Application of branched urethane-methacrylic resins for dental composites
Mikołaj Szafran, Gabriel Rokicki, Lidia Czerwińska, Ewa Bobryk Politechnika Warszawska, Wydział Chemiczny, ul. Noakowskiego 3, 00-664 Warszawa, Poland
Quarterly No. 1, 2008 pages 47-52
DOI:
keywords: dental composites, urethane-methacrylic resin, camphorquinone, barium sulphate
abstract In this study, the preliminary results of investigations concerning the influence of the amount of camphorquinone (the photoinitiator) on the photopolymerization process and the influence of barium sulphate content on the mechanical properties of the composites for dental applications were presented. In order to examin composites’ properties, such as Vicker’s microhardness, bending strength the samples containing micro- and nanosilica fillers as well as barium sulfate were prepared. To investigate the ceramics-polymer binding the fractures of the cured composite were analyzed. X-ray the pictures of the samples containing different amounts of BaSO4 were presented. The higher concentration of BaSO4, the larger X-ray contrast is visible. It can be noticed that the method of the powder mixing influenced X-ray contrast. Ball milling of the ceramic powder with water (ratio 1:1) leads to more homogeneous composites. The X-ray contrast of the sample with BaSO4 was compared with the reference sample (80% SiO2, 20% K3M). It can be seen that the addition of BaSO4 causes, that the mass has a better X-ray contrast. The investigation of Vicker’s microhardness of composites of A series showed that optimal content of BaSO4 is 10 wt. %. However, considerable influence of the presence of BaSO4 on bending strength was observed. The bending strength of the composites falls down with the growth of the content of BaSO4. It was shown that with the increase of the amount of the initiator in the composition, the microhardness and bending strength of the composites rises. However, for higher amount of camphorquinone the color of the composites becomes more yellow.