Thermal expansion of hydroxyapatite between-100 °C and 50 °C

Hydroxy apatite (HAp) ceramic was synthesized using traditional sintering. Dilatometric and lattice thermal expansion properties of a HAp ceramic were evaluated at temperatures of - 100-50 degrees C. In that temperature range, the dilatometric thermal expansion coefficient and the lattice thermal expansion coefficient of the HAp ceramic were, respectively. 10.6 x 10(-6)/degrees C and 9.9 x 10(-6)/degrees C. Furthermore. thermal expansion properties of a human tooth were measured. The thermal expansion coefficient of the horizontal direction perpendicular to the growing direction of a tooth was 15.5 x 10(-6)/degrees C; that of the vertical direction along with the direction of tooth growth was 18.9 x 10(-6)/degrees C at the temperature range described above. (C) 2008 Elsevier B.V. All rights reserved.