| 1. |
- Emami, N., et al.
(författare)
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Effect of light power density variations on bulk curing properties of dental composites
- 2003
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Ingår i: Journal of Dentistry. - : Elsevier BV. - 0300-5712 .- 1879-176X. ; 31:3, s. 189-196
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Tidskriftsartikel (refereegranskat)abstract
- Objective. The hypothesis that low light intensity and long but sufficient curing time can produce composites with volumetric shrinkage, degree of conversion (DC%) and Young's modulus (E-modulus) comparable to those of high light intensity cured composite was tested, when the contraction strain and heat generation were lower with Low Light intensity curing. Methods. Dental composites (Z100 and Z250, 3M ESPE) were investigated. Specimens were cured with Light intensities of 200, 450 and 800 mW/cm(2) for 140, 60 and 35 s from a distance of 7 mm. Strain-gages were used for contraction strain measurements. DC% was measured at the top and the bottom of 4 mm thick samples using FT-Raman spectroscopy. Volumetric polymerization shrinkage was determined using a water displacement method. E-modulus was determined in tension on composite specimens. Results. The results were analyzed using ANOVA and Duncan's multiple range tests and regular t-test. Polymerization stress Level decreased significantly (p < 0.05) when cured with 200 mW/cm(2) rather than with 800 mW/cm(2). Temperature rises were significantly different (p < 0.05) for different composites and light intensity values. Reduction in light intensity did not decrease the DC% values significantly at the top surfaces. The most dramatic differences existed between top and bottom surfaces (p < 0.05) rather than among curing groups. Measured E-modulus and volumetric shrinkage values were not significantly different (p > 0.05) between different light intensity groups. Conclusion. DC%, E-modulus and the volumetric shrinkage values in cured composites were not affected by low Light intensity, however, the contraction strain and polymerization's exotherm were decreased. Thus our results support the proposed hypothesis. Published by Elsevier Science Ltd.
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| 2. |
- Emami, Nazanin, et al.
(författare)
-
Effect of light power density variations on bulk curing properties of dental composites
- 2003
-
Ingår i: Journal of Dentistry. - 0300-5712 .- 1879-176X. ; 31:3, s. 189-196
-
Tidskriftsartikel (refereegranskat)abstract
- Objective. The hypothesis that low light intensity and long but sufficient curing time can produce composites with volumetric shrinkage, degree of conversion (DC%) and Young's modulus (E-modulus) comparable to those of high light intensity cured composite was tested, when the contraction strain and heat generation were lower with low light intensity curing. Methods. Dental composites (Z100 and Z250, 3M ESPE) were investigated. Specimens were cured with light intensities of 200, 450 and 800 mW/cm2 for 140, 60 and 35 s from a distance of 7 mm. Strain-gages were used for contraction strain measurements. DC% was measured at the top and the bottom of 4 mm thick samples using FT-Raman spectroscopy. Volumetric polymerization shrinkage was determined using a water displacement method. E-modulus was determined in tension on composite specimens. Results. The results were analyzed using ANOVA and Duncan's multiple range tests and regular t-test. Polymerization stress level decreased significantly (p<0.05) when cured with 200 mW/cm2 rather than with 800 mW/cm2. Temperature rises were significantly different (p<0.05) for different composites and light intensity values. Reduction in light intensity did not decrease the DC% values significantly at the top surfaces. The most dramatic differences existed between top and bottom surfaces (p<0.05) rather than among curing groups. Measured E-modulus and volumetric shrinkage values were not significantly different (p>0.05) between different light intensity groups. Conclusion. DC%, E-modulus and the volumetric shrinkage values in cured composites were not affected by low light intensity, however, the contraction strain and polymerization's exotherm were decreased. Thus our results support the proposed hypothesis.
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| 3. |
- Richter, J, et al.
(författare)
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Temperament and character in cross-cultural comparisons between Swedish and Iranian people and Iranian refugees in Sweden - Personality in transition?
- 2004
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Ingår i: Collegium Antropologicum. - 0350-6134 .- 1848-9486. ; 28:2, s. 865-876
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the study was a cross-cultural comparison of personality traits between individuals from two very different cultures and refugees who resettled several years before from one to the other. Four hundred forty four Swedish individuals of the normal population, and 100 Iranian refugees in Sweden, and a group of 335 individuals from Tehran, capital of Iran, were investigated by means of the Temperament and Character Inventory, a questionnaire to assess temperament and character. Iranians are those that are most frequently correctly classified followed by the Swedish based on temperament scores by means of a Discriminance analyses. Iranian refugees in Sweden were classified to about 50 per cent as Swedish and to slightly more then one-third as Iranians. Especially concerning character, 4 per cent only could be correctly classified as refugees. The results give some perspective on the adaptation process and personality changes in refugees several years after resettlement in another country with a complete different culture.
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