The presented paper is mainly focused on nanoindentation of damaged human teeth, which have been treated with amalgam fillin g and describing the micromechanical properties (reduced elastic modulus Er and hardness H). The analysis was carried out on two samples of tooth no. 37, the first from a woman (48 years old) and the second from a man (26 years old). For both teeth was the main cause of the extraction an advanced stage of periodontitis chronica. The provided treatment of the tooth decay has been realized using amalgam filling with a different depth of cavity drilling. Within the analysis, we have made a series of indentation experiments in the transversal sections of the teeth. In these sections, we have measured the mechanical properties in individual dental materials for the sake of determining the influence of the degradation of dentin damaged by tooth decay. The differences of micomechanical parameters occur in the dentin area (Er ≈ 7.6 GPa in the dentin-amalgam interface and Er ≈ 30.2 GPa in the center of the dentin wall). Lesser variance of values is present in the enamel area, where the difference is less than 11 % in the enamelamalgam interface.