Detection Of DSP, DSPP In Gingival Crevicular Fluid Of Rat During Root Resorption Following Experimental Tooth Movement And Relationship With The Extent Of Root Resorption

Object:The purpose of this study was to establish the model of root resorption following experimental tooth movement in rats, to observe the expression of DSPP and DSP in GCF after experimental tooth movement. To find the relationship between the expression with the root resorption by compairing the different expressions in length wise. To achieve the early diagnosis and monitor the begning and developing of root resorption in clinic.Methods:72 Wistar rats were used in experiment. The animals were divided into 3 groups on average: A control group, B light force group (40g force) and C heavy force group (100g force). An orthodontic appliance, consisting of a Ni-Ti spring connected the first molar of upper right side and the two upper incisors by 0.20mm ligature wire was used in this study. The experimental tooth was drawn to mesial direction by applying a force of 40g in B group and a force of 100g in C group, with both of the maxillary central incisors as anchorage. The GCF of rats was collected at the 1st,3rd,5th,7th,10th,14th,21st,28th day. And the expression of DSP and DSPP was assayed with the biochemistry techniques of SDS-PAGE and Western blot. The histological slices were made, including a part of upper jaw, the experimental tooth and periodontal tissue related. Sections(5μm thick) were stained with hematoxylin and eosin(H&E), and Tartrate resistant acid phosphatase (TRAP) to observed the root resorption.Results:1. Treated by 40g mesial force, the upper right first molar moved obviously in the mesial and palatal direction in the light force group. The experimental tooth moved not so distinctly in the heavy force group. And the mount of tooth moving became bigger with the going on.2. The direct alveolar resorption could be observed after 3d treated by light and heavy force, while the root resorption could'nt. The cement resorption could be observed after treated by heavy force for 5 days. And the dentin resorption could be observed after 7d treated by heavy force. The direct alveolar resorption could be observed after 10d,14d,21d treated by light and heavy force, while the root resorption could'nt. The result of 28d group is almost the same with the control group.3. By detecting the expression of DSP and DSPP of the three groups treated by the force for 1, 3, 5, 7, 10, 14, 21and 28 days, we found that the expression of DSP and DSPP started to grow stronger in the GCF of the rats treated by heavy force for 5 days; the expression of DSP and DSPP was the most strong in the GCF of the rats treated by heavy force for 7 days; the expression of DSPP became weaker gradually in the GCF of the rats treated by force for 10, 14, 28 days, and there was no expression of DSP. By comparing the differences of the expression of DSP and DSPP of the three groups, we found that the expression of DSP and DSPP of the experiment groups was obviously stronger than that of the control group, and the expression between the light and heavy force group was also obviously(P <0.05).Conclusion:1. After building the orthodontic movement model with the upper center incisors as anchorage teeth and the upper first molar as moving tooth, the upper first molar rotated toward to palatal direction. The reason may be that the center incisors was closer to the midline than the first molar and the center incisors could be tolerant the palatal force. So we should improve the model to avoid the root resorption caused by occolusion factors.2. After observing the essays of the histological tissue and the tissue slices of tooth and odontoperiosteum, we found that the proper force and the lasting time of the force could lead to the rapid tooth moving without significant root resorption. So the doctors must use the proper orthodontic force and control the lasting time of the force in clinics.3. By comparing the expression of DSP and DSPP in the GCF of the three groups rats treated by the force for different days (1, 3, 5, 7, 10, 14, 21, 28 days), we found that there was the expression of DSP in the group treated by heavy force for 5 days which implied root resorption, and we could use DSP and DSPP as biological parameters to diagnose root resorption in the early stage; we found that the expression of DSP and DSPP was the most strong in the group treated by heavy force for 7 days and the intension of the expression became stronger with the root resorption developed, while the intension became weaker with the time going on. All of the results above implied that DSP and DSPP played some roles in the beginning and developing of root resorption, and they could be used to detect the extent of root resorption. The experiment provided theory evidence for monitoring the development of root resorption with biological method in clinics.