engleski

Application of Ion Chromatography for Monitoring of Chemical Stability of Dental Chermics in acidic Solution

Dental ceramics are generally composed of a majority of silica (SiO_2) and commonly contain oxides of Na, K, Ca, Mg, Al and colorant oxides. The degradation of dental ceramics in the oral environment generally occurs because of chemical attack (corosive process), mechanical forces, or a combination of these effects. The corosive process of the dental alloys is very well known but little information is available on the corrosion of dental ceramics. We have investigated the chemical stability of the dental ceramics in an acid medium. Samples of feldspathic ceramic (IPS Classic) on Co-Cr and Ni-Cr alloys and hydrothermal ceramic (Duceragold) on the high-noble gold alloy were deposited in 10-3 mol/L HCl at 50 ˆoC for 1, 2, 3 and 6 monts. After each interval time solution analyses were performed by means of a pH-meter and Ion Chromatography (IC). Traditional methods to determination of Naˆ+, Kˆ+, Caˆ2+ and Mgˆ2+ such as AAS are beeing replaced by IC techniques, more simple and rapid. The Naˆ+, Kˆ+, Caˆ2+ and Mgˆ2+ were separated using 4 mmol/L tartaric acid/1 mmol/L dipicolinic acid as eluent, and were measured by a conductivity detector. For analysis was used a 690 Ion Chromatograph (Metrohm) with Metrosep Cation Column 1-2. The weight losses of the samples were measured by analytical scales. Our results showed that the most of ions were eluted after 1th, 2nd and 3th month, while after the 3th month the elution was significantly lower in each sample. The most significant elution and the higher weight loss showed the sample with the hydrothermal ceramic. The pH values were changed in each leachate samples after 1th, 2nd and 3th month, but stabilized after the 3th month of the investigation. The results of our investigation showed that dental ceramics are not indifferent toward the acid medium

ion chromatography; dental cheramics; chemical stability

nije evidentirano