Smith C E
Am J Anat. 1975 Apr;142(4):431-55. doi: 10.1002/aja.1001420403.
The epithelial tissue forming the posterior aspect of the apical foramen in the upper incisor of the rat was reconstructed from 1 mum thick serial cross sections. Like the lower incisor, this portion of the odontogenic organ in the upper incisor was composed of a bulbous and a "U"-shaped part. However, the bulbous part was considerably blunter and the "U"-shaped part much larger in circumference in comparison to the lower incisor. Although no differences were found between the upper and lower incisor regarding the contents and the basic organization of cells within each part of the odontogenic organ, specific differences were found within the bulbous part in the upper incisor. There was a more definitive boundary between the outer dental epithelium and stellate reticulum, a more intimate relationship of cell streams to the stellate reticulum, and a noticeable lack of swirling of cells as part of the streams. These features suggest that the activity inside the bulbous part is less intense in the upper incisor than it is in the lower incisor. In addition, the relationships between the bulbous part, the "U"-shaped part and the root sheath part of the odontogenic organ and the enamel organ were described for the upper incisor.
通过1微米厚的连续横断面重建了大鼠上颌切牙根尖孔后方的上皮组织。与下颌切牙一样，上颌切牙牙源性器官的这一部分由球根状部分和“U”形部分组成。然而，与下颌切牙相比，球根状部分明显更钝，“U”形部分的周长更大。尽管在上颌切牙和下颌切牙的牙源性器官各部分的细胞内容物和基本组织方面未发现差异，但在上颌切牙的球根状部分发现了特定差异。外釉上皮与星网状层之间的边界更明确，细胞流与星网状层的关系更密切，并且作为细胞流一部分的细胞明显缺乏漩涡现象。这些特征表明，上颌切牙球根状部分内部的活动比下颌切牙中的活动强度小。此外，还描述了上颌切牙牙源性器官的球根状部分、“U”形部分和根鞘部分与釉器之间的关系。
