Journal of Dental Research, Vol 67, 1092-1096, Copyright © 1988 by International & American Associations for Dental Research Online Journals
In vivo and in vitro effects of zinc oxide-eugenol (ZOE) on biosynthesis of cyclo-oxygenase products in rat dental pulp
S. Hashimoto, K. Uchiyama, M. Maeda, K. Ishitsuka, K. Furumoto and Y. Nakamura
Department of Endodontics, School of Dentistry, Nippon Dental University, Tokyo, Japan.
To determine the in vivo effects of a zinc oxide-eugenol mixture (ZOE) on
the cyclo-oxygenase system in dental pulp, we used radioimmunoassay to
measure the levels of prostaglandin E2 (PGE2), 13,14-dihydro-15-keto-PG
(DHK-PG), thromboxane B2 (TXB2), and 6-keto-PGF1 alpha in the dental pulp
of rats. When the dental pulp was irritated by a hole made in the dentin of
the mandibular incisors without use of any coolants, the levels of these
cyclo-oxygenase products in the pulp were increased to, respectively, 2.8,
1.7, 10.0, and 2.6 times those in the normal pulp at six hr after
treatment. In contrast, these increases in cyclo-oxygenase products
disappeared immediately when the artificial cavity in the dentin was filled
with ZOE (P/L; 1 g/0.25 mL), but were not altered when the cavity was
filled with zinc oxidewater (ZOW, 1 g/1.5 mL). Most of the eugenol portion
of ZOE was released into the pulp within two hr after the cavity was filled
with ZOE. The maximal eugenol content was 35 pmol per mg of pulp.
Furthermore, when the cavity was filled either with ZOE or by the addition
of 10 mumol/L eugenol to the pulp homogenate, biosynthesis of
14C-6-keto-PGF1 alpha, PGF2 alpha, and PGE2 from 14C-arachidonic acid in
the homogenate was inhibited. These results suggest that eugenol released
from ZOE in the cavity prepared in the dentin inhibited the biosynthesis of
cyclo-oxygenase products during pulp irritation.
