Concentration of eugenol apically released from zinc oxide-eugenol-based sealers

This study investigated the amount of eugenol released from a zinc oxide-eugenol-based sealer at the apex of teeth filled according to two techniques: the single-cone and the Thermafil. The crown of 10 maxillary central incisors was removed, and the canal was prepared with ProFile to a size 30 under NaOCl irrigation. The patency of the apex was checked with a #8 K-file between each ProFile. Five roots were filled with a Thermafil #30 and 0.03 g of Sealite; five roots were filled using a Lentulo with 0.07 g of sealer and a gutta-percha cone #30. The powder/liquid ratio of the sealer was of 5/1. The concentration of eugenol released in phosphate-buffered saline was spectrofluorimetrically determined immediately after sealing, after 1 day, and after 1 month of storage. The roots filled with the single-cone technique released significantly more eugenol than these filled with Thermafil immediately after sealing (p = 0.002); but, after 1-day or 1-month storage, there was no difference. For both techniques, eugenol concentration decreased over time (p = 0.01): the immediate concentration was higher than the 1-day concentration (p = 0.04). Eugenol concentration after 1-month storage was undetectable. The results of this work show that the level of eugenol released from a zinc oxide-eugenol-based sealer beyond the apex is very low and decreases over time.