| With the improvement of living standards, oral health literacy and pursuit of beauty, people have a more understanding of the malocclusion. The number of patients who turn to orthodontics for better aesthetics and function increase. However, Patients'pronunciation, chewing and appearance are affected by different degrees during orthodontic treatment. Orthodontic treatment is the process that alveolar bone is absorbed and regenerated, and then teeth are re-arranged. Better and faster correction of dentofacial deformities become the universal demand of patients. However, the lengthy course of orthodontic treatment is still a problem that orthodontists must face. How to accelerate orthodontic tooth movement and shorten the course of orthodontic treatment is one of the hot topics that many scholars have been studied for a long time. Prostaglandin, cyclic adenosine monophosphate, Parathyroid Hormone have been demonstrated to promote the formation of osteoclasts, and enhance the absorption of bone remodeling, thus accelerating orthodontic tooth movement. However, the high price for long-term use, side effects and unclear function make it difficult to use in clinic. Laser, magnetic, ultrasonic and other physical methods have been demonstrated to accelerate orthodontic tooth movement. But long-term effects of instability limited its clinical application. The traditional Chinese medicine is extensive and profound. Dipsacus asperoides which is common in TCM prescriptions for fracture can promote healing of bone fractures and strengthen kidney function. Fracture healing is the process of bone reconstruction, which is the same as alveolar change in orthodontic treatment. According to above theory, our experiment has selected classic traditional Chinese medicine Dipsacus asperoides with "psoralea corylifolia strong kidney" efficacy. Based on traditional Chinese medical theory and methods as well as modern research methods, we have designed the experiment to research the effect of Dipsacus asperoides on periodontal tissue remodeling of orthodontic tooth movement in rats.Objective:To observe the effects of feeding Dipsacus asperoides decoction on distance of tooth movement, periodontal tissue and bone density, the animal model for orthodontic tooth movement was established. The mechanism of Dipsacus asperoides in reconstruction of periodontium during orthodontic tooth movement was researched for developing traditional Chinese medicine. It will provide a theoretical basis for clinical application of Dipsacus asperoides and fill the gap in the field of orthodontics.Methods:48 female,6-week-old SPF healthy Wistar rats, weighing 190±10g, were selected and randomly divided into two groups, experimental group and control group, with each group 24 a week later adaptive feeding. The experimental group rats were fed 6g/kg dipsacus asperoides decoction everyday and the control group rats were fed 1.5ml normal saline everyday. Orthodontic coil spring was ligatured between the maxillary first molar and the two central incisors eight weeks after fed, then the animal model for tooth movement was established. The experimental group rats were fed 6g/kg dipsacus asperoides decoction everyday and the control group rats were fed 1.5ml normal saline everyday. The orthodontic coil spring were enhanced one time every 7 days. Two groups of rats were executed in batches on days 7,14,21,28. The maxillary molars and periodontium specimens were peeled off to measure the distances of the tooth movement and the density of alveolar bone. The periodontal tissue section were made and observed under the optics microscope. All the data were dealed with the PASM statistics 18 system, with the analysis of variance and t-test. Considering P<0.05 as difference has its statistical meaning. Results:1. The movement distance of the first molar to the middleAfter the t-test and variance analysis the average movement distance of the first molar between the experimental group and the control group had no statistical meaning after applying orthodontic stress 7 days (.P>0.05). Significant differences of the first molar movement distances were found between the experimental group and the control group after applying orthodontic stress 14,21,28d respectively (P<0.05).2. Changes in periodontal tissuePeriodontal capillaries were significantly expanded and large quantities of osteoclasts appeared in the pressure side of alveolar bone of experimental group. There were a large number of new bone deposited, osteoblasts dense distributed and new-born capillaries appeared in the tension side. The periodontal capillaries changed in the control group's, but the numbers of the osteoclasts were comparatively less than the experimental group's. The tension side had some new bone deposition and the osteoblasts distribution, the new-born capillaries appeared opposite less.The numbers of the osteoclasts of experimental group were all more than the control group's after applying orthodontic stress 7,14,21,28d. The difference had its statistical meaning (P<0.05). With the increase of time, the osteoclasts number of two groups increased gradually, and got its peak on the 21st day (P<0.05). But after the 21 st day, the number of the control group decreased while the experimental changed gently and remained a high level.3. Bone densityOn the 7th day of the experiment, the experimental group's bone density was slightly higher than the control group's, but the difference had no statistical meaning (P>0.05). But on days 14,21,28 bone density of the experimental group was obviously higher than the control group, and the difference had its statistical meaning (P<0.05). With the experiment progress carrying on, the bone density of two groups became lower gradually (P<0.05). But the bone density of the control group decreased obviously faster than the experimental group. The bone density of the experimental group decreased comparatively gentle.Conclusion:Dipsacus asperoides decoction can obviously accelerate the speed of orthodontic tooth movement in rats, significantly increase the number of osteoclasts in the pressure side of periodontal tissue and slow down the reduction of the bone density. |
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