Lin Bi-Chen, Zhao Yu-Ming, Yang Jie, Ge Li-Hong
Department of Pediatric Dentistry, Peking University School and Hospital of Stomatology, Beijing, China.
Eur J Oral Sci. 2012 Apr;120(2):147-52. doi: 10.1111/j.1600-0722.2012.00950.x.
Tooth agenesis is a common craniofacial congenital malformation in humans, but little is known about the mechanisms of root resorption in this condition. The purpose of this study was to investigate the mechanisms of root resorption in primary molars without successors. An animal model without permanent tooth germs was established by surgery in beagles. The times of onset of primary molar root resorption, with and without successors, were compared. The distribution of immune cells, odontoclasts, and their activating factors were determined by histochemistry and immunohistochemistry. Root resorption of primary mandibular molars without successors began later than physiological resorption. In primary molars without permanent germs, odontoclasts and immune cells were present mainly in the apical pulp at the start of root resorption, whereas in control teeth receptor activator of nuclear factor-κB ligand (RANKL)-positive cells were found mainly in the region of the periodontal ligament. CD14(+) and CD3(+) cells were found in both the pulp and the periodontal ligament region. These results suggest that the dental pulp of primary molars, as well as immune cells, may play an important role in root resorption in primary molars without permanent tooth germs.
牙齿发育不全是人类常见的颅面先天性畸形，但对于这种情况下牙根吸收的机制知之甚少。本研究的目的是探讨无继承恒牙的乳牙牙根吸收的机制。通过对比格犬进行手术建立了无恒牙胚的动物模型。比较了有和无继承恒牙的乳牙牙根吸收开始的时间。通过组织化学和免疫组织化学确定免疫细胞、破牙细胞及其激活因子的分布。无继承恒牙的下颌乳牙牙根吸收开始时间晚于生理性吸收。在无恒牙胚的乳牙中，牙根吸收开始时破牙细胞和免疫细胞主要存在于牙髓根尖部，而在对照牙中，核因子κB受体活化因子配体（RANKL）阳性细胞主要位于牙周膜区域。在牙髓和牙周膜区域均发现了CD14(+)和CD3(+)细胞。这些结果表明，乳牙牙髓以及免疫细胞可能在无恒牙胚乳牙的牙根吸收中起重要作用。
