[Evaluation and identification of colors used in dentin porcelain and determination of laboratory production method for colored dentin similar to Vita VMK68 dentin]

Since there are rich mines of porcelain in Iran, dental porcelain production has been considered. Dentin porcelain was produced in previous projects. Color plays an important role in dental porcelain therefore, the aim of the present study was to identify different colors used in VitaVMK68 dentin porcelain and produce the similar porcelain in Iran and compare the quality and quantity of the produced colored samples with Vita samples. In this technical report, the best firing conditions was determined by XRD device. Dentin powder structure was evaluated by SEM. Chemical compound analysis and identification of colored particle found in Vita porcelain powder was done by different methods. In order to make colored dentin samples, compound colors with different formula and percentage, was added to dentin powder and after providing a homogenous compound, they were pressed and put in vita furnace for firing. The color of new dentin was examined with colorimeter and compared with vita dentin. 1] The results of X-Ray diffraction showed complete conformity of different phases in experimental dentin powder with Vita dentin powder. 2] Experimental dentin powder particle size was very similar to Vita dentin powder. 3] The main colors used in Vita dentin powder had crystalline structure and were the same as ceramic stains. 4] Sintered experimental colored dentin samples showed acceptable similarity to sintered Vita dentin samples [according to delta E]. Experimental colored dentin samples showed acceptable similarity to Vita dentin samples with no clinically perceptible color differences

[Invitro evaluation of cytotoxicity and elemental release of three types of nickel-chromium basemetal alloys and comparison with one type of high noble [gold-palladium-silver] alloy]

Dental alloys following corrosion cause changes in oral tissues. As base metal alloys are used for fabrication of dental prostheses and are manufactured in Iran, the aim of this study was to investigate the cytotoxicity of three types of nickel-chromium base metal alloys with one type of high noble alloy on mouse fibroblast cell [L 929] by MTT test. In this experimental study, 12 disks of each alloy with 5mm diameter and 2.5 mm thickness were prepared and placed in RPMI culture medium for 48 hours and 72 hours [extract medium]. Then the extract mediums were diluted in two different dilutions of 200 micro 1 and 40 micro 1 and their cytotoxicity were evaluated by MTT assay and compared with two control groups consist of only culture media and culture media with teflon. The amount of Nickel, chromium, copper, zinc and silver released from each alloys were measured by flame atomic absorption device. The data were analyzed by Graph Instat software, one way ANOVA and Tukey tests. After 48 hours, no significant difference in cytotoxicity was found between samples and control groups. After 72 hours there was a significant difference between samples and control groups [Minalux vs. Control: P<0.01, Degubond vs. Control: P<0.001, Wiron 99 vs. Control: P<0.001, Supercast vs. Control: P<0.05] There was no significant difference in cytotoxicity with two dilutions of 200 micro 1 and 40 micro 1 between samples. Maximum release of nickel and chromium were observed from Minalux, silver from Degubond and zinc Supercast. The cytotoxicity of three Nickel-Chromium alloys and one high noble which were used in this study was not different. Cytotoxicity increased with time