Lin Bi-chen, Yang Jie, Zhao Yu-ming, Ge Li-hong
Department of Pediatric Dentistry, Peking University School, Beijing, China.
Zhonghua Kou Qiang Yi Xue Za Zhi. 2011 Mar;46(3):157-61.
To investigate the role of pulp in the root resorption of primary teeth without permanent tooth germs.
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.
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. Semi-quantification 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.
The pulp of primary tooth played an important role in the root resorption of primary tooth without permanent tooth germ.
探讨牙髓在无恒牙胚乳牙牙根吸收中的作用。
通过手术在比格犬建立无恒牙胚动物模型。定期拍摄根尖片观察牙根吸收情况。收集不同吸收阶段的下颌骨和牙髓样本。采用组织学染色和半定量逆转录聚合酶链反应（RT-PCR）分析破牙细胞及激活因子的分布。通过早期牙髓摘除术检测牙髓在无恒牙胚乳牙牙根吸收中的作用。
在无恒牙胚乳磨牙牙根吸收过程中，根管牙髓表面出现大量破牙细胞。半定量RT-PCR显示，在牙根吸收不同时期，无恒牙胚恒牙和乳牙牙髓中核因子κB受体活化因子配体（RANKL）mRNA与β-肌动蛋白表达量之比分别为0.1314、0.1901、0.2111和0.6058（P>0.05）。试验组无恒牙胚乳牙牙根吸收比对照组晚约5周。
乳牙牙髓在无恒牙胚乳牙牙根吸收中起重要作用。
