickel at plaque sites.