| 1. |
- Al-Taai, Nameer, et al.
(författare)
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A Superimposition-Based Cephalometric Method to Quantitate Craniofacial Changes
- 2021
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Ingår i: International Journal of Environmental Research and Public Health. - : MDPI AG. - 1660-4601 .- 1661-7827. ; 18
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Tidskriftsartikel (refereegranskat)abstract
- To assess the craniofacial changes related to growth and/or to orthodontic and orthognathic treatments, it is necessary to superimpose serial radiographs on stable structures. However, conventional superimposition provides only a graphical illustration of these changes. To increase the precision of growth and treatment evaluations, it is desirable to quantitate these craniofacial changes. The aims of this study were to (1) evaluate a superimposition-based cephalometric method to process numerical data for craniofacial growth changes and (2) identify a valid, reliable, and feasible method for superimposition. Forty pairs of cephalograms were analyzed at T1 and T2 (mean age 9.9 and 15.0 years, respectively). The superimposition-based cephalometric method involved relating the sagittal and vertical measurements on the T2 radiographs to the nasion and sella landmarks on the T1 radiographs. Validity and reliability were evaluated for three superimposition methods: the sella-nasion (SN); the tuberculum sella-wing (TW); and Bjork's structural. Superimposition-based cephalometrics can be used to quantify craniofacial changes digitally. The numerical data from the superimposition-based cephalometrics reflected a graphical illustration of superimposition and differed significantly from the data acquired through conventional cephalometrics. Superimposition using the TW method is recommended as it is valid, reliable, and feasible.
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| 2. |
- Al-Taai, Nameer, et al.
(författare)
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Craniofacial changes from 13 to 62 years of age
- 2022
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Ingår i: European Journal of Orthodontics. - : Oxford University Press (OUP). - 0141-5387 .- 1460-2210. ; 44:5, s. 556-565
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Tidskriftsartikel (refereegranskat)abstract
- 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 between 13 and 62 years of age. Materials/Methods Thirty subjects with a Class I normal occlusion and harmonious facial profile 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 significant anterior growth from T1 to T2, and significant retrognathism from T3 to T4. The anterior face height and jaw dimensions increased significantly until T3. Significant posterior rotation of the mandible and opening of the vertical jaw relation, in addition to significant retroclination of the incisors and straightening of the facial profile, 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, vertical jaw relation and inclination, and posterior face height.
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| 3. |
- Al-Taai, Nameer, et al.
(författare)
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Dentoskeletal and soft tissue changes after treatment of crowding with premolar extractions: a 50-year follow-up
- 2023
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Ingår i: European Journal of Orthodontics. - : Oxford University Press (OUP). - 0141-5387 .- 1460-2210. ; 45:1, s. 79-87
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Tidskriftsartikel (refereegranskat)abstract
- Background The long-term effects on dentofacial morphology of interceptive treatment with premolar extractions, in the absence of subsequent orthodontic treatment, have not been fully explored. Objective The aim was to investigate the effects of premolar extractions (without subsequent orthodontic treatment) on the dentoskeletal and soft tissue profile of patients aged between 12 and 62 years with Class I malocclusion with severe crowding, as compared to untreated controls. Materials and methods The Extraction group (N = 30 with Class I crowding malocclusion) had their first premolars removed in early adolescence without subsequent orthodontic treatment. The Control group included 30 untreated subjects with Class I normal occlusion. Cephalograms were taken at 12 (T1), 15 (T2), 30 (T3), and 62 (T4) years of age. A superimposition-based cephalometric method was used to assess the dentoskeletal and soft tissue changes. Results There were no significant differences between the Extraction and Control groups in terms of skeletal sagittal relation, incisor inclination, and protrusion, or most of the soft tissue parameters throughout the observation period. However, significant differences were observed between the groups with respect to the vertical relations in T2-T3, such that the Extraction group showed more-pronounced decreases in the ML/NSL, ML/NL, and Gonial angles and more-pronounced increases in facial heights. Conclusions and implications Treatment for subjects with Class I malocclusion with severe crowding by the extraction of four premolars, without subsequent orthodontic treatment, does not affect the long-term dentoskeletal and soft tissue profile, as compared to an untreated Control group. The degree of crowding, rather than changes in dentofacial morphology, is crucial in deciding on extraction therapy.
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| 4. |
- Berg, Veronica, et al.
(författare)
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Swallowing and inhaling foreign objects during treatment
- 2004
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Ingår i: Tandläkartidningen. ; 96:7, s. 58-64
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Tidskriftsartikel (refereegranskat)abstract
- Three hundred dentists in private and 300 dentists in public dentistry were asked to fill in a questionnaire on the incidents of patients swallowing and inhaling objects during treatment. The response rate was 81%. The incident information provided in the questionnaire was compared to reports sent to the Socialstyrelsen (National Board of Health and Welfare), according to lex Maria for the period 1992-2002.Approximately one quarter of the dentists questioned reported an experience of a patient swallowing or inhaling a foreign object during the last 10 years, with a similar incidence seen between private and public dentistry. About two thirds of the situations reported occurred in treatments related to prosthetic dentistry. However, a marked difference between dentists in private and public service was found in the number of reported incidents to the Socialstyrelsen. The questionnaire showed that dentists lacked information and training in the handling of situations of swallowing and aspiration. The study concluded that official reports on swallowing and aspiration of foreign objects during dental treatment do not reflect the true incidence of occasions and highlighted the need for education and training of dentists in how to handle such situations.
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| 5. |
- Fijneman, Andreas J., et al.
(författare)
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Local quantification of mesoporous silica microspheres using multiscale electron tomography and lattice Boltzmann simulations
- 2020
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Ingår i: Microporous and Mesoporous Materials. - : Elsevier BV. - 1387-1811. ; 302
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Tidskriftsartikel (refereegranskat)abstract
- The multiscale pore structure of mesoporous silica microspheres plays an important role for tuning mass transfer kinetics in technological applications such as liquid chromatography. While local analysis of a pore network in such materials has been previously achieved, multiscale quantification of microspheres down to the nanometer scale pore level is still lacking. Here we demonstrate for the first time, by combining low convergence angle scanning transmission electron microscopy tomography (LC-STEM tomography) with image analysis and lattice Boltzmann simulations, that the multiscale pore network of commercial mesoporous silica microspheres can be quantified. This includes comparing the local tortuosity and intraparticle diffusion coefficients between different regions within the same microsphere. The results, spanning more than two orders of magnitude between nanostructures and entire object, are in good agreement with bulk characterization techniques such as nitrogen gas physisorption and add valuable local information for tuning mass transfer behavior (in liquid chromatography or catalysis) on the single microsphere level.
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| 6. |
- Fors, Ronny, et al.
(författare)
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Lifestyle and nickel allergy in a Swedish adolescent population : effects of piercing, tattooing and orthodontic appliances
- 2012
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Ingår i: Acta Dermato-Venereologica. - : Society for the Publication of Acta Dermato - Venereologica. - 0001-5555 .- 1651-2057. ; 92:6, s. 664-668
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 7. |
- Fors, Ronny, et al.
(författare)
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Nickel allergy : prevalence in a population of Swedish youths from patch test and questionnaire data
- 2008
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Ingår i: Contact Dermatitis. - Copenhagen : Munksgaard. - 0105-1873 .- 1600-0536. ; 58:2, s. 80-87
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 8. |
- Fors, Ronny, 1969-
(författare)
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Nickel allergy in a Swedish adolescent population and its relation to orthodontic treatment and lifestyle factors
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Nickel stands out as the main cause of contact allergy in both children and adults, which has given rise to concern and the introduction of regulations by official bodies. Today´s youths are frequently exposed to body piercing and orthodontic treatment. Changes in youth lifestyle practices are also likely to influence nickel exposure and thus, the occurrence of nickel allergy. However, against patient and parental concern regarding nickel exposure to orthodontic appliances, often evoked by allergies following piercing, stand results from studies indicating that early orthodontic appliance treatment may reduce, rather than increase, prevalence of nickel allergy; a finding that has been suggested to result from tolerance induction by early exposure to nickel via the oral route. The objective of the present thesis was to investigate the association between nickel allergy and exposure to different orthodontic appliances and lifestyle, in particular piercing, as well as to study nickel release from orthodontic appliances into the oral cavity. Furthermore, one objective was to establish baseline prevalence data of nickel allergy in a Swedish adolescent population. Data was generated from a cross-sectional survey, in which about 6000 youths completed a questionnaire and almost 4500 of these were patch-tested for contact allergy. Information on exposure to orthodontic appliances was verified by dental records, whilst nickel content in saliva and dental biofilm was measured in a clinical study. Questionnaire data demonstrated a reduced risk of nickel allergy when orthodontic treatment preceded piercing (OR 0.5; 95 % CI 0.3-0.8) and similar results were found for data verified from dental records, however statistical significance was lost when adjusting for background factors (OR 0.6, 95 % CI 0.4-1.0). Exposure to full fixed appliances with NiTi-containing alloys, as well as a pooled ‘high nickel-releasing’ appliance group prior to piercing correlated with a significantly reduced risk of nickel allergy and a trend towards a reduced risk with exposure duration. Nickel could also be found in significantly higher concentrations from dental plaque samples, but not saliva samples, in orthodontic patients who were well into treatment compared to patients who had not been exposed to orthodontic appliances. The effect was not found to be due to differences in estimated dietary nickel intake between the two groups. Significantly more girls than boys (13.3 % versus 2.5 %) were found to be patch-test positive to nickel. Positive nickel tests were also most prevalent in occupational programmes and least prevalent in natural science programmes, indicating differences in lifestyle and exposure to nickel. Dropout from testing was handled using a missing-value analysis. This internal validation showed that our results overestimated the occurrence of nickel allergy to a minor degree. More girls than boys reported piercing, vegetarian/vegan diet, and smoking practices, whereas an interesting shift in tattooing prevalence was observed with a larger proportion of girls reporting this practice compared to boys. Sex, number of piercings, smoking and orthodontic appliance treatment prior to piercing were found to influence weighted risk estimates of nickel allergy. To conclude, although orthodontic patients are exposed to nickel intraorally, we found no increased risk of sensitising adolescents to nickel by the use of oral orthodontic appliances. On the contrary, early orthodontic treatment preceding piercing reduced the risk of nickel allergy by a factor of 1.5-2.0. This reduced risk appears to be associated with estimated nickel release of the appliance and duration of treatment, in all supporting a hypothesised induction of immunological tolerance via oral administration of nickel. Our study also showed a strong association between lifestyle and nickel allergy. Although there have been changes in lifestyle over time, as indicated by the strong shift in tattooing practices, no large change in nickel allergy prevalence was found compared with previous Swedish data. Our data will serve as a baseline for future studies of the effect of nickel exposure regulations, such as the Nickel Directive, and for studies of lifestyle changes and their effects on nickel allergy.
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| 9. |
- Fors, Ronny, et al.
(författare)
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Nickel allergy in relation to piercing and orthodontic appliances : a population study
- 2012
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Ingår i: Contact Dermatitis. - : John Wiley & Sons. - 0105-1873 .- 1600-0536. ; 67:6, s. 342-350
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 10. |
- Fors, Ronny, et al.
(författare)
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Nickel in dental plaque and saliva in patients with and without orthodontic appliances.
- 2006
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Ingår i: European Journal of Orthodontics. - : Oxford University Press (OUP). - 0141-5387 .- 1460-2210. ; 28:3, s. 292-297
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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