Association of functional gene polymorphism IL-1β in patients with external apical root resorption

Introduction: External apical root resorption (EARR) is a frequent complication of orthodontic treatment. Interleukin 1 beta (IL-1 beta) is a potent stimulus for bone resorption and osteoclastic cell recruitment during orthodontic tooth movement. The purpose of this study was to assess the association between a polymorphism in the IL-1 beta genes and EARR during orthodontic treatment. Methods: The sample included 61 Brazilian orthodontic patients, divided into 2 groups according to the presence (affected group, n = 23) or absence (control group, n = 38) of EARR in the central and lateral maxillary incisors in the posttreatment period. DNA was obtained from buccal swab cells. The polymorphism was analyzed by the polymerase chain reaction followed by digestion with restriction enzyme. The polymerase chain reaction products were analyzed in 10% polyacrylamide gel and stained with silver. Results: There were significant statistical differences (P<0.05) among the frequencies of the alleles and genotypes of the IL-1 beta gene polymorphism between the affected and unaffected groups, suggesting that allele 1 predisposed the subjects to EARR (odds ratio = 4.0). Conclusions: The polymorphism of the IL-1 beta gene is associated with root resorption in the studied population. (Am J Orthod Dentofacial Orthop 2009;136:542-6)