| Objective:By studying the effects of two different orthodontic force,Matrix metalloproteinase-1(MMP-1),Matrix metalloproteinase-2(MMP-2),Matrix metalloproteinase-8(MMP-8),Matrix metalloproteinase-9(MMP-9),Tissue inhibitor of metalloproteinases-1(TIMP-1),and Tissue inhibitor of metalloproteinases-1(TIMP-1)in gingival crevicular fluid at different times and locations during the process of distal movement of canine.To explore the different expressions of MMPs and TIMPs on the pressure side and tension side of canine with time under different force values,and to analyze the possible role of the dynamic changes of MMPs and TIMPs in the process of orthodontic tooth movement.In order to summarize the optimal force of clinical canine and explore the distribution of MMPs and TIMPs in the process of orthodontic tooth movement,so as to provide an important reference index for the evaluation of clinical orthodontic periodontal tissue health at the molecular level.Method:Thirty patients who attended the orthodontic department of our hospital and required extraction of the first premolar in maxillary were randomly divided into 2 groups of 15 patients each,group A 100 g and group B 150 g.One maxillary canine was selected to apply different forces in the two groups.The other side of the canine was used as a blank control group with no force added.The proximal and distal gingival crevicular fluid was collected before T0 and after 1d(T1),7d(T2),14d(T3),21d(T4).Double-antibody sandwich enzyme-linked immunosorbent assay(ELISA)was used to detect the near and far mesial site concentrations of MMPs and TIMPs in the gingival crevicular fluid at different force values and at different times.The concentrations of MMPs and TIMPs in the gingival crevicular fluid at each time point were expressed by mean ± standard deviation((?)±s).The differences of MMP-1,MMP-2,MMP-8,MMP-9 and TIMP-1,TIMP-2 in gingival creval fluid at different positions of the two groups were analyzed over time,and the differences of MMPs and TIMPs at different positions over time between different force groups were analyzed,as well as the differences of tooth movement distance between different force groups.And the correlation between MMP-1,MMP-2,MMP-8,MMP-9 to TIMP-1 and TIMP-2 over time.P<0.05 was considered a statistically significant difference.Results:1.Within groups A and B,the concentration levels of MMP-1,MMP-2,MMP-8,MMP-9and TIMP-1 and TIMP-2 were statistically different in different locations over time,P<0.05.2.Distribution status of MMPs: In the proximal mid-side(tension zone)GCF,at T1,both sides of MMP-8 changed significantly(P<0.05);at T2,both sides of MMP-1 and MMP-2changed significantly(P<0.05);at T3,group A MMP-2 changed significantly(P<0.05),group B MMP-1,MMP-2 and MMP-9 changed significantly(P<0.05);at T4,both groups of MMP-1 and MMP-9 changed significantly(P<0.05).The peak concentrations in this side were mostly found in T1 and T2.In the distal side(pressure zone)GCF,both groups of MMP-1 and MMP-8 changed significantly at T1(P<0.05);at T2,MMP-1 and MMP-9changed significantly in group A and MMP-1 in group B(P<0.05);at T3,MMP-2 and MMP-9 changed significantly in both groups(P<0.05);at T4,MMP-9 changed significantly in both groups(P<0.05).The peak concentrations on this side were mostly found in T2 and T3.3.The distribution of TIMPs: At T1 in the GCF of the near proximal side(tension zone),there was no difference between the concentration levels of TIMP-1 and TIMP-2 in group A(P>0.05),and significant changes in TIMP-1 in group B(P<0.05);at T2,both groups had significant changes in TIMP-1(P<0.05);at T3,group A had significant changes in TIMP-2and group B had significant changes in TIMP-1(P<0.05);at T4,both groups had significant changes in TIMP-1 were significant(P<0.05).The peak concentrations in the proximal mid-side were mostly found in T2 and T3.In the distal mid-side(pressure zone)GCF,TIMP-1 changed significantly in T1,T2,T3 and T4 in both groups(P<0.05).The concentration peaks on the far mid-side appeared more at T2.4.Compard the 100 g group with 150 g group,there were differences in the changes in the levels of MMPs and TIMPs between the groups at all times except for T0(before force application)and TIMP-2 at mesial T2(application for 7 days)(P<0.05);there was no difference in the tooth movement distance between the groups(P>0.05).5.Correlation analysis: In group A,all types of MMPs and TIMPs were positively correlated at T0(P<0.05).There was no correlation between MMPs and TIMPs at T1(P>0.05).At T2,there was no correlation between MMP-9 with TIMP-1 and TIMP-2 (P>0.05),and the rest were positively correlated(P<0.05).At T3,MMP-1,MMP-8 and MMP-9 in pressure side were positively correlated with TIMP-1,and MMP-2 in pressure zone was positively correlated with TIMP-2(P<0.05),while the rest were not correlated(P>0.05).At T4,there was no correlation between MMP-1,MMP-8 and MMP-9 in pressure areas with TIMP-1(P>0.05),while the rest were positively correlated(P<0.05).In group B,MMPs and TIMPs were positively correlated at T0(P<0.05).At T1,MMP-1 and MMP-8with TIMP-1 in pressure region,MMP-1 with TIMP-2、MMP-8 with TIMP-2 and MMP-9with TIMP-2 in tension region,were positively correlated(P<0.05),and the rest were not correlated(P>0.05).At T2,there was no correlation between MMP-8 with TIMP-1 and TIMP-2(P>0.05),and the rest were positively correlated(P<0.05).In T3,there was no correlation between MMP-2 with TIMP-2(P>0.05),and the rest were positively correlated(P<0.05).At T4,there was no correlation between MMP-1 and MMP-8 with TIMP-1 and TIMP-2 in the tension zone(P>0.05),while the rest were positively correlated(P<0.05).Conclusions:1.In women,a force value of 100 g is more appropriate when moving the canine to a distal side,and the distance moved by the canine did not increase with the force value at higher level of force.2.Within the GCF during OTM,the change of MMP-8 in both near and far mesial side was significant at T1;at T2,the change of MMP-1 in both near and far mesial side was significant;at T3,the change of MMP-2 in both near and far mesial side was significant;at T4,the change of MMP-9 in both near and far mesial side was significant.3.The changes of TIMP-1 within the GCF during OTM were significant in both tension and pressure sides,which is a more sensitive biochemical index in periodontal tissue remodeling studies.4.Correlation analysis between MMPs and TIMPs can be used as a judgment indicator of periodontal tissue remodeling. |
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