Release of methacrylic acid from dental composites

The aim of this study was to investigate the release of methacrylic acid from four commercial dental composite restoratives (Silux Plus (3M), Z100 (3M), Ariston pHc (Vivadent) and Surefil (Dentsply)).

Three specimen disks (10(0.2) mm in diameter and 2(0.2) mm thick), were prepared for each material using custom-made molds. Each disk was placed in artificial saliva for 24 h at 37 degrees C, rinsed and subsequently immersed in 1.5 ml of deionised water in an airtight glass container. The container was continuously shaken at a speed of 80 rpm for 24 h at 37 degrees C in an orbital incubator. After 24 h (Day 1), the water was removed and analyzed. The specimen disk was then re-immersed into another 1.5 ml of fresh deionised water. The procedure of removing and refilling of the water was repeated for a total of 7 days. The sample solutions were filtered and injected into the capillary electrophoresis system for analysis immediately after collection. Statistical analysis was performed by ANOVA and Scheffe's test.

For Days 1-7, methacrylic acid released in water at 37 degrees C by Ariston was significantly greater than that of the other composites. Ranking from least to greatest total (cumulative over 7 days) methacrylic acid release was as follows: Z100 (5.66 ppm) < Silux (8.81 ppm) < Surefil (20.21 ppm) < Ariston (519.04 ppm). Methacrylic acid release was greatest at Day 1 for all materials and generally decreased with time.

Some composites may release high levels of methacrylic acid. The biological effects of such high levels of methacrylic acid is not known and warrant further in vivo and in vitro investigations.