The effects of repetitive firing processes on the optical, thermal, and phase formation changes of zirconia

PURPOSE: The aim of this study was to investigate the effect of different numbers of heat treatments applied to superstructure porcelain on optical, thermal, and phase formation properties of zirconia.MATERIALS AND METHODS: Forty zirconia specimens were prepared in the form of rectangular prism. Specimens were divided into four groups (n = 10) according to the number of firing at heating values of porcelain. Color differences and translucency parameter were measured, and X-ray diffraction (XRD) analysis and differential scanning calorimetry (DSC) were performed. Data were analyzed with analysis of variance (ANOVA).RESULTS: There were no statistically significant differences in ΔE, TP, L, a, and b value changes of the zirconia specimens as a result of repetitive firing processes (P>.05).CONCLUSION: Although additional firing processes up to 4 increase peak density in thermal analysis, additional firing processes up to 4 times can be applied safely as they do not result in a change in color and phase character of zircon frameworks.

Comparison of the effectiveness of intravenous piracetam and intravenous dimenhydrinate in the treatment of acute peripheral vertigo in the emergency department

<p><b>INTRODUCTION</b>We aimed to compare the effectiveness of intravenous piracetam with that of intravenous dimenhydrinate in the treatment of acute peripheral vertigo in the emergency department.</p><p><b>METHODS</b>This double-blind study comprised a total of 200 patients, aged between 18 and 70 years, who had presented to the emergency department of Ankara Training and Research Hospital and were diagnosed with peripheral vertigo. Evaluation of the severity of the patients' vertigo was performed using a visual analogue scale, before and after drug administration.</p><p><b>RESULTS</b>Both drugs were found to be effective (p < 0.001) and had comparable effects (p < 0.474). Dimenhydrinate was also found to have about two times the side effects of piracetam. Drowsiness was found to be the most common side effect of these two drugs.</p><p><b>CONCLUSION</b>Dimenhydrinate and piracetam have similar levels of effectiveness with regard to acute vertigo. We conclude that piracetam, which has fewer side effects than dimenhydrinate, better vestibular compensation, and is effective for both acute and chronic vertigo, could be more frequently used in the emergency treatment of acute vertigo.</p>