一、釉质

釉质（enamel）为覆盖于牙冠的高度矿化的硬组织，是全身唯一无细胞性、由上皮细胞分泌继而矿化的组织，而且其基质由单一的蛋白质构成，不含胶原，对咀嚼压力和摩擦力具有高度耐受性，是龋病最先侵及的组织。

（一）釉柱

釉柱（enamel rod）： 为釉质的基本结构，呈细长柱状，贯穿釉质全程，从釉牙本质界放射状伸向釉质表面，其行走方向反映了成釉细胞形成釉质时向后退缩的路线并非径直。在窝沟处，釉质从釉牙本质界向窝沟底部集中呈放射状；在牙颈部，釉柱几乎水平排列；釉柱直径平均 4~6μm，表面比深部大。

Enamel rod： As the basic structure of enamel, enamel rods are long columns that run through the enamel and extend radially from the EDJ（enamel dentinal junction）to the enamel surface. The walking direction reflects the non-straight backward retraction of the Ameloblasts when they form the enamel. In the pit and fissure, the enamel concentrated from the EDJ to the bottom; the enamel rods are almost horizontally arranged in the neck of the tooth. The diameter ranges from 4 to 6μm on average and the surface is larger than the deeper part.

（二）横纹

横纹（cross striations）： 为釉柱上有规律间隔的细线，横纹之间的距离约为 4μm，相当于釉基质每日形成的量。横纹处矿化程度稍低，故当牙轻度脱矿时横纹较明显。

Cross striations： Enamel rods have regularly spaced cross striations and the distance between the transverse stripes is about 4μm, which is equivalent to the amount of enamel formed daily. The degree of mineralization at the cross striations is slightly lower so they are more obvious when the teeth are slightly demineralized.

（三）绞釉

绞釉（gnarled enamel）： 釉柱自釉牙本质界至牙表面的行程并不完全呈直线，近表面l/3 较直，而内 2/3 弯曲，在切缘及牙尖处绞绕弯曲更为明显，称为绞釉。绞釉可以增强釉质对咬合力的抵抗。

Gnarled enamel： The enamal rod from the EDJ the surface is not completely straight. The upper 1/3 of surface is relatively straight while the inner 2/3 is curved. It is more obvious at the cutting edge and the tip of the tooth. It is called gnarled enamel, which can enhance the resistance of enamel to bite force.

（四）釉质生长线

釉质生长线（incremental line）： 又称芮氏线（line of Retzius），横磨片中此线呈深褐色同心环状排列，类似树的年轮。纵磨片中，生长线自釉牙本质界向外，在牙尖呈环形包绕牙尖，近牙颈部呈斜形线。釉质生长线是釉质周期性生长速率改变形成的间歇线。

Incremental line： Also known as the line of Retzius. In cross grindings the line is arranged in dark brown concentric rings, resembling the tree's annual rings .In longitudinal grindings, the growth line is outward from the EDJ. In the tip, the lines wrap around in ring shape while they incline in the neck. The incremental line is an intermittent line formed by the change in the periodic growth rate of enamel.

（五）釉梭

釉梭（enamel spindle）： 釉梭是起始于釉牙本质界伸向釉质的纺锤状结构，形成于釉质发生的早期。此时牙本质细胞的突起穿过基底膜伸向前成釉细胞之间。釉质形成时此末端膨大的突起留在釉质内。在磨片中，牙尖和切缘部位较多见。

Enamel spindle： Enamel spindle is a spindle-like structure that starts from the enamel dentin and extends to the enamel, which is formed in the early stage of enamel. At this time, the protrusion of the dentin cells passes through the basement membrane and extends between the Ameloblasts. This end-expanded protrusion remains in the enamel when the enamel is formed. In the grindings , they are more commonly seen in the cusp and the margin.

（六）釉板

釉板（enamel lamella）： 釉板是片状、贯穿整个釉质厚度的结构缺陷，在磨片中观察呈裂隙状结构。其钙化程度低、窄而细长，数量比釉丛少，在釉质横断面容易观察到。

Enamel lamella： Enamel lamella is a sheet-like structural defect that runs throughthe entire enamel thickness, starting from the enamel surface, stopping within the enamelor reaching the EDJ. Observed in the grindings, it is a crack-like structure. It is low -calcified,narrow, slender and sparser than enamel spindles. They are easier to observe in the crosssection .

（七）釉牙本质界

釉牙本质界（enamel dentinal junction, EDJ）： 代表来自于上皮和外间充质两种不同矿化组织的交界面，其外形呈连续的贝壳状而不是一条直线。这种连接增大了釉质和牙本质的接触面，有利于两种组织牢固结合。

Enamel dentinal junction： EDJ represents the interface from two differentmineralized tissues, epithelial and external mesenchyme.It shapes like a continuous shellshape rather than a straight line. This connection enlarges the contact surface between theenamel and the dentin, which facilitates the firm bonding of the two tissues.

（八）无釉柱釉质

无釉柱釉质（rodless enamel）： 在近釉牙本质界最先形成的釉质和多数乳牙及恒牙表层，有 20~100μm厚的釉质看不到釉柱结构。近釉牙本质界处的无釉柱釉质，是成釉细胞在最初分泌釉质时Tomes突尚未形成所致，而外层则是成釉细胞分泌活动停止及Tomes突退缩所致。

Rodless enamel： In the earliest-formed enamel which sits near EDJ and the surfaceof most baby teeth and permanent teeth, about 20~100μm of the enamel is not visible. Therodless enamel near the EDJ takes shape because the Tomes sag has not formed when theenamel cells first secrete enamel, while the outer layer is caused by the end of Ameloblastsecretion activity and the retraction of Tomes sag. Tumy4d48uBNtoj6G6wEA3mECYdclbtr/p0z9pL96QF6kl5ZRs4gz4OAYoqIA0B3z