Release of monomers in dental wastewater during treatment. A comparative in vitro and in vivo study based on Fabric phase Sorptive extraction

Abstract

The main objective of this research was to detect monomers that are released during dental restorative procedures related to the oral cavity and then discharged into the environment through the drainage of the dental unit. This study involves the collection of wastewater from the spray system of a high-speed dental handpiece before it winds up in the central drain after the grinding of resin composite materials. The study was executed in two phases: an in vitro experiment and an in-vivo experiment. Three representative dental materials were used; a resin composite for direct restorations, a core-build up material, and a computer-aided designand computer-aided manufacturing (CAD/CAM) material. On both occasions, the water from the spray-system of the handpiece during the milling of the specimens was extracted using water suction and analysed by high-pressure liquid chromatography (HPLC) and verified with HPLC-PDA after Fabric Phase Sorptive Extracttion. In the first phase, triethylene glycol dimethacrylate (TEGDMA) was detected in the wastewater samples of all the materials tested whereas bisphenol-A (BPA) was not detected. Urethane dimethacrylate was released only from the CAD/CAM material (0.66 ± 0.14 ng/μL) while BisGMA was not detected. In the second phase the core build-up material released an amount of BPA (0.42 ± 0.14 ng/μL) while after 7 days, the amount of BPA increased (0.97 ± 0.07 ng/μL). The resin composite indicated for direct restoration material released the highest amount of TEGDMA (p < 0.001).The contamination of the environment by dental procedures is possible because monomers are released from different dental restorative materials and are detected in the wastewater of dental units.