On the origin of intrinsic matrix of acellular extrinsic fiber cementum: Studies on growing cementum pearls of normal and bisphosphonate-affected guinea pig molars
On the origin of intrinsic matrix of acellular extrinsic fiber cementum: Studies on growing cementum pearls of normal and bisphosphonate-affected guinea pig molars
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DOI：
10.1034/j.1600-0447.2002.21239.x
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发表时间：
2002-06-01
影响因子：
1.9
通讯作者：
Takano, Y
中科院分区：
文献类型：
--
作者：
Jayawardena, CK;Takahashi, N;Takano, Y
牙骨质珍珠(Cementum珍珠，CPS)是豚鼠磨牙成熟牙釉质上形成的一种脱细胞外源性纤维牙骨质(AEFC)。本研究以正常豚鼠磨牙和双磷酸盐损伤的豚鼠磨牙为实验模型，探讨AEFC固有基质的形成过程。一组豚鼠连续给予1-羟乙叉-1，1-双磷酸盐(HEBP)2wk，以抑制生长中CPS的矿化。HEBP对釉质器官的开窗和牙周细胞在成熟牙釉质裸露表面的迁移似乎没有影响，而先前存在的CPS的从头形成和生长在相同的条件下没有进行。骨桥蛋白的免疫反应仅定位于预制的CPS的矿化基质上，这意味着受影响的CPS上没有额外的内在牙骨质基质的沉积或积聚，矿物相的传播被阻止了。在正常组和HEBP处理组，碱性磷酸酶在与CP形成部位密切相关的牙周膜细胞和沿CPS矿化前沿的细胞上出现明显的碱性磷酸酶反应。这些观察结果表明，矿化过程本身在AEFC基质的沉积中起着核心作用，而牙周细胞通过釉质器官进入成熟的釉质表面的碱性磷酸酶在CPS的矿化过程中起着关键作用。
Cementum pearls (CPs) belong to a type of acellular extrinsic fiber cementum (AEFC) that form on the maturing enamel of guinea pig molars. This study aimed to elucidate the forming process of intrinsic matrix of AEFC using the CPs of normal and bisphosphonate-affected guinea pig molars as experimental models. A group of guinea pigs were subjected to continuous administration of 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) for 2 wk to inhibit mineralization of growing CPs. Fenestration of the enamel organ and migration of periodontal cells on to the exposed surface of maturing enamel appeared to be unaffected by HEBP, whereas de novo formation as well as growth of pre-existing CPs did not proceed tinder the same conditions. Immunoreactions for osteopontin were located exclusively on the mineralized matrix of preformed CPs, implying the absence of additional deposition or accumulation of putative intrinsic cementum matrix on the affected CPs, where the propagation of mineral phase had been arrested. In both normal and HEBP-treated groups, distinct enzymatic reactions for alkaline phosphatase appeared on the cells of the periodontal ligament associated closely with the sites of CP formation, and along the mineralization front of CPs. These observations suggest that the mineralization process per se plays a central role in the deposition of AEFC matrix and that alkaline phosphatase of periodontal cells penetrating through the enamel organ to the maturing enamel surface plays a key role in the mineralization process of CPs.