RESUMO
AIM: To investigate the association of clinical variables and polymorphisms (tag SNPs) in the interleukin 4 (IL4) gene, with the prognosis of avulsed and replanted teeth. METHODOLOGY: Ninety-four patients who suffered avulsion and had their teeth replanted and endodontically treated were included. Periapical radiographs were obtained soon after tooth replantation and after 1 year. For genotypic IL4 gene analysis, the DNA from oral mucosa cells was collected, and polymorphisms were investigated by real-time PCR. Univariate and multivariate analyses were performed to verify the association of clinical and genetic variables and the outcome of the replanted teeth (P < 0.05). RESULTS: After multivariate analysis, extra-alveolar time longer than 1 h was significantly associated with external root resorption. No significant association was observed between IL4 gene polymorphisms and root resorption. CONCLUSION: No association between root resorption and IL4 gene polymorphisms was observed. An extra-alveolar time of more than 1 h was associated with a susceptibility for external root resorption. Replanting the tooth in its socket immediately is the most important factor to maintain a healthy root surface.