| 11. |
- Bakitian, Fahad, et al.
(författare)
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Effect of different semimonolithic designs on fracture resistance and fracture mode of translucent and high-translucent zirconia crowns
- 2018
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Ingår i: Clinical, Cosmetic and Investigational Dentistry. - : Nakladatelstvi Lidove noviny. - 1179-1357. ; 10, s. 51-60
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The aim of this study was to describe different designs of semimonolithic crowns made of translucent and high-translucent zirconia materials and to evaluate the effect on fracture resistance and fracture mode. Methods: One hundred crowns with different designs were produced and divided into five groups (n=20): monolithic (M), partially veneered monolithic (semimonolithic) with 0.3 mm buccal veneer (SM0.3), semimonolithic with 0.5 mm buccal veneer (SM0.5), semimonolithic with 0.5 mm buccal veneer supported by wave design (SMW), and semimonolithic with 0.5 mm buccal veneer supported by occlusal cap design (SMC). Each group was divided into two subgroups (n=10) according to the materials used, translucent and high-translucent zirconia. All crowns underwent artificial aging before loading until fracture. Fracture mode analysis was performed. Fracture loads and fracture modes were analyzed using two-way ANOVA and Fisher’s exact probability tests (P≤0.05). Results: SM0.3 design showed highest fracture loads with no significant difference compared to M and SMW designs (P>0.05). SM0.5 design showed lower fracture loads compared to SMW and SWC designs. Crowns made of translucent zirconia showed higher fracture loads compared to those made of high-translucent zirconia. M, SM0.3, and all but one of the SMC crowns showed complete fractures with significant differences in fracture mode compared to SMW and SM0.5 crowns with cohesive veneer fractures (P≤0.05). Conclusion: Translucent and high-translucent zirconia crowns might be used in combination with 0.3 mm microcoating porcelain layer with semimonolithic design to enhance the esthetic properties of restorations without significantly decreasing fracture resistance of the crowns. If 0.5 mm porcelain layer is needed for a semimonolithic crown, wave design or cap design might be used to increase fracture resistance. In both cases, fracture resistance gained is likely to be clinically sufficient as the registered fracture loads were high in relation to expected loads under clinical use.
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| 12. |
- Bakitian, Fahad, et al.
(författare)
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Evaluation of Stress Distribution in Tooth-Supported Fixed Dental Prostheses Made of Translucent Zirconia with Variations in Framework Designs : A Three-Dimensional Finite Element Analysis
- 2020
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Ingår i: Journal of Prosthodontics. - : John Wiley & Sons. - 1059-941X .- 1532-849X. ; 29:4, s. 315-322
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Tidskriftsartikel (refereegranskat)abstract
- Purpose To evaluate the influence of the framework designs on the stress distribution within tooth-supported partially veneered fixed dental prostheses (FDPs) made of translucent zirconia under simulated loads using a three-dimensional finite element analysis (3D-FEA). Material and Methods For a linear 3D-FEA, simplified 3D solid models of prepared abutment teeth (first premolar and first molar) with different 3-unit FDPs were created. The models with different FDP designs-monolithic zirconia (control); semi-monolithic zirconia with 0.3 mm veneer thickness (SM0.3); semi-monolithic zirconia with 0.5 mm veneer thickness (SM0.5); semi-monolithic zirconia with 0.5 mm veneer thickness supported with cap design (SMC), and semi-monolithic zirconia with 0.5 mm veneer thickness supported with wave design (SMW)-were analyzed using 3D-FEA. The elastic properties of the components (bone, dentine, cement, translucent zirconia, and veneering porcelain) were obtained from the published data for FEA. Simulated static loading forces (300 N) were applied at 10 degrees oblique direction over six points in the occlusal surfaces of the FDPs. Maximum principal stress, shear stress, and safety factor were calculated and analyzed among the different models. Results Semi-monolithic with cap design showed the smallest maximum principal stress levels in the veneering porcelain compared to all other models (SM0.3, SM0.5, SMW). The SM0.3 had lower maximum principal stress levels in the veneering porcelain compared to SM0.5. Regarding stresses in the zirconia framework, all models had comparable results in maximum principal tensile stresses, except SMW had a lower value. Maximum principal stress levels were located in the veneer component of SM0.3, SM0.5, and SMW, whereas, such levels were observed in the cervical areas of the zirconia frameworks of SMC and control. The SM0.3 had the highest maximum shear stress levels at the zirconia-veneer interface, while SMW had the lowest shear values. The 3D-FEA models with different FDP designs showed different minimum safety factor levels. Conclusions Framework and veneer designs play a significant role in the stress distribution of the partially veneered zirconia FDPs under loading. The FDPs with zirconia frameworks with cap design minimize the maximum principal tensile stress in the veneering porcelain. The FDPs with 0.3-mm-veneering porcelain show low maximum principal tensile stress in the veneering porcelain, but highest maximum shear stress at the zirconia-veneer interface. The FDPs with wave design of zirconia frameworks minimize the maximum shear stress considerably.
