Conclusion. Three-dimensional quantification of condylar morphology revealed profound differences between OA and asymptomatic condyles, and the extent of the resorptive changes paralleled pain severity and duration. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;110:110-117)”
“Au-core-Co-shell nanoparticles were synthesized by a wet-chemical method, and their magnetic properties were characterized. By comparing
the blocking temperature of Au-core-Co-shell nanoparticles to pure cobalt nanoparticles of the same size, it is proposed that cobalt spins in the shell are all aligned by exchange interaction to form single selleck domain nano shells. At the same time, a demagnetizing field in the gold core develops and is aligned along the magnetization direction
of the cobalt shell. A greatly enhanced coercivity of Au-core-Co-shell nanoparticles at 10 K, compared to the pure cobalt sample, was observed. We propose that the enhanced coercivity of Au-core-Co-shell nanoparticles is due to the pinning effect of cobalt spins at the Au/Co interface. The pinning mechanisms include strain pinning and demagnetizing field pinning. (C) 2011 American Institute of Physics. [doi:10.1063/1.3544493]“
“Objective. The objective of this website this study was to investigate cross sections of the apical part of premolar root canals and determine recommendations for their optimal apical preparation size.
Methodology. A total of 140 root canals from extracted human premolars (86 maxillary, 54 mandibular) were selected. After preflaring, the electronic working length (WL) was measured to identify where the apical preparation size (APS) should be established. Subsequently, nontapered, noncutting special instruments learn more (SI) were used to reach the WL. The diameter of the largest SI width
that reached the WL was defined as d(SI). The roots were apically sectioned at 2 levels, and the diameter of a potential rotary instrument was determined, allowing complete circumferential cutting of the root canal wall for each section. The estimation of APS was then related to d(SI).
Results. Apically enlarging upper premolars with 2 canals and lower premolars to an individual APS of d(SI) + 0.3 mm (6 file sizes) resulted in a 71% to 75% complete preparation of the root canal walls, whereas an enlarged preparation of d(SI) + 0.4 mm (8 file sizes) reached 82% to 96%. In upper premolars with a single canal, an APS of d(SI) + 0.3 mm completely processed the root canal walls in only 37%, whereas an APS of d(SI) + 0.4 mm reached 63%.
Conclusions. The APS in 2-canal upper premolars and mandibular premolars should be at least 6 sizes larger than the first apically binding file, whereas in upper premolars with a central canal, the APS should be enlarged to 8 sizes larger. Normally, this implies shaping premolars with 1 canal to #60 to 70 and with 2 canals to #40 to 50.