Objective. To study the hydrodynamics of the dentinal fluid along the dentinal tubule in the event of its opening as a result of mechanical and acid treatment of the dental crown dentin. Material and methods: A licensed version of the ANSYS / FLOTRAN computer program was used, which is a software tool for solving various problems of hydrodynamics, including laminar and turbulent flow of an incompressible or compressible fluid. Results. The results of computer simulation showed that 1.5 ms after drying of the dentin tubule (length 6 mm) it is refilled with dentin fluid, which then begins to accumulate on the treated surface of the dental hard tissues. Reducing the length of the dentinal tubule as a result of the cavity preparation leads to an increase in the speed and mass of pulp fluid released through it.