Evaluation of IL-1 B (+3954) Gene Polymorphism and External Apical Root Resporption Associated with Orthodontic Treatment

Abstract

The purpose of this prospective study was to examine the external apical root resorption (EARR) status and genetic marker composition of 100 Caucasian patients (59 females and 41 males) who have undergone orthodontic treatment at the private practice office of Dr. James V. Macri. A diallelic polymorphism marker for IL-1B +3954 within the candidate gene IL-1B was used to investigate the difference in relative risk for EARR. EARR measurements taken on pre and post treatment occlusal radiographs were then used to determine any association with genotype. Using linear regression analysis, length of treatment, overjet and molar classification were found to be significant predictors of EARR (p<0.05). The findings indicated that increased length of treatment or overjet is associated with increased EARR. Furthermore, those subjects with a class II molar classification were less likely to experience EARR compared to those with either a class I or class III molar classification. An ANOV A test was performed to examine the relationship of the IL-1B marker with the dependent variable EARR. There was no statistically significant association between the IL-1B genotype and EARR (p=0.53). Finally, a chi-square test was used to evaluate the association of the IL-1B genotypes in the affected (>5mm EARR) and unaffected (<5mm EARR) groups. There was no significant association between affection status and the IL-1B genotype (p=0.87).