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Reports of implant fixtures dislocating into the maxillary sinus during sinus graft procedures are well-documented. However, cases of fixtures migrating into the sinus long after placement have yet to be reported. This case report details the surgical extraction of a displaced screw and cement-retained prosthesis, including a fixture and its abutment, from the maxillary sinus after a minimum of 5 years under functional load. The extracted implant was subsequently examined using scanning electron microscopy and energy-dispersive x-ray spectroscopy. We found that the migration commenced with peri-implantitis surrounding the implant, replacing the second molar. This was accompanied by a loss of cement from the crown on this implant and concurrent loosening of the abutment screw on the implant, replacing the first molar. We hypothesize that the inability of the bony tissue surrounding the second molar implant to withstand occlusal forces resulted in forming a bony sequestrum. This process ultimately precipitated the migration of the fixture, along with its abutment and adjacent necrotic bone, into the sinus cavity. [ABSTRACT FROM AUTHOR]

The continuous scaling down of dynamic random access memory devices has necessitated a comprehensive understanding of the initial growth mechanism in atomic layer deposition. In this study, HfO2 was deposited using tetrakis(ethylmethylamido)hafnium (TEMAHf)-H2O on H-/OH-terminated Si (100) surfaces. By analyzing the Hf-O peak in the FTIR spectra and medium-energy ion scattering measurements, it was determined that a monolayer was formed on the H-Si surface at a rate (10 cycles) lower than that for the OH-Si surface (4 cycles). The ligand variations during each cycle, as determined by FTIR measurements, enabled the suggestion of the initial precursor adsorption mechanism. An analysis of the infrared spectra and secondary ion mass spectrometry depth profiles revealed surface-dependent differences in interfacial bonding. This explained the variation in the rate of formation of 1 Ml. Additionally, theoretical investigations using density functional theory calculations identified the reaction pathway with the lowest energy barrier, thereby validating the experimentally proposed mechanism. This study to elucidate the Si surface and the TEMAHf-H2O reaction mechanism provided insights into the analysis of the initial precursor adsorption mechanism for other types of precursors. [ABSTRACT FROM AUTHOR]

Electronic properties of 6 nm (HfO2)x(SiO2)1-x dielectric thin films, deposited on Si(100) by atomic layer deposition with x equal to 0.75 and 0.25, were studied by means of x-ray photoelectron spectroscopy (XPS) and reflection electron energy loss spectroscopy (REELS). XPS measurements confirmed the formation of a silicate structure, and showed shifts of the Hf 4f and Si 2p peaks with varying Hf concentrations; these shifts are believed to be caused by changes in the amount of charge transfer and by the substitution of Si by Hf as second-nearest-neighbors. The band gap, Eg, was estimated from REELS. It increased from 5.52 eV for Hf silicate with a Hf/Si ratio of 3:1 to 6.61 eV for Hf silicate with a Hf/Si ratio of 1:3. For Hf silicate dielectrics, the band gap is mainly determined by Hf 5d conduction-band and O 2p valence-band states, and the increase with increasing Si concentration is due to mixing with the Si 3s electrons. By quantitative analysis of REELS spectra, the dielectric functions of the thin films were also determined and expressed as a sum of oscillators. The position, strength, and width of the oscillators were determined quantitatively for the different dielectric films. [ABSTRACT FROM AUTHOR]