Efficacy of one-step and multi-step polishing systems in finishing direct composite restoration: a non-randomised controlled experimental trial

Background. The variety of polishing systems and tools available for finishing direct composite restorations may perplex the dentist.Objectives. An effect evaluation in one- and multi-step composite polishing tools using model specimens of GC Gradia Direct and 3M ESPE Filtek Ultimate restoratives.Methods. The prepared specimens of GC Gradia Direct and 3M ESPE Filtek Ultimate restorative composites were exposed in laboratory to the Kenda Maximus, Dentsply PoGo, Kagayaki RoundFlex, Shofu Super-Snap, Kagayaki Ensmart Pin, EVE Composoft polishing systems and Daiyamondo Kagayaki paste. The polishing systems distinguished by brand, technical and performance characters.Surface microgeometry in all 16 samples was estimated in the Laboratory of Optical Metrology, Institute of Design and Technology for Scientific Instrument Engineering, Novosibirsk, using a MNP-1 light interferometric nanoprofile microscope and at the shared core facilities of the Research and Education Centre “Nanomaterial Diagnostics and Properties” of Kuban State University, Krasnodar, using a JEOL JSM-7500F scanning electron microscope.Results. Optical profilometry and scanning electron microscopy were used to estimate surface roughness in 16 specimens exposed to polishing for one minute. The polishing tools Kenda Maximus, Dentsply PoGo, Kagayaki RoundFlex, Shofu Super-Snap, Kagayaki Ensmart Pin, EVE Composoft, as well as Daiyamondo Kagayaki paste used in instrumental polishing, revealed a varied performance. Optical profilometry exhibited the GC Gradia Direct and Filtek Ultimate specimens to possess the lowest average roughness in two cases: 1) after multi-step polishing with Kagayaki Ensmart Pin tools with Daiyamondo Kagayaki paste (average roughness corresponded to Sa — 0.214 pm in GC Gradia Direct and Sa — 0.248 pm — in Filtek Ultimate), 2) in application of the Kenda Maximus monopolishing tool (roughness values of Sa — 0.211 and Sa — 0.242 pm, respectively). Surface roughness after multi-step machining with EVE Composoft silicone polishers was average Sa — 0.579 and Sa — 0.549 pm in both samples and was reported the highest. Scanning electron microscopy confirmed the optical profilometry estimates.Conclusion. The assay showed that the specimen machining with a sole Kenda Maximus diamond abrasive tool and several Kagayaki Ensmart Pin silicone polishing heads followed by a Daiyamondo Kagayaki diamond abrasive paste application produced very similar surface roughness values, which were graded the lowest with GC Gradia Direct and 3M ESPE Filtek Ultimate composite samples using scanning electron microscopy and optical profilometry

Correction of Scanning Steps to Improve Accuracy in Interferometric Profilometer

In scanning interferometry of longitudinal shift, an uncertainty of required phase shift performance leads to a measurement error. Such uncertainty can be caused by external factors (vibrations, air turbulence in measuring area etc.) as well as inaccuracy of the scanning system. The method for calculating the phase shift between interferograms, which allows reducing the measurement error, is proposed. The results of numerical and full scale experiments are presented

Difficulties in the differential diagnosis of epileptic and hypocalcemic seizures in children and adolescents

Epileptic seizures require differential diagnosis with other paroxysmal conditions, including metabolic seizures. A variety of electrolyte changes can result in central nervous system dysfunction, including that as convulsive seizures. The paper describes electrolyte disorders leading to seizures, as well as their clinical features. It separately presents the  syndromes accompanied by hypocalcemia, in which there may be  convulsive paroxysms. The paper describes three clinical cases of  hypocalcemic seizures. It gives recommendations for the diagnosis and  management of patients with suspected metabolic seizures

Diatom succession trends in recent sediments from Lake Baikal and their relation to atmospheric pollution and to climate change

Recent environmental change in Lake Baikal has been attributed to anthropogenic influences on the ecosystem, especially through pollution and cultural eutrophication. These hypotheses are tested in this paper principally by diatom analyses in 20 short sediment cores. Most of the cores were collected with a new type of box corer specifically designed for use on Lake Baikal. Most cores contain a good sediment record but turbidites occur in some sediment profiles which may be best recognized using a combination of techniques, such as radiometric dating and percentage dry weight analyses. The most recent sediments, especially those in the southern basin and in the very north of Baikal, contain a record of anthropogenic contamination in the form of lead and spheroidal carbonaceous particles, which confirms that the southern basin of Baikal is most affected by atmospheric sources of pollution. However, there is no sedimentary diatom evidence indicating offshore water quality deterioration in Baikal owing to air pollution or eutrophication. Small increases in diatoms which indicate nutrient enrichment (e.g. Stephanodiscus minutulus, Synedra acus v. radians and Synedra acus v. acus) may reflect local eutrophication of the shallow waters close to the Selenga Delta and certain coastal sites in the southern basin near to the Baikalsk paper and pulp mill. By using numerical techniques, Lake Baikal can be split into at least four regions on the basis of its surface sediment flora: the south, middle and north basins, and the shallow waters surrounding the Selenga Delta region. Diatom analyses reveal that the endemic flora of Lake Baikal has been constantly changing over at least the last 2000 years and that these fluctuations are probably responses to natural climatic variability. Recent sediments of Baikal may be affected by taphanomic processes (e.g. dissolution) and turbidite deposition, and these must be taken into account when interpreting the sedimentary diatom record. The diatom flora of the lake is currently dominated by several species, such as Aulacoseira baicalensis, A. islandica, Cyclotella minuta and Stephanodiscus binderanus v. baicalensis. All these species, except for C. minuta, have become more common in the lake in approximately the last 130 years, and we hypothesize that these changes may be attributed to a number of different processes linked to an ameliorating climate after the end of the Little Ice Age. The results presented here have important implications for this recently designated World Heritage Site, with regard to future pollution controls and catchment management policies