Correlation between retention force of experimental plates and viscosity of experimental fluids

Introduction. Saliva viscosity plays a significant role in the biophysical segment of the total retention potential of total dentures. Objective. The aim of the paper was to establish the dependence of dynamic retention force of experimental plates on experimental fluid viscosity and especially time dependence of these parameters, following at the same time relative changes of the distance between the experimental plate and dentures support established by the dislocation of the experimental plate in both directions. Methods. For experimental verification we used an original device with the aim to enable in vivo simulation on the phantom made of the upper total denture prosthesis support and experimental plate. The experiment consisted of two parts. In the first part we determined the value of the dynamic retention force with plates without and with achieved ventilation effect. In the second part we determined time dependence of the dynamic retention force of experimental plates on the viscosity of experimental fluids that had been priorly determined on identical samples (8 ml of experimental fluid samples) using a rotational viscometer (Haake RV-12) with a sensor (MV, Germany). Results Under the conditions of variable viscosity rates of seven experimental fluids (from 0.02 to 1309.04 mPa•s), we registered the time dependence of dynamic retention force of the experimental plate related to fluid viscosity during the action of the continual dislocating force of the separating directions. In addition, the maximal height of the dislocation of the experimental plate was registered. The dynamic retention force, manifested by the separating direction of the experimental plate dislocation, was increased concurrently with increased viscosity. Conclusion. The increase of dynamic retention force depends directly on medium viscosity. Close border values of fluid viscosity above the investigated ones, the impossibility of experimental layer thinning and the decrease of distance height probably influence the onset of separating dislocation.