咬合力对小鼠磨牙牙根发育影响的初步研究
发布时间：2018-08-13 10:01
【摘要】：目的:本研究通过建立咬合力不对称动物模型,探讨咬合力大小在牙根发育中的作用,并且进一步初步尝试从分子水平探讨影响牙根发育的机制,为牙根再生提供发育阶段的研究基础,并在降低口腔治疗风险的同时为正畸治疗提供更为广泛的适应症。方法:选取野生型C57BL/6J近交系小鼠出生后第7.5、14.5、15.5、21.5、28.5、35.5、42.5、49.5、56.5、63.5、70.5、77.5、84.5(PN7.5、14.5、15.5、21.5、28.5、35.5、42.5、49.5、56.5、63.5、70.5、77.5、84.5)日龄第一磨牙作为实验观察对象,大体观察咬合关系及下颌第一磨牙牙根长度变化。再选取PN15.5野生型C57BL/6J近交系小鼠,1%戊巴比妥钠(3mg/100g)腹腔麻醉,采用拔除上颌牙的方法建立咬合力不对称的下颌磨牙模型,分别在术后6天、10天、25天、75天(即PN21.5、25.5、40.5、90.5日龄)处死动物;同时取正常生长条件下PN21.5、PN25.5、PN40.5、PN90.5日龄为对照组,取小鼠下颌第一磨牙为研究对象。4%多聚甲醛固定,EDTA脱钙,参照常规步骤进行石蜡切片和苏木精-伊红(Hematoxylin-Eosin,H.E.)染色、PCNA和Shh抗体进行免疫组织化学染色,以及TRAP染色。结果:1.本研究通过对C57BL/6J野生型小鼠上下颌第一磨牙咬合关系及牙根长度的连续观察发现,在PN15.5天时,突破口腔黏膜暴露于口腔中,开始牙合向移动,因此选择PN15.5天的小鼠为研究对象通过拔除上颌第一磨牙的方法建立了咬合力不对称的动物模型,用于研究咬合力对于牙根发育的影响。2.C57BL/6J近交系小鼠磨牙正常发育过程中,随生长发育小鼠下颌第一磨牙的长度逐渐增加,但具有一定的限度;牙根的长度也随时间逐渐增加,其生长速度先快后慢,在生长发育的后期牙根长度增加以代偿牙尖磨耗维持牙齿的长度;根尖部牙周膜厚度及HERS细胞的数目会随着生长发育逐渐减少,牙齿发育趋于成熟;根部牙骨质逐渐增多,牙根逐渐粗壮,以适应牙齿的功能。3.咬合力作为一个外界因素对牙根的发育具有一定的影响,无咬合力作用时:牙根狭长、HERS细胞数目较多、根尖部牙周膜较宽,同时根部牙本质形成较多,根尖部细胞增殖活跃,TRAP染色阳性细胞较多;咬合力增强时,牙根短粗、HERS细胞数目减少、根尖部牙周膜较窄、根部牙本质形成较少,TRAP染色阳性细胞较少。4.在牙根发育过程中,咬合力减弱导致牙根狭长,是HERS及根尖周围细胞增殖、根尖底部牙槽骨吸收的结果,同时较宽的牙周间隙可为牙根的延长提供空间。咬合力大小可能影响Shh的表达,进而影响牙根的长度,其具体机制需进一步研究。结论:通过对小鼠磨牙的研究发现,咬合力作为一个外界因素在牙根发育过程中起重要作用。咬合力的改变会影响牙根的长度宽度、牙周膜的宽度及HERS细胞数目;而造成这一现象的原因可能与HERS及根尖周围细胞增殖、根尖底部牙槽骨吸收相关。同时,发现根尖部Shh的表达受咬合力大小的影响,进而影响牙根的长度。
[Abstract]:Objective: to explore the role of bite force in root development by establishing an asymmetric animal model of bite force, and to explore the mechanism of tooth root development at molecular level. To provide the basis for the development of root regeneration, and to reduce the risk of oral treatment and provide a broader indication for orthodontic treatment. Methods: the first molar of the wild-type C57BL/6J inbred strain mice was selected as the experimental object. The first molar of the first molar was selected as the experimental object. The first molar of the wild type C57BL/6J was 7.514.515.515.55.28.514.515.515.515.55.49.56.577.584.5) of the first molar at the age of 28.514.514.515.515.55.52.55.49.56.5. 77.584.5) and the relationship between occlusion and the length of mandibular first molars was observed in a general way. The experimental results showed that the first molar of the wild type of C57BL/6J inbred strain was 77.54.5% and that of the first molar was 77.54.5.The relationship of occlusion and the change of the root length of the first mandibular molars were observed. After intraperitoneal anesthesia with 1% pentobarbital sodium (3mg/100g) in PN15.5 wild-type C57BL/6J inbred strain mice, the mandibular molar model with asymmetric bite force was established by extraction of maxillary teeth. The animals were killed on the 6th day, 10th day, 25 days and 75 days, respectively. At the same time, the normal growth conditions of PN21.5 PN25.5PN40.5 and PN90.5 were taken as the control group. The first mandibular molars of mice were taken as the study object. The EDTA was fixed with 4% paraformaldehyde. The paraffin sections and Hematoxylin-Eosin H.E. were carried out according to the routine procedure. PCNA and Shh antibodies were stained by immunohistochemistry and TRAP staining. The result is 1: 1. In this study, we observed the occlusal relationship and root length of the first molar of C57BL/6J wild type mice. It was found that during the PN15.5 day, the oral mucosa was exposed to the oral cavity and the occlusion began to move. Therefore, an animal model of asymmetric bite force was established by the extraction of maxillary first molar in mice on PN15.5 day, which was used to study the effect of bite force on root development. 2. C57BL / 6J inbred mouse molars developed normally. The length of the mandibular first molar increased gradually with the growth of the mouse, but there was a certain limitation, and the length of the root increased with time, and the growth rate of the first molar increased first and then slowly. At the later stage of growth and development, the root length was increased to replace the attrition of the tip, the thickness of periodontal ligament and the number of HERS cells in the apical region decreased gradually, and the tooth development tended to mature, and the root cementum gradually increased. The root of the tooth grew thicker to fit the function of the tooth. As an external factor, occlusal force has a certain effect on the development of the root. When no bite force is used, the number of HERS cells in the root is more, the periodontal ligament in the apical region is wider, and the root dentin is more formed. The number of HERS cells decreased, the periodontal ligament was narrower, and the formation of root dentin was less, but the positive cells of trap staining were less. 4 when the bite force was enhanced, the number of HERS cells in the root tip was decreased, the periodontal ligament in the apical region was narrower, and the positive cells of trap staining in the root dentin were less than those in the root. In the process of root development, the reduction of bite force leads to the narrow and narrow root, which is the result of the proliferation of HERS and periapical cells, the resorption of alveolar bone at the base of the root tip, and the wide periodontal space can provide space for the extension of the root. The size of occlusal force may affect the expression of Shh and the length of root. Conclusion: as an external factor, bite force plays an important role in the root development of mouse molars. The change of occlusal force may affect the width of root length, the width of periodontal ligament and the number of HERS cells, which may be related to the proliferation of HERS and periapical cells and the resorption of alveolar bone at the root base. At the same time, it was found that the expression of Shh in the apical region was affected by the bite force and the root length.
【学位授予单位】：首都医科大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R783.5
本文编号：2180647
[Abstract]:Objective: to explore the role of bite force in root development by establishing an asymmetric animal model of bite force, and to explore the mechanism of tooth root development at molecular level. To provide the basis for the development of root regeneration, and to reduce the risk of oral treatment and provide a broader indication for orthodontic treatment. Methods: the first molar of the wild-type C57BL/6J inbred strain mice was selected as the experimental object. The first molar of the first molar was selected as the experimental object. The first molar of the wild type C57BL/6J was 7.514.515.515.55.28.514.515.515.515.55.49.56.577.584.5) of the first molar at the age of 28.514.514.515.515.55.52.55.49.56.5. 77.584.5) and the relationship between occlusion and the length of mandibular first molars was observed in a general way. The experimental results showed that the first molar of the wild type of C57BL/6J inbred strain was 77.54.5% and that of the first molar was 77.54.5.The relationship of occlusion and the change of the root length of the first mandibular molars were observed. After intraperitoneal anesthesia with 1% pentobarbital sodium (3mg/100g) in PN15.5 wild-type C57BL/6J inbred strain mice, the mandibular molar model with asymmetric bite force was established by extraction of maxillary teeth. The animals were killed on the 6th day, 10th day, 25 days and 75 days, respectively. At the same time, the normal growth conditions of PN21.5 PN25.5PN40.5 and PN90.5 were taken as the control group. The first mandibular molars of mice were taken as the study object. The EDTA was fixed with 4% paraformaldehyde. The paraffin sections and Hematoxylin-Eosin H.E. were carried out according to the routine procedure. PCNA and Shh antibodies were stained by immunohistochemistry and TRAP staining. The result is 1: 1. In this study, we observed the occlusal relationship and root length of the first molar of C57BL/6J wild type mice. It was found that during the PN15.5 day, the oral mucosa was exposed to the oral cavity and the occlusion began to move. Therefore, an animal model of asymmetric bite force was established by the extraction of maxillary first molar in mice on PN15.5 day, which was used to study the effect of bite force on root development. 2. C57BL / 6J inbred mouse molars developed normally. The length of the mandibular first molar increased gradually with the growth of the mouse, but there was a certain limitation, and the length of the root increased with time, and the growth rate of the first molar increased first and then slowly. At the later stage of growth and development, the root length was increased to replace the attrition of the tip, the thickness of periodontal ligament and the number of HERS cells in the apical region decreased gradually, and the tooth development tended to mature, and the root cementum gradually increased. The root of the tooth grew thicker to fit the function of the tooth. As an external factor, occlusal force has a certain effect on the development of the root. When no bite force is used, the number of HERS cells in the root is more, the periodontal ligament in the apical region is wider, and the root dentin is more formed. The number of HERS cells decreased, the periodontal ligament was narrower, and the formation of root dentin was less, but the positive cells of trap staining were less. 4 when the bite force was enhanced, the number of HERS cells in the root tip was decreased, the periodontal ligament in the apical region was narrower, and the positive cells of trap staining in the root dentin were less than those in the root. In the process of root development, the reduction of bite force leads to the narrow and narrow root, which is the result of the proliferation of HERS and periapical cells, the resorption of alveolar bone at the base of the root tip, and the wide periodontal space can provide space for the extension of the root. The size of occlusal force may affect the expression of Shh and the length of root. Conclusion: as an external factor, bite force plays an important role in the root development of mouse molars. The change of occlusal force may affect the width of root length, the width of periodontal ligament and the number of HERS cells, which may be related to the proliferation of HERS and periapical cells and the resorption of alveolar bone at the root base. At the same time, it was found that the expression of Shh in the apical region was affected by the bite force and the root length.
【学位授予单位】：首都医科大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R783.5
【参考文献】
相关期刊论文 前2条
1 Xiao-Feng Huang;Yang Chai;;Molecular regulatory mechanism of tooth root development[J];International Journal of Oral Science;2012年04期
2 张瑞;黄晓峰;张方明;;核因子C(Nfic)与牙根发育[J];北京口腔医学;2011年06期
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