不同年龄离体牙牙釉质酸蚀后超微结构研究

Surface morphology after teeth etched in different age groups by scanning electron microscopy

目的观察不同年龄组牙釉质酸蚀后的超微结构。方法收集2012年3月至2013年3月在中国医科大学口腔医学院口腔外科拔除的牙齿24颗，分为乳牙组（9～12岁）、年轻恒牙组（10～14岁）、青年恒牙组（25～40岁）、老年恒牙组（60岁以上）。用酸蚀剂处理不同年龄组牙齿的颊侧牙釉质表面，各实验样本分别冲洗、固定、脱水、干燥、喷金，应用扫描电镜观察各组被处理表面的超微结构形态。结果乳牙组釉质表面较粗糙，釉柱排列形态不规则．相同的酸蚀时间乳牙组的牙釉质脱