Aoki H
Shikwa Gakuho. 1989 Oct;89(10):1605-37.
Single subcutaneous injections of sodium fluoride (84 mg/kg NaF) were administered to male Wistar rats weighing 100 g each. After 6, 12, and 24 hours and then after 2 and 5 days, the animals were fixed by perfusion with a mixture of 2.5% glutaraldehyde and 2.0% paraformaldehyde; and their upper incisors were subjected to optical microscopy, microradiography, and electron microscopy. 1. Changes in ameloblasts in the matrix-formation stage: Large vacuoles and dark globules, which frequently appeared to be stacked within the cell, could be seen in the distal one-third of the ameloblast 6 hours after NaF injection. These globules and vacuoles disappeared 24 hours after injection. Distortion of the Tomes' processes and separation of the ameloblasts from the enamel surface too could be seen. The separated areas gradually expanded to form cystic cavities, which developed toward the end of the formation stage of amelogenesis. But these cavities never extended to ameloblasts in the transitional stage. 2. Changes in ameloblasts in the transitional stage: Transitional ameloblasts may be divided into 2 stages: the early transitional stage, during which the proximal portion of the Tomes' process persists, and the late transitional stage, during which all trace of the Tomes' process has disappeared and a basement membrane-like structure has been produced. The appearances of ameloblasts in these two stages altered after NaF injection. In the early transitional stage, 6 hours after the injection, large vacuoles and dark globules appeared in the distal portion of the cell. Similar to vacuoles appearing during the matrix-formation stage, these vacuoles and globules disappeared 24 hours after injection. Traces of the Tomes' process, however, persisted and assumed an irregular, wavy form. The adjacent enamel adapted to and interdigitated with the cel surfaces without a structure resembling the basement membrane. NaF injection caused slight changes in the late transitional stage: small vacuoles appeared at the distal ends of the cell and disappeared 24 hours later. 3. Changes in the ameloblasts in the enamel-maturation stage: Six hours after the injection, small vacuoles appeared at the distal portion of the cell close to the striated border which was poorly developed. These vacuoles disappeared, and the striated border resumed its usual features 24 hours after the injection. 4. Changes in the enamel: In the forming enamel, a calciotraumatic line consisting of hypermineralized and hypomineralized layers could be seen. Another hypermineralized line appeared at the enamel surface adjacent to the transitional stage. Electron microscopy showed that this hypermineralized layer consisted of crowded, disoriented, needle-shaped crystals.
对体重为100克的雄性Wistar大鼠进行皮下单次注射氟化钠（84毫克/千克氟化钠）。在6、12和24小时后，然后在2天和5天后，通过灌注2.5%戊二醛和2.0%多聚甲醛的混合物对动物进行固定；并对其上颌切牙进行光学显微镜、显微放射摄影和电子显微镜检查。1. 成釉细胞在基质形成阶段的变化：氟化钠注射6小时后，在成釉细胞远侧三分之一处可见大空泡和暗球，这些暗球似乎经常堆叠在细胞内。这些球和空泡在注射后24小时消失。还可见托姆斯突的扭曲以及成釉细胞与釉质表面的分离。分离区域逐渐扩大形成囊腔，在釉质形成阶段末期发展。但这些腔从未延伸到过渡阶段的成釉细胞。2. 成釉细胞在过渡阶段的变化：过渡性成釉细胞可分为两个阶段：早期过渡阶段，此时托姆斯突的近端持续存在；晚期过渡阶段，此时托姆斯突的所有痕迹消失并产生类似基底膜的结构。氟化钠注射后这两个阶段的成釉细胞外观发生改变。在注射后6小时的早期过渡阶段，细胞远侧部分出现大空泡和暗球。与基质形成阶段出现的空泡相似，这些空泡和暗球在注射后24小时消失。然而，托姆斯突的痕迹持续存在并呈现不规则的波浪状。相邻的釉质适应并与细胞表面相互交错，没有类似基底膜的结构。氟化钠注射在晚期过渡阶段引起轻微变化：细胞远端出现小空泡，24小时后消失。3. 成釉细胞在釉质成熟阶段的变化：注射后6小时，在靠近发育不良的纹状缘的细胞远侧部分出现小空泡。这些空泡消失，注射后24小时纹状缘恢复其正常特征。4. 釉质的变化：在正在形成的釉质中，可见由矿化过度层和矿化不足层组成的钙创伤线。在与过渡阶段相邻的釉质表面出现另一条矿化过度线。电子显微镜显示，这条矿化过度层由密集、无序的针状晶体组成。