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| 13. |
- Bakitian, Fahad, et al.
(författare)
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Fracture strength of veneered translucent zirconium dioxide crowns with different porcelain thicknesses.
- 2017
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Ingår i: Acta Biomaterialia Odontologica Scandinavica. - : Taylor & Francis. - 2333-7931. ; 3:1, s. 74-83
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Objective: To evaluate fracture strength of veneered translucent zirconium dioxide crowns designed with different porcelain layer thicknesses. Materials and Methods: Sixty crowns, divided into six groups of 10, were used in this study. Groups were divided according to different thicknesses of porcelain veneer on translucent zirconium dioxide cores of equal thickness (0.5 mm). Porcelain thicknesses were 2.5, 2.0, 1.0, 0.8, 0.5 and 0.3 mm. Crowns were artificially aged before loaded to fracture. Determination of fracture mode was performed using light microscope. Results: Group 1.0 mm showed significantly (p ≤ .05) highest fracture loads (mean 1540 N) in comparison with groups 2.5, 2.0 and 0.3 mm (mean 851, 910 and 1202 N). There was no significant difference (p>.05) in fracture loads among groups 1.0, 0.8 and 0.5 mm (mean 1540, 1313 and 1286 N). There were significantly (p ≤ .05) more complete fractures in group 0.3 mm compared to all other groups which presented mainly cohesive fractures. Conclusions: Translucent zirconium dioxide crowns can be veneered with minimal thickness layer of 0.5 mm porcelain without showing significantly reduced fracture strength compared to traditionally veneered (1.0–2.0 mm) crowns. Fracture strength of micro-veneered crowns with a layer of porcelain (0.3 mm) is lower than that of traditionally veneered crowns but still within range of what may be considered clinically sufficient. Porcelain layers of 2.0 mm or thicker should be used where expected loads are low only.
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| 14. |
- Bakitian, Fahad, et al.
