Effects of a drill diameter on the temperature rise in a bone during implant site preparation under clinical conditions.

Heat, generated during the drilling of a dental implant site preparation, leads to a temperature rise and consequently to a thermal injury of the bone tissue surrounding the implant site, which can cause the subsequent implant failure. In this article, we present new findings related to the temperature rise during implant site drilling under real conditions on a bovine rib bone specimen. The experiments were designed with the help of a full-factorial design in randomized complete blocks, where the main effects of the drill diameter in combination with the drilling force and the drilling speed, and their interactions, on the temperature rise were determined. The temperature rise in the bone under real conditions was measured as the implant site was being prepared by a dentist using intermittent, graduated drilling and external irrigation. Results show that the drill diameter has statistically significant effect, independent of the drilling procedure used. Among the examined drilling parameters, the drill diameter has the greatest effect, where an increase in the drill diameter first causes a decrease in the temperature rise and further increase in the drill diameter causes its increase. During the continuous and one-step drilling, the temperatures of the bones were up to 40.5 °C and during the drilling under actual conditions up to 30.11 °C.

Synthesis of Er- and Yb-doped gadolinium oxide polymorphs and influence of their structures on upconversion properties.

Nanocrystalline Gd(2)O(3) products doped with Er(3+) and Yb(3+) cations were synthesized by combustion method. We showed that the temperature of combustion can be tuned by using different types of organic fuels within reaction mixture. The combustion process is performed at lower temperature in the presence of urea as an organic fuel leading to pure cubic Gd(2)O(3):Er,Yb phase, on the other hand higher combustion temperature, yielding pure monoclinic Gd(2)O(3):Er,Yb polymorph is achieved in the mixture of urea and b-alanine. Effective doping of Er(3+) and Yb(3+) cations within Gd(2)O(3) were confirmed by XRD analysis. Both polymorphs show upconversion in green and red areas and possess strong dependence of fluorescence intensity ratios (I(525)/I(549) or I(525)/I(560) for monoclinic and cubic polymorphs, respectively) on temperature. This indicates that both phases can be applied for the temperature sensor devices based on upconversion intensity ratio changes.

Synthesis and fluorescent properties of chromium-doped aluminate nanopowders.

Nanocrystalline chromium-doped Al2O3 and MgAl2O4 products were synthesised by combustion method in the presence of urea. The powders were characterised by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), BET surface area analysis, induction coupled plasma analysis (ICP) and mapping energy dispersive X-ray analysis (EDX). Fluorescence properties of the products were investigated in order to find the applications in fluorescent sensor and in the production of transparent polycrystalline ceramic materials for laser and optical application.