Elution study of unreacted TEGDMA from bulk-fill composite (SDR™ Dentsply) using HPLC

The study evaluates the dynamics of unreacted TEGDMA monomer elution from new generation of flowable bulk fill composite resin (SDR™ Dentsply).

Polymerised specimens of SDR™ composite (7mm diameter and 4mm thick) were placed in four solutions: 100% ethanol, 75% ethanol, distilled water and 100% methanol. The concentration of the eluted TEGDMA was measured using the HLPC method after 0.5, 1, 2 and 3h as well as after 1, 3, 7, 14, 21 and 31 days.

During the first 24h of storage in each medium, a significant elution of TEGDMA was observed (100% ethanol - 12.5μg/g, 75% ethanol - 8.4μg/g, distilled water - 5.4μg/g and 100% methanol - 7μg/g). The elution time of the TEGDMA into 100% ethanol, 75% ethanol, distilled water and 100% methanol was 14, 7, 3 and 1 day, respectively. After 31 days, total concentrations of TEGDMA were as follows: 100% ethanol - 16μg/g, 75% ethanol - 9.4μg/g, distilled water - 6μg/g and 100% methanol - 7μg/g.

The TEGDMA was released from the SDR™ composite into each solution used. The TEGDMA concentration and the time of its elution depend on the type of the solvent. In an aqueous environment, the SDR™ composite exhibits a high chemical stability compared to other solutions. The direct toxicity towards to the dental pulp is established during the first hours after the placement of resin.