Alteration of odontoblast osteonectin expression following dental cavity preparation

Cavity preparation can increase the active synthesis and secretion of non-c ollagenous proteins by odontoblasts, thus resulting in the deposition of te rtiary dentine. In this study, the effect of cavity preparation on osteonec tin expression was examined in odontoblasts of the rat tooth pulp. A class V cavity was prepared in rat first molars to Stimulate odontoblastic secret ory activity, and the animals were killed at various intervals. In the norm al pulp, osteonectin immunoreactivity was detected in odontoblasts but not other cells. At I day after cavity preparation, immunoreactivity had dimini shed beneath the cavity. At 3 days, strong immunoreactivity could be detect ed in odontoblasts beneath the cavity. Numerous round cells underlying the odontoblastic layer also demonstrated immunoreactivity. Thereafter, the int ensity of osteonectin immunoreactivity in odontoblasts beneath tertiary den tine decreased gradually, and at 30 and 60 days, it was weaker than in norm al pulp. These findings suggest that osteonectin is actively synthesized by odontoblasts underlying a cavity in the initial stage of tertiary dentine formation. (C) 2001 Elsevier Science Ltd. All rights reserved.