| Objective: The purpose of this thesis is to establish the model of tooth movement following experimental osteoporosis of ovariectomized in rats, then measure the distances of orthodontic tooth movement, count the number of osteoclasts and odontoclasts, observe the different expression of DSP (dentin saloprotein) and DSPP (sialophosphoproteins) in GCF after experimental tooth movement in different durations, to research the characteristics of root resorption following tooth movement in osteoporosis rats.Methods: Select fifty 6-month-old female Wistar rats and averagely grouping them into 10 groups by body weight randomly. Consider 5 groups as ovariectomized control group (OVX), each rat in OVX group treated by force on teeth in different durations: 0days, 5 days, 7 days, 10 days, 14 days; and the other 5 groups considered as sham control group (Sham), each rat in Sham group also treated by force on teeth in different durations: 0days, 5 days, 7 days, 10 days, 14 days. The OVX group had an operation, not only remove the adipose tissue around the ovarian, but also included the ovarians; but each rat in sham shall be removed the adipose tissue around the ovarian only.After six months since operation, the first molar of rat were mesially moved with 0.49N force, consisting of a Ni-Ti coil spring connected the maxillary first molar and both of the upper medial incisor of each experimental rat, to build experimental model of orthodontic tooth movement.The rats'maxillary precise impressions were made both before and after experiment in 0, 5, 7, 10, 14 days by using some prefabricated special stock and alginate impression material, super-hard gesso perfusion. The distance of tooth movement was measured by stereomicroscope.The GCF of rats in different Sham and OVX were collected at 0, 5, 7, 10, 14 days. The expression of DSP and DSPP was assayed with the biochemistry techniques of Western blot.Cut take rat bilateral upper jaw specimens (include three molars and a part of upper jaw and related periodontal tissue), fixed in 4% buffered formalin, and decalcified with EDTA. They were embedded in paraffin. To observe the root resorption, sections were stained with hematoxylin and eosin (HE), tartrate resistant acid phosphatase (TRAP), and counted the number of osteoclasts and odontoclasts. Then the rats were executed and their left femur, tibia and lumbar samples would be collected at the same time. Latter, bone mineral densities of rats were measured with dual-energy X-ray absorption metry.All data using the statistical software SPSS 13.0, conduct independent t-test, set P < 0.05 have statistical significance.Results:1 Femur, tibia and lumbar bone mineral density (BMD) of ratsAfter six month of the operation of remove the ovaries, the femur, tibia and lumbar BMD of OVX groups were 0.19±0.01g/cm2, 0.14±0.01g/cm2, 0.17±0.01g/cm2; the femur, tibia and lumbar BMD of sham groups were 0.20±0.01g/cm2, 0.15±0.01g/cm2, 0.21±0.02g/cm2 (P < 0.05). Differences between the groups were statistically significant.2 Gross specimen observedSince adding the force on teeth for 5 days, the first upper molars of rats in OVX groups were mesially moved obviously, the upper first molar rotated toward to palatal direction and a little elongation to the jaw. Between the first and the second upper molars there was a distance visible. After add the force on teeth for 7 days, the first upper molars of rat in sham groups were mesially moved obviously, the upper first molar rotated toward to palatal direction and a little elongation to the jaw. Between the first and the second upper molars there was a distance visible, too.3 The distance of the first upper molars movementThe distance of tooth movement was measured by stereomicroscope. In the group of adding the force on teeth for 5 days, the OVX group's distance was 74.14±4.38μm, the Sham group's distance was 58.03±6.40μm; in 7 days, the OVX group's distance was 169.96±28.97μm, the Sham group's distance was 127.87±6.05μm; in 10 days, the OVX group's distance was 260.84±41.85μm, the Sham group's distance was 195.61±9.53μm; in 14 days, the OVX group's distance was 182.72±21.39μm, the Sham group's distance was 250.09±28.21μm; P<0.05, in the group of adding the force on teeth for the same days the differences between the groups of OVX and Sham was statistically significant.4 Histological studyThe osteoclasts, odontoclasts, alveolar resorption and root resorption could be seen in the sections were stained with HE in OVX groups in optical microscope. The osteoclasts, odontoclasts and alveolar resorption could be seen in the sections were stained with HE in Sham groups in optical microscope, the root resorption was deep within dentin layer. This trend strength prolonged, with became apparent. The osteoclasts activity significantly in every groups.The number of odontoclasts in the group of adding the force on teeth for 5 days, the OVX group's number was 1.50±1.58, the Sham group's number was 5.20±2.30; in 7 days, the OVX group's number was 1.90±2.56, the Sham group's number was 5.80±3.74; in 10 days, the OVX group's number was 3.40±2.59, the Sham group's number was 12.00±12.32; in 14 days, the OVX group's number was 2.40±1.26, the Sham group's number was 4.20±1.81; P<0.05, in the group of adding the force on teeth for the same days the differences between the groups of OVX and Sham was statistically significant.The number of osteoclasts in the group of adding the force on teeth for 5 days, the OVX group's number was 9.40±1.78, the Sham group's number was 2.20±1.40; in 7 days, the OVX group's number was 11.60±2.88, the Sham group's number was 4.50±2.12; in 10 days, the OVX group's number was 6.20±1.75, the Sham group's number was 4.50±1.78; in 14 days, the OVX group's number was 4.50±1.78, the Sham group's number was 2.30± 1.95; P<0.05, in the group of adding the force on teeth for the same days the differences between the groups of OVX and Sham was statistically significant.5 Western blotBy detecting the expression of DSPP and DSP in the 10 groups, we found that the expression of DSPP and DSP in the OVX groups added force after 7～14 days, the 5th day group was expression DSPP only. But the expression of DSPP and DSP in the Sham groups in 7～14 days groups.By using the image analysis software of BandScan V5.0, the number in the group of adding the force on teeth for 5 days, the OVX group's number was 118.60±7.89, the Sham group's number was 156.60±16.46; in 7 days, the OVX group's number was 132.00±9.57, the Sham group's number was 177.80±13.55; in 10 days, the OVX group's number was 118.60±16.33, the Sham group's number was 178.00±9.97; in 14 days, the OVX group's number was 113.60±14.94, the Sham group's number was 169.80±13.81; P<0.05, in the group of adding the force on teeth for the same days the differences between the groups of OVX and Sham was statistically significant.Conclusions:1 The speed of the first upper molars movement in OVX groups was faster than the Sham groups both under force 0.49N lasted for 14 days.2 With the equal force and same duration, the root resorption of OVX groups was lighter than the Sham groups. |
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