TY  - JOUR
A1  - Hahn, Britta
A1  - Haubitz, Imme
A1  - Krug, Ralf
A1  - Krastl, Gabriel
A1  - Soliman, Sebastian
T1  - Influence of matrix type on marginal gap formation of deep class II bulk-fill composite restorations
JF  - International Journal of Environmental Research and Public Health
N2  - Background: To test the hypothesis that transparent matrices result in more continuous margins of bulk-fill composite (BFC) restorations than metal matrices. Methods: Forty standardized MOD cavities in human molars with cervical margins in enamel and dentin were created and randomly assigned to four restorative treatment protocols: conventional nanohybrid composite (NANO) restoration (Tetric EvoCeram, Ivoclar Vivadent, Schaan, Liechtenstein) with a metal matrix (NANO-METAL) versus transparent matrix (NANO-TRANS), and bulk-fill composite restoration (Tetric EvoCeram Bulk Fill, Ivoclar Vivadent, Schaan, Liechtenstein) with a metal matrix (BFC-METAL) versus transparent matrix (BFC-TRANS). After artificial aging (2500 thermal cycles), marginal quality was evaluated by scanning electron microscopy using the replica technique. Statistical analyses were performed using the Mann–Whitney U-test and Wilcoxon test. The level of significance was p < 0.05. Results: Metal matrices yielded significantly (p = 0.0011) more continuous margins (46.211%) than transparent matrices (27.073%). Differences in continuous margins between NANO (34.482%) and BFC (38.802%) were not significant (p = 0.56). Matrix type did not influence marginal gap formation in BFC (p = 0.27) but did in NANO restorations (p = 0.001). Conclusion: Metal matrices positively influence the marginal quality of class II composite restorations, especially in deep cavity areas. The bulk-fill composite seems to be less sensitive to the influence of factors such as light polymerization and matrix type.
KW  - transparent matrix
KW  - metal matrix
KW  - bulk-fill technique
KW  - centripetal technique
KW  - marginal gap formation
KW  - class II restoration
KW  - SEM
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-270712
SN  - 1660-4601
VL  - 19
IS  - 9
ER  - 
TY  - JOUR
A1  - Chenari, Hossein Mahmoudi
A1  - Seibel, Christoph
A1  - Hauschild, Dirk
A1  - Reinert, Friedrich
A1  - Abdollahian, Hossein
T1  - Titanium Dioxide Nanoparticles: Synthesis, X-Ray Line Analysis and Chemical Composition Study
JF  - Materials Research
N2  - TiO2 nanoparticleshave been synthesized by the sol-gel method using titanium alkoxide and isopropanolas a precursor. The structural properties and chemical composition of the TiO2 nanoparticles were studied usingX-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy.The X-ray powder diffraction pattern confirms that the particles are mainly composed of the anatase phase with the preferential orientation along [101] direction. The physical parameters such as strain, stress and energy density were investigated from the Williamson- Hall (W-H) plot assuming a uniform deformation model (UDM), and uniform deformation energy density model (UDEDM). The W-H analysis shows an anisotropic nature of the strain in nanopowders. The scanning electron microscopy image shows clear TiO2 nanoparticles with particle sizes varying from 60 to 80nm. The results of mean particle size of TiO2 nanoparticles show an inter correlation with the W-H analysis and SEM results. Our X-ray photoelectron spectroscopy spectra show that nearly a complete amount of titanium has reacted to TiO2
KW  - TiO\(_2\)
KW  - Nanoparticles
KW  - X-ray analysis
KW  - SEM
KW  - XPS
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-165807
VL  - 19
IS  - 6
ER  -