title: Effects of continuous and interrupted orthodontic force on interleukin-1beta and prostaglandin E2 production in gingival crevicular fluid.
abstract: The purpose of this study was to evaluate the effects of a light continuous force and an interrupted force with weekly reactivation on interleukin-1beta (IL-1beta) and prostaglandin E(2) (PGE(2)); possible interactions between these 2 potent mediators of the bone resorption process were assessed in vivo. Ten healthy young adults (mean age 20.6 years, 2 men, 8 women) with 4 premolars extracted were assessed. In each subject, 1 maxillary canine (E1) received continuous force with a nickel-titanium coil spring. The opposite canine (E2) received an interrupted force with a screw-attached retractor; the force was reactivated weekly by 2 turns of the screw. An antagonistic canine was used as a control. Gingival crevicular fluid was collected from the distal side of each tooth, 10 times in 3 weeks, and IL-1beta and PGE(2) levels were measured. For E1, the IL-1beta level showed a significant elevation at 24 hours and then decreased and maintained an insignificant but high mean concentration, compared with the control site. The PGE(2) level showed a significant elevation at 24 hours and then decreased. For E2, a significant elevation of IL-1beta level was observed at 24 hours and a greater significant elevation at 24 hours after the first reactivation, compared with the control sites. The PGE(2) level increased significantly at 24 hours and remained high for 1 week. The synergistic up-regulation of PGE(2) by appliance reactivation and secreted IL-1beta was not evident with either type of force after 1 week. Both experimental sites showed significant tooth movement compared with the control sites at 3 weeks; however, there was no significant difference between the 2 experimental sites. A well-controlled mechanical stress with timely reactivation can effectively upregulate IL-1beta secretion, but there might be limitations in increasing the mediator levels, because of the feedback mechanisms in vivo. In addition, the analysis of crevicular fluid is a useful method for assessing cellular response to orthodontic force in vivo.
authors.affiliation: Department of Orthodontics, Yonsei University, Seoul, South Korea.
authors.forename: Kee-Joon
authors.initials: KJ
authors.lastname: Lee
authors.forename: Young-Chel
authors.initials: YC
authors.lastname: Park
authors.forename: Hyung-Seog
authors.initials: HS
authors.lastname: Yu
authors.forename: Seong-Ho
authors.initials: SH
authors.lastname: Choi
authors.forename: Yun-Jung
authors.initials: YJ
authors.lastname: Yoo
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001641:Bicuspid / Q000601:surgery; D003481:Cuspid / Q000503:physiopathology; D003722:Dental Alloys; D015232:Dinoprostone / Q000032:analysis* / Q000378:metabolism; D005246:Feedback; D005260:Female; D005500:Follow-Up Studies; D005883:Gingival Crevicular Fluid / Q000737:chemistry*; D006801:Humans; D007375:Interleukin-1 / Q000032:analysis* / Q000378:metabolism; D008297:Male; D009532:Nickel; D009969:Orthodontic Wires; D012690:Serial Extraction; D013314:Stress, Mechanical; D013997:Time Factors; D014025:Titanium; D014087:Tooth Movement Techniques / Q000295:instrumentation / Q000379:methods*; D015854:Up-Regulation
chemical_list: D003722:Dental Alloys; D007375:Interleukin-1; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium; D015232:Dinoprostone