Abstract:

To detect expression of MMPs in the gingival crevicular fluid of rats during tooth movement. MethodsOrthodontic appliances were fixed onto the maxilla of 20 6weekold female Wistar rats. The maxillary first molar in the experimental side was drawn medially by applying an excess force of 50?g, with both of the maxillary central incisors as anchorage. In the control side, the maxillary first molar was wound around the dental cervix with ligature wire. The gingival crevicular fluid of the rats was collected every week, and MMP1 and MMP9 were assayed in quantitation by using the biochemical techniques of SDSPAGE, Western blot and the Gel Doc quantitative analysis system. ResultsThe contents of MMP1 and MMP  9 in the gingival crevicular fluid increased at the 1st week in both sides, and greatly increased at the 2nd week. It reached a peak at the 3rd week, and fell back from the 4th week. At the 7th week, the contents were the least but more than that before the appliances were fixed. There was statistical significance in the contents of MMP1 between the experimental side and the control side at the respective weeks(P＜0.05), and the experimental side was more than the control side. But no statistical significance was shown in the content of MMP9 between the two sides(P＞0.05). ConclusionsMMP1 and MMP9 in the gingival crevicular fluid play some role in orthodontic tooth movement. MMP1 may be more closely connected with tooth movement than MMP9.

Key words:  Orthodontics; Tooth movement; Matrix metalloproteinases;  Gingival crevicular fluid;  Rats