Human interleukin-1 beta and interleukin-1 receptor antagonist secretion and velocity of tooth movement

The cytokines interleukin-1 beta (IL-1 beta) and IL-1 receptor antagonist ( IL-1RA) probably play a part in orthodontic tooth movement. Here, the force magnitudes and the area of force application in the compressed periodontal ligament (PDL) were controlled and the velocity of tooth movement correlat ed with concentrations of IL-IB and IL-IRA in the gingival crevicular fluid (GCF). Seven individuals undergoing orthodontic treatment involving maxill ary first premolar extractions and distal movement (bodily retraction) of t he maxillary canines participated in the 84-day study. For each participant , continuous retraction forces were applied so that they received equivalen t PDL stresses of 13 kPa for one canine and 4 kPa for the other. GCF cytoki ne concentrations from experimental and control teeth were expressed relati ve to total protein in the GCF and compared using an 'Activity Index' (AI) = Experimental (IL-1 beta /IL-1RA)/Control (IL-1 beta /IL-1RA). The results showed that the velocity of tooth movement in an individual was related to their At. The correlation between AI and tooth movement was stronger from the distal (R-d = 0.78) than from the mesial (R-m = 0.65) of retracted teet h. The results demonstrate that equivalent force systems produce individual differences in cytokine production, which correlate with interindividual d ifferences in the velocity of canine retraction. (C) 2001 Elsevier Science Ltd. All rights reserved.