Risnes S, Fosse G
Acta Anat (Basel). 1979;105(1):1-8. doi: 10.1159/000145101.
Longitudinal and transverse tooth sections of Isurus oxyrinchus were serially etched in 2.6% nitric acid. The changing optical properties of the etched surfaces were observed during the serial etchings, and the descent of the enameloid surfaces was measured. Shark enameloid seems to be less effectively etched by acid than human enamel; this difference may be due to differences in solubility between fluorapatite and hydroxyapatite. Most of the information regarding the structure of the enameloid was gained during the first five of ten etchings. The reflection of light from the surface was influenced by the orientation of the crystallites, longitudinally sectioned crystallites reflecting the light better than transversely sectioned crystallites. The dentinal extensions were continuous with and of the same structure as the underlying dentine. The radial fibers originated from the dentinal extensions, and they both contained organic material and were accompanied by crystallites. When the specimens were imbibed with water the distinctness of the dentinal extensions and radial fibers was improved.
对尖吻鲭鲨的纵向和横向牙齿切片进行了连续蚀刻，蚀刻剂为2.6%的硝酸。在连续蚀刻过程中观察蚀刻表面光学性质的变化，并测量釉质表面的下降情况。鲨鱼的釉质似乎比人类的釉质更不易被酸蚀刻；这种差异可能是由于氟磷灰石和羟基磷灰石在溶解度上的差异。关于釉质结构的大部分信息是在十次蚀刻中的前五次获得的。来自表面的光反射受微晶取向的影响，纵向切片的微晶比横向切片的微晶反射光的效果更好。牙本质延伸部分与下方的牙本质连续且结构相同。放射状纤维起源于牙本质延伸部分，它们都含有有机物质并伴有微晶。当标本吸水后，牙本质延伸部分和放射状纤维的清晰度得到了改善。
