Study On The Role Of MMP-2 In Orthodontic Root Resorption

Objectives: This experiment aims establish the root resorption model caused by SD rat orthodontic force,we also observe the expression of matrix metalloproteinase-2(MMP-2)in healthy SD rats and root resorption in teeth,and discuss the role of MMP-2 in development of orthodontic root resorption.Methods: We selected 35 6-8 weeks old SD male rats,weighing 200 g ± 20 g or so.The first molar on the right side of the maxillary was selected as the experimental side,and the blank control group was the first molar of the maxillary right.An orthodontic traction device was applied between the right first molar and the maxillary incisor in the experimental rats,and the mesial tractive force of 60 g was applied.According to the random number table,we randomly divided into 7 groups: 1 days,3 days,5 days,7 days,14 days,21 days and blank control group,5 rats in each group.Rats were sacrificed at the set time and drawn.We use hematoxylin-eosin staining observe the root resorption,the expression of tension side and pressure side of experience group and matrix metalloproteinase-2(MMP-2)in periodontal tissue of control group were performed by immuneohisto chemistry and imaged use quantitative analysis.Using SPSS17.0 statistical software to process data.Result: The concentrations of MMP-2 was raised gradually,reached the peak at 7 d,and then gradually decline,21 d tends to be stable.Compared with the tension side and the pressure side,there was no significant difference between the control group and the 1d group?3dgroup(P>0.05).The difference between the tension side and the pressure side of the other groups was statistically significant(P<0.05).Conclusion: MMP-2 play an important role in development of orthodontic root resorption.