Objective: Studies have demonstrated that restorative procedures can initiate pulpal inflammation. Adhesion molecules on endothelial cells mediate the leukocyte-endothelium interaction, which is the fundamental event of inflammation. The aim of this study was to evaluate possible changes in the endothelial cell adhesion molecules (CAMs) of human dental pulp with tooth preparation, and after the application of one-step self-etch adhesive. Materials and methods: Twenty healthy human premolars and third molars scheduled to be extracted for orthodontic reasons were randomly assigned to four experimental groups. Group 1 involved sound intact teeth representing the controls. In group 2, teeth were prepared for full crown and extracted within 2 h. Groups 3 and 4 comprised the teeth coated with one-step self-etch adhesive, iBond Gluma inside following the preparation and extracted after 24 and 48 h, respectively. Tissue distribution and staining intensity of CAMs including E-selectin, P-selectin, ICAM-1, VCAM-1 and PECAM-1 was investigated in the pulp samples using monoclonal antibodies and the streptavidin -biotin-horse -radish immunoperoxidase procedure. The assessment of immunohistochemical reactions was performed by two independent observers using a semi- quantitative scale. Results: All the CAMS evaluated were expressed by the healthy pulp tissues. Significant alterations in the distribution and staining intensity of CAMs were detected following tooth preparation. one-step self-etch adhesive tested in the present study induced inflammatory reactions in the pulp (P < 0.05, Mann-Whitney U-test). Conclusion: It seems evident that tooth preparation for full crown and application of onestep self-etch adhesive on prepared teeth had a potential to interfere with the inflammatory response. (C) 2007 Elsevier Ltd. All rights reserved.