Uptake, clearance and metabolism of TEGDMA in guinea pigs

Objective. The resin monomer triethyleneglycoldimethacrylate (TEGDMA) is used as a diluent in many resin-based bonding, cementing and direct tooth filling materials. Methods. In the present study the uptake and the clearance of 14C-TEGDMA applied via different routes were examined in vivo in guinea pigs. TEGDMA (0.02 mmol/kg by weight labeled with a tracer dose 14C-TEGDMA 0.7 Bq/g by weight) was administered by gastric tube or by subcutaneous injection. Urine, feces, and exhaled carbon dioxide were collected for 24 h after administration. The animals were killed 24 h after the beginning of the experiment and various organs removed and 14C-radioactivity measured. Results. It was apparent that 14C-TEGDMA was taken up rapidly from the stomach and small intestine after gastric administration and was widely distributed in the body following administration by each of the routes. Clearance from most tissues following gastric and intradermal administration was essentially complete within one day. Low fecal 14C-levels (<1% of the administered dose) and urinary levels of about 15% after 24 h were noted with each route of administration. Direct measurement of exhaled carbon dioxide showed that 60–65% of the administered dose of 14C left the body via the lungs during 24 h. It is likely that 14C-pyruvate is formed in vivo resulting possibly in the formation of toxic 14C-TEGDMA-intermediates. Significance. Despite using a high administered dose, the peak TEGDMA levels in all tissues examined after 24 h were at least 100,000-fold less than known toxic levels.