Do resin-based composite CAD/CAM blocks release monomers?

Objective The present study aimed to identify and quantify the elution of monomers of five different resin-based CAD/CAM blocks (RCBs) using HPLC. Methods Five different RCBs were used in the study: GC Cerasmart (CS), Voco Grandio blocs (GR), 3M Lava Ultimate (LU), Shofu Block (SB), and Vita Enamic (VE). Fifteen samples from each material were prepared using a low-speed precision diamond saw (ISOMET Buehler, Lake Bluff, IL, USA) at 5 x 5 x 4 mm size. After the preparation of samples, an extraction solution was mixed with %75/%25 ethanol/water. The samples were stored in the amber-colored bottles during three different immersed periods as 1 h, 24 h, and 90 days (n = 5). After immersion, 0.5 ml solutions were taken from each bottle and analyzed using HPLC. Results A total of 16.7 mu g/ml of monomers from SB, 13.4 mu g/ml of monomers from GR, 13.2 mu g/ml of monomers from CS, and 6.7 mu g/ml of monomers from LU were found after 3-m immersion. TEGDMA after 3-m of immersion was only released from the SB group, and also BisEMA was released from the CS group. Among the specimens immersed for 1 h, UDMA was released the least from the LU group and the most from the GR group (p < 0.05). Correspondingly, 24 h and 3 m after immersion, the highest release of monomers was found in the GR (p < 0.05). Conclusions When the monomer release from RCBs was evaluated, it was shown that these materials released methacrylate-based monomers except VE, especially if they were kept in a solvent solution for a long time such as 3 m. Clinical significance The novel resin-based CAD/CAM blocks might monomer release, which may cause cytotoxic effects. But, the detected amount of monomer release is below the estimated daily limit.