Evaluation of monomer leaching from a resin cement through dentin by a novel model

- A new in vitro model for dentin permeability studies is presented.
- The model simulates the positive pulpal pressure of natural teeth, it is suitable for long term studies and requires no sophisticated equipment.
- Among all the constituents of the cement, only two compounds were able to diffuse through dentin in detectable concentrations.
- The amounts of HEMA that eluted through a 0.85 mm dentin disk under a pulpal pressure of 14.1 cm H2O, did not reach toxic levels for the pulp.

ObjectiveTo evaluate the elution of HEMA, BPA, UDMA and BisGMA from a conventional resin cement (Multilink Automix®, Ivoclar Vivadent) through human dentin, under constant positive pulpal pressure.MethodsTen human dentin disks (n = 10) were adjusted in a new testing device and transparent glass slabs were luted with Multilink Automix® resin cement, following manufacturer's instructions, under a steady pressure of 25 N. The device was filled with Ringer's solution. At 5 min, 20 min, 1 h, 2 h, 21 h, 3 days, 7 days, 10 days and 21 days time intervals, the whole eluate was retrieved from each one of the ten specimens and then, the specimens were refilled with fresh Ringer's solution. The eluates were analyzed by High Performance Liquid Chromatography (HPLC).ResultsHEMA was detected in the eluate of all of the specimens, from 5 min until 10 days. At four of the specimens, HEMA was also detected in the 21 days eluate at very low concentrations. BPA, UDMA and BisGMA were not detected at any eluate. An unknown compound was also detected at 4.4 min.SignificanceThe concentrations of HEMA that enabled to diffuse from Multilink Automix® cement in an aqueous solution, through a dentin barrier, did not reach toxic levels and BPA, UDMA and BisGMA were not detected at all.