Hydroxyapatie for already more than thirty years has been used as substitute for natural bone. This material for that purpose is selected due to its similarity with natural Hydroxyapatie (NAHp) which is found in hard biological tissue. Unfortunately hydroxyapatite also has disadvantages - this material is brittle and also its modulus of elesticity, ultimate stress and ultimate strain differs considerably from these parameters for natural hard tissue. Due to these disproportions pure hydroxyapatite has limited load bearing applications as bone substitute in practical medicine. In order to improve mechanical properties hydroxyapatite is combined with different supplements. In our work we have chosen endodentine cement (EC) for this purpose. EC has quick setting time and acceptable mechanical properties. This material solidifies within approximately ten-fifteen minutes. Moreover in our work instead of synthetic hydroxyapatie we have used NAHp which is obtained from natural bone by heat processing. NAHp is chosen because after heat treatment it contains natural microstructure that fosters integration with live natural bone tissue.