(författare)
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Load-Bearing Capacity of Monolithic Zirconia Fixed Dental Prostheses Fabricated with Different Connector Designs and Embrasure Shaping Methods
- 2019
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Ingår i: Journal of Prosthodontics. - : John Wiley & Sons. - 1059-941X .- 1532-849X. ; 28:1, s. 64-70
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Tidskriftsartikel (refereegranskat)abstract
- Aim> To investigate the load-bearing capacity and failure mode of monolithic zirconia fixed dental prostheses (FDPs) fabricated with different connector designs and embrasure shaping methods. Materials and methods> Seventy 4-unit zirconia FDPs (with 2 premolar pontics) were fabricated and divided into 7 groups (n = 10) according to the different connector designs gained by using different embrasure shaping methods. The groups were as follows: monolithic FDPs fabricated with sharp embrasures, monolithic FDPs fabricated with blunt embrasures, monolithic FDPs fabricated with blunt embrasures and no occlusal embrasures, 2 groups of monolithic FDPs fabricated with blunt embrasures and interproximal separations made with diamond discs at the soft stage and at the fully sintered stage, and monolithic FDPs fabricated with blunt embrasures and interproximal separation accentuated by localized porcelain build-up. A final group of fully veneered traditional zirconia FDPs to be used as a control group were fabricated with default milling settings. The FDPs were artificially aged and loaded to fracture. Load to fracture and failure modes were analyzed by 1-way ANOVA, Tukey post-hoc test, and Fisher exact test (α = 0.05). Results> The FDPs fabricated with interproximal porcelain separation showed significantly the highest load to fracture (1038 N ± 82) of all groups (p < 0.001), with no significant difference compared to the FDPs with no occlusal embrasures (934 N ± 175) (p ˃ 0.29). The FDPs fabricated with blunt embrasures showed significantly higher load to fracture (873 N ± 115) compared to the FDPs in control group (689 N ± 75) and the FDPs with sharp embrasures (417 N ± 87) (p < 0.001). There were no significant differences between the FDPs with sharp embrasures (417 N ± 87) and the FDPs with interproximal discs separations (467 N ± 94; p ˃ 0.23). Failure mode of the FDPs fabricated with sharp embrasures and interproximal discs separations differed significantly compared to the FDPs in the other groups (p < 0.001). Conclusions> Sharp embrasures and interproximal separations made with diamond discs significantly decrease the load-bearing capacity of monolithic zirconia FDPs compared to FDPs made with blunt embrasures. Blunt embrasures in combination with localized porcelain build-up produce FDPs with high load-bearing capacity in relation to loads that might be expected under clinical use. This article is protected by copyright. All rights reserved.
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| 15. |
- Berg, Christina, 1963, et al.
(författare)
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Dieting, body weight concerns and health: trends and associations in Swedish schoolchildren.
- 2020
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Ingår i: BMC public health. - : Springer Science and Business Media LLC. - 1471-2458. ; 20:1
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Tidskriftsartikel (refereegranskat)abstract
- Dieting is a risk factor of both eating disorders and obesity. The aim was to examine time trends of dieting in Swedish adolescents, and explore how dieting and body weight dissatisfaction are related to self-reported health, wellbeing and health behaviours.Analyses of cross-sectional Swedish data from HBSC (Health Behaviour in School-aged Children) surveys 1994-2014. In total, about 30,000 girls and boys in the age of 11, 13 and 15years participated. Data was collected by using classroom administered questionnaires in 5th, 7th and 9th grade. Logistic regressions was used to analyse secular trends of dieting, and how dieting and body dissatisfaction were associated with self-reported overall health, health behaviours, BMI and various physical, psychological and social aspects of health in 2014.Dieting increased from 1994 to 2014 in both girls and boys in all age groups, and in 2014, the prevalence was 14% in girls and 8% in boys. The prevalence of body satisfaction was 65% respectively 69%. Body weight dissatisfaction and dieting were present in all body weight classes and were associated with self-reported poor health and many other negative health aspects. In comparison with the participants that were satisfied with their body weight the odds ratio (95% CI) for self-reported poor health was 3.4 (2.6-4.4) in dieters, 4.9 (3.8-6.4) in participants who perceived a need to lose weight and 2.1 (1.5-2.8) in those who perceived a need to gain weight, when adjusting for age, sex and body weight class.When promoting health among school age children body weight dissatisfaction and dieting ought to be considered. Furthermore, it is important to support girls and boys in all weight classes to reach and maintain a healthy body image and weight.
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| 16. |
- Berg, Christina, 1963, et al.
(författare)
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Livsmedel och kostmönster
- 2021
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Ingår i: Näringslära för högskolan. - : Liber. - 9789147131075
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 17. |
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| 18. |
- Berg, Staffan, et al.
(författare)
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Evaluation in pig of an intestinal administration device for oral peptide delivery
- 2023
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Ingår i: Journal of Controlled Release. - : Elsevier. - 0168-3659 .- 1873-4995. ; 353, s. 792-801
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Tidskriftsartikel (refereegranskat)abstract
- The bioavailability of peptides co-delivered with permeation enhancers following oral administration remains low and highly variable. Two factors that may contribute to this are the dilution of the permeation enhancer in the intestinal fluid, as well as spreading of the released permeation enhancer and peptide in the lumen by intestinal motility. In this work we evaluated an Intestinal Administration Device (IAD) designed to reduce the luminal dilution of drug and permeation enhancer, and to minimize movement of the dosage form in the intestinal lumen. To achieve this, the IAD utilizes an expanding design that holds immediate release mini tablets and places these in contact with the intestinal epithelium, where unidirectional drug release can occur. The expanding conformation limits movement of the IAD in the intestinal tract, thereby enabling drug release at a single focal point in the intestine. A pig model was selected to study the ability of the IAD to promote intestinal absorption of the peptide MEDI7219 formulated together with the permeation enhancer sodium caprate. We compared the IAD to intestinally administered enteric coated capsules and an intestinally administered solution. The IAD restricted movement of the immediate release tablets in the small intestine and histological evaluation of the mucosa indicated that high concentrations of sodium caprate were achieved. Despite significant effect of the permeation enhancer on the integrity of the intestinal epithelium, the bioavailability of MEDI7219 was of the same order of magnitude as that achieved with the solution and enteric coated capsule formulations (2.5–3.8%). The variability in plasma concentrations of MEDI7219 were however lower when delivered using the IAD as compared to the solution and enteric coated capsule formulations. This suggests that dosage forms that can limit intestinal dilution and control the position of drug release can be a way to reduce the absorptive variability of peptides delivered with permeation enhancers but do not offer significant benefits in terms of increasing bioavailability.
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| 19. |
- Bergström, Christel A S, 1973-, et al.
(författare)
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Computational prediction of drug solubility in water-based systems : qualitative and quantitative approaches used in the current drug discovery and development setting
- 2018
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Ingår i: International Journal of Pharmaceutics. - : Elsevier BV. - 0378-5173 .- 1873-3476. ; 540:1-2, s. 185-193
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Forskningsöversikt (refereegranskat)abstract
- In this review we will discuss recent advances in computational prediction of solubility in water-based solvents. Our focus is set on recent advances in predictions of biorelevant solubility in media mimicking the human intestinal fluids and on new methods to predict the thermodynamic cycle rather than prediction of solubility in pure water through quantitative structure property relationships (QSPR). While the literature is rich in QSPR models for both solubility and melting point, a physicochemical property strongly linked to the solubility, recent advances in the modelling of these properties make use of theory and computational simulations to better predict these properties or processes involved therein (e.g. solid state crystal lattice packing, dissociation of molecules from the lattice and solvation). This review serves to provide an update on these new approaches and how they can be used to more accurately predict solubility, and also importantly, inform us on molecular interactions and processes occurring during drug dissolution and solubilisation.
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| 20. |
- Bergvall, Hanna, et al.
(författare)
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Gender differences in self-assessment among dental students at an ”Objective Structured Clinical Examination (OSCE).
- 2014
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Objective: The objective of this study was to compare dental student’s real/practical results at an Objective Structured Clinical Examination (OSCE) with their self-assessed results. These results were compared depending on gender. Introduction: There are several studies published comparing differences in self-assessment between women and men in theoretical exams. However, knowledge is lacking in regards to clinical examinations. At theoretical examinations, it has been found that men tend to over-estimate their performance more frequently than women do. Whether these differences in self-assessment exist because men tend to over-estimate themselves, women tend to under-estimate themselves, a combination of both or that self-assessments actually are consistent with the results at the examination, vary between different studies. Materials and methods: All students (35 women and 16 men) at the sixth semester at Malmö Dental School were examined with an OSCE with 13 stations. The student’s real results at OSCE were compared with their self-assessment at each station. The assessments were compared regarding gender. Results: At most of the 13 stations there were no significant differences in over- and under-estimation regarding women and men. It was more difficult for men to assess their performance regarding impression with alginate. These misjudgments were mainly caused by over-estimation. There were no results indicating that women under-estimate their performance at greater extent than men. Conclusion: Contrary to studies where gender differences concerning self-assessment in theoretical examinations are observed, the present study found no significant differences in over- and under-estimation between women and men.
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