In the first part of this study some physical properties of restorative materials, amalgam, glass-ionomer and composite resin were measured experimentally. In the second part a numerical study was carried out, for which the maxillary second premolar tooth was used. The tooth model was restored with composite resin and amalgam on glass-ionomer, which was used as the base material. The stress distribution investigated was the resultant of the stresses which come from the mastication force and those resulting from the contraction and expansion of restorative materials. All calculations were carried out using the finite element method and programs were written using FORTRAN 77. A load of 450 N, at an angle of 45 degrees to the longitudinal axis was applied on the occlusal margin of the tooth. The tooth was assumed isotropic, homogenous, elastic and unsymmetrical. The distribution of compressive, tensile and shear stresses were plotted for the whole tooth structure.