Ceramic-polymer composites for permanent fillings - influence of ceramic particles on mechanical properties
Małgorzata Lewandowska*, Mariusz Andrzejczuk*, Joanna Karaś**, Mikołaj Szafran***, Gabriel Rokicki***, Krzysztof J. Kurzydłowski* *Politechnika Warszawska, Wydział Inżynierii Materiałowej, ul. Wołoska 141, 02-507 Warszawa **Instytut Szkła i Ceramiki, ul. Postępu 9, 02-676 Warszawa ***Politechnika Warszawska, Wydział Chemiczny, ul. Noakowskiego 3, 00-664 Warszawa
Annals 4 No. 11, 2004 pages 302-305
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abstract Until quite lately, an amalgam was the main material used for permanent fillings in dentistry because of its good mechanical characteristics and good adhesion to the tooth tissue. However, its disadvantages e.g. toxicity of mercury vapour, high thermal conductivity, as well as unsatisfied colour of fillings, motivate to widespread investigations of new materials which could replace the amalgam. In the group of various materials the composites seems the most perspective. The aim of this work was to develop ceramic-polymer composites for permanent fillings in dentistry and in particular to study the influence of ceramic particles on their mechanical properties. Bis-GMA resin was used as polymer matrix. Ceramic glasses with different chemical compositions, shown in Table 1, were used as composite fillers. They differ in particle size distributions (Table 2), what is important in the context of their effect on mechanical properties of composites. Examples of the microstructures of the fabricated composites containing 60 vol.% of fillers are shown in Figure 1. They are homogenous that was confirmed also by the results of microhardness measurements. Microhardness distribution of the fabricated composite (Fig. 2) was similar to that of commercial composites. The mean values of microhardness of the composites with various fillers are shown in Figure 3. The composite with ceramic glass containing La2O3 has exhibited the highest microhardness. However, the chemical composition of the filler has a minor effect on material properties. The strong correlation between the microhardness and the size of particles (Fig. 4) and the microhardness and the volume fraction of filler particles (Fig. 5) have been found. Key words: ceramic-polymer composites, dental fillings, microstructure, mechanical properties