Periodontal cytokines profile under orthodontic force and extracorporeal shock wave stimuli in a rat model

Background and ObjectiveExtracorporeal shock wave therapy has been used in various clinical conditions as a result of its ability to stimulate healing processes in acute and chronic inflammatory states. Orthodontic force application triggers an inflammatory reaction in the periodontal tissue surrounding the involved teeth, resulting in tooth movement. Preliminary work revealed that extracorporeal shock wave therapy increased the expression of the inflammatory cytokines involved. Our aim was to investigate the expression of inflammatory cytokines in the periodontal tissues following orthodontic force induction, with and without shock wave therapy, in experimental rats. Material and MethodsAn orthodontic appliance was fabricated and applied between the molars and the incisors of adult Wistar rats. In conjunction with orthodontic force commencement, the rats were treated with a single episode of 1000 shock waves. Every day, during the 3d of the study, rats were killed and the immunolocalization of RANKL, interleukin (IL)-1, IL-6 and tumor necrosis factor-alpha was evaluated. ResultsThe percentage of the area staining positively for all inflammatory cytokines during the first 2d decreased statistically significantly more in the shock wave-treated group compared with the nontreated control group. On the first day, the percentage of the area staining positively for IL-1 and RANKL on the compression side peaked in both groups, with a sequential rise in the number of TRAP-positive cells. ConclusionThe induction of shock wave therapy during orthodontic tooth movement influences the expression of different inflammatory cytokines in the tissue and might alter the expected periodontal remodeling rate.