缺失恒牙胚的乳牙牙髓在牙根吸收中作用的实验观察  

The role of pulp in the root resorption of primary teeth without permanent tooth germs

作　　者：林碧琛[1] 杨杰[1] 赵玉鸣[1] 葛立宏[1] 

机构地区：[1]北京大学口腔医学院·口腔医院儿童口腔科,北京100081

出　　处：《中华口腔医学杂志》2011年第3期157-161,共5页Chinese Journal of Stomatology

基　　金：国家自然科学基金（30672321）;教育部博士点基金（20070001729）

摘　　要：目的 研究恒牙胚缺失情况下,乳牙牙髓在其牙根吸收中的作用.方法 通过手术方式建立恒牙胚缺失犬动物模型,定期拍摄X线片观察乳牙根吸收情况.获取乳牙牙根吸收各期颌骨及牙髓样本,采用组织学方法和半定量反转录聚合酶链反应（RT-PCR）分析破牙细胞及其活化因子的分布情况.通过早期乳牙牙髓摘除术验证乳牙牙髓在牙根吸收中的作用.结果 组织学研究结果显示,恒牙胚缺失情况下乳磨牙牙根吸收时,破牙细胞主要在牙根的髓腔侧聚集.半定量RT-PCR结果显示,恒牙牙髓、乳牙牙髓、恒牙胚缺失乳磨牙牙根吸收中、晚期牙髓中NF-κB受体激活蛋白配体mRNA与β-肌动蛋白的灰度值比值分别为0.1314、0.1901、0.2111、0.6058（P＞0.05）.早期乳牙牙髓摘除术后,恒牙胚缺失乳牙牙根吸收平均开始于第26周,晚于对照牙（第21周）.结论 在恒牙胚缺失乳牙牙根吸收过程中,乳牙牙髓发挥了重要作用.Objective To investigate the role of pulp in the root resorption of primary teeth without permanent tooth germs. Methods The animal model without permanent tooth germs was established by surgery in Beagle dog. The root resorption was observed by taking periapical radiographs periodically. The samples of mandibular bone and pulp at different resorption stages were collected. The distribution of odontoclasts and the activating factor was analyzed by histological staining and semiquantitative reverse transcriptase polymerase chain reaction（RT-PCR）. The role of pulp in the root resorption of primary teeth was tested by early pulpectomy. Results In the root resorption of primary molars without permanent teeth germs, a large number of odontoclasts were present on the pulpal surface of the root canal. Semiquantification RT-PCR showed that the ratios of the expression of receptor activator of NF-κB ligand （RANKL） mRNA and β-actin in the pulp of permanent teeth and primary teeth without permanent teeth germ during different periods of root resorption are 0. 1314, 0. 1901, 0. 2111 and 0. 6058 （ P 〉 0. 05 ）. The root resorption of primary teeth without permanent teeth germs in test groups was about 5 weeks later than that of control group. Conclusions The pulp of primary tooth played an important role in the root resorption of primary tooth without permanent tooth germ.

关 键 词：牙髓 牙根吸收 恒牙胚缺失乳牙 

分 类 号：R783.5[医药卫生—口腔医学]