Relationship between dentine hydraulic conductance and the cytotoxicity of four dentine bonding resins in vitro

Objectives. Dentine modifies pulpward diffusion of monomers leaching from restorative materials. Thus, remaining dentine thickness must be taken into account during in vitro cytotoxicity tests. This in vitro study was designed to determine the influence of dentine permeability on the outcome of a cytotoxicity test. Methods. Dentine slices were made from 36 human third permanent molar teeth. The 36 dentine slices were divided into two groups according to their hydraulic conductance: high or low hydraulic conductance. The cytotoxicity of four dentine bonding agents of similar cytotoxicity was tested on dentine slices from each group. Four dilutions of the experimental culture medium were tested: undiluted, 1:2,1:10 and 1:100. An analysis of variance was used to compare the cytotoxicity of the dentine bonding agents tested on high versus low hydraulic conductance. Results. The cytotoxicity of the high hydraulic conductance (Lp) group was higher than that of low Lp group when tested with the undiluted test culture medium (p = 0.001). No difference was obtained with the 1:2, 1:10, 1:100 dilutions. Conclusions. Under the conditions of the study, the dentine bonding resins were more cytotoxic when applied onto dentine slices of high hydraulic conductance.