恒磨牙窝沟釉质表面结构扫描电镜观察

目的观察未萌牙、初萌牙、成年牙咬合面窝沟和光滑面釉质表面的超微结构，比较窝沟釉质表面在萌出前后不同时期的变化。方法用激光龋齿检测仪和显微放射照相法确定咬合面窝沟无龋损的未萌牙6颗、初萌牙7颗、成年牙5颗为研究样本。劈开窝沟，对其窝沟釉质壁的表面及颊面釉质进行扫描电镜观察。结果①未萌牙窝沟侧壁釉质表面可见明显的釉质横纹，釉柱末端凹陷明显并分布有大量的微孔和灶性孔，类似蜂窝状，与颊面釉质表面无明显差别。②初萌牙窝沟侧壁釉质表面表现与未萌牙基本一致，颊面微孔减少。③成年牙窝沟侧壁上部釉质表面可见明显的表浅凹陷，可见少量的微孔，表面较光滑，较致密；窝沟下部的釉质表面结构较疏松，存在较多的微孔和灶性孔，呈蜂窝状结构，与未萌牙相似。结论在未萌牙、初萌牙、成年牙窝沟侧壁下部存在多孔状釉质发育缺陷。成年牙窝沟上部的釉质表面结构接近其颊面，与窝沟底部相比有较大差别，提示窝沟上部釉质在牙萌出后出现修复现象。

Observation of the surface structure of enamel in pits and fissures of permanent molars

Objective To observe the structures of enamel surface in pits and fissures of unerupted, young and mature permanent molars. Method Six unerupted,7 young and 5 mature permanent molars without caries were enrolled in this study. The fissures in the occlusal surface were split along the fissures to expose the fissure enamel surfaces which were then observed by scanning electron microscope. Results There was an obvious enamel perikymata in the fissure enamel surface paralleling with the long axis of the unerupted permanent molars and lots of micro - hole were observed in the process of the enamel perikymata which made the enamel surface roughly looked like honeycomb. Similar structures were found in the fissure enamel surface of young permanent molars. In mature permanent molars, lots of pits of prism ends and little amount of micro - hole were seen in enamel surface of the upper parts of the fissure. The fissure bottom of mature permanent molars had a similar enamel surface structure to that of the unerupted and young permanent molars. Conclusion There were many developmental defects in the pits and fissure enamel. The fissure entrance enamel of mature permanent molars was similar to its buccal surface and different from its fissure bottom enamel. This suggests that there was a remineralization on the fissure entrance enamel surface of permanent molars.