The paper presents the numerical investigation with the purpose to find correlation between geometrical form of a guiding tooth and distribution of contact forces in the human masticatory system. The 3D computational model of masticatory system based on real geometrical data was built by means of LS-DYNA finite element software. The FEM analysis of simulated occlusal interference adjustment was performed. Results of numerical experiments showed that even minimal height of simulated occlusal interference on guiding surface of tooth 13 determined significant changes of magnitudes and directions of forces acting on the tooth and influenced its tendency for driftage; also caused changes in loading of the temporomandibular joint discs and alternated character of total forces acting on the whole maxillary dental arch.