Expression of Inflammatory Cytokines and Chemokines in Replanted Permanent Teeth with External Root Resorption

The progressive forms of inflammatory external root resorption (IERR) and replacement external root resorption (RERR) are serious complications and the main causes of tooth loss after replantation. This study aimed to investigate the expression pattern of inflammatory molecules in extracted human teeth presenting with external root resorption (ERR) after replantation.

Root fragments from 22 teeth showing IERR and 20 teeth with RERR were triturated using a homogenizer to extract inflammatory molecules. Interleukin-1β (IL-1β), IL-1Ra, transforming growth factor beta, IL-8/CXCL8, CCL2, CCL3, and CCL5 were measured using double-ligand enzyme-linked immunosorbent assay, and IL-2, IL-4, IL-6, IL-10, tumor necrosis factor alpha, interferon gamma, and IL-17A detection was performed using the multiplex Th1/Th2/Th17 Cytometric Bead Array kit (BD Biosciences, San Jose, CA). Cytokine and chemokine concentrations were compared in the RERR and IERR groups corrected by patients' age at the moment of extraction, survival time after replantation, and index of ERR, adopting a generalized estimation equation model.

The IERR group showed higher levels of tumor necrosis factor alpha than the RERR group, even after correction for the index of ERR (P < .05). IL-1Ra levels were higher in the IERR group for moderate cases but higher in the RERR group for severe cases (P < .05). IL-4 concentration became higher with the increase of patients' age in the RERR group but did not vary in the IERR group (P < .05). CCL2 levels decreased with the increase of the patients' age at the moment of extraction irrespective of the type or index of ERR (P < .05).

The present results showed differences in the immunologic profile of IERR and RERR that may be relevant to understanding the biological mechanisms underlying ERR.