Genetic predisposition to external apical root resorption in orthodontic patients

BACKGROUND: External apical root resorption (EARR) is an undesirable sequel of orthodontic treatment. The IL1-alpha had been pointed as a cytokine involved in the inflammatory process of the periodontal ligament during the orthodontic movement. OBJECTIVE: The aim of this study was to verify the association between polymorphism of the IL1-alpha gene and EARR after orthodontic treatment. MATERIAL AND METHODS: DNA was extracted from buccal epithelial cells of 61 unrelated individuals divided into two groups, according to the presence (n = 23) or absence (control group) (n = 38) of EARR on the upper central and lateral incisors after the orthodontic treatment. The polymorphism was analyzed by the polymerase chain reaction (PCR) method, followed by restriction enzyme digestion (RFLP). RESULTS: Statistical significant differences (p < 0,05) were found on the frequency of the alleles and genotypes from polymorphism of the IL1-alpha gene between case and control groups, suggesting that allele 2 predispose the individual to EARR and individuals with 2/2 genotype had almost 3 times more chance to present EARR than 1/1 or 1 /2 genotype individuals (OR = 2,9). CONCLUSION: The studied polymorphism was associated with external apical root resorption post orthodontic treatment in the studied population.