ABSTRACT
In this paper, an attempt was carried out to produce calcium phosphate ceramics whose composition comes close to that of natural dry bone. Dicalcium phosphate dihydrate [CaHPO4.2H20] and calcium carbonate [CaCO3] were mixed at different proportions so that three batches of ceramics whose Ca/P ratio are 1.5, 1.7 and 1.9 are obtained. These ratios lie in close vicinity to the reported data for dry cortical bone [Ca/P =1.67]. Sintering was carried out at temperatures ranging from 1100 to 1350°C. The variation in batch composition as well as in sintering temperature has proved to play a decisive role in determining the end product characteristics. Parameters such as bulk density, porosity, firing shrinkage, modulus of mechanical rupture, mineralogical and textural features and thermal expansion behavior, were studied to assess their matching with those of dry cortical bone
ABSTRACT
For most biomedical measuring devices noninvasive techniques are not only favorable but also necessary to monitor the actual function of the investigated organ under realistic conditions. One of the major problems concerning in vivo measurements of mechanical forces distribution over the month cavity: is that monitoring these forces as they develop usually interferes with the chewing process itself. In this work we present an implantable electronic device which call be molded in the denture so that it measures the stress distribution on the denture under different conditions. The device is provided with strain gauges that modulate the frequency output, hence the strain can be evaluated remotely while the actual mastication undergoes without interruption. The device is activated externally so that no battery is needed to provide the required power. The data is received and connected to a computer to analyze the stress distribution for more than one location. The results showed the validity of such technique and the implications are discussed