Does human relaxin accelerate orthodontic tooth movement in rats?
Human relaxin was administered to young rats through either minipumps (group P) or subcutaneous injections (group I). Control rats received pump implants containing placebo (group C). Day 0 was the day of orthodontic appliance placement and activation to pull bilateral upper first molars forward, and day 14 was the end time point. Cephalometric radiographs (three repeated exposures) were taken at 0, 3, 5, 7, 10, and 14 days. The total length of three maxillary molar segments and the space between the first and second molars were measured under a dissecting microscope postmortem. Both groups P and I showed rapid tooth movement at day 3. Movement slowed, but it still increased gradually in group P while decreasing in group I after that. Concurrent tooth lateral drifts to the buccal side were smaller in both groups P and I. The length and space were larger in both groups P and I. Thus, administration of human relaxin may accelerate the early stages of orthodontic tooth movement in rats.
Liu
Zi Jun
ZJ
Department of Orthodontics, University of Washington, Seattle, WA 98195, USA. zjliu@u.washington.edu
King
Gregory J
GJ
Gu
Gao Man
GM
Shin
Ja Young
JY
Stewart
Dennis R
DR
D000818:Animals; D006801:Humans; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012065:Relaxin / Q000494:pharmacology*; D013997:Time Factors; D014087:Tooth Movement Techniques
D012065:Relaxin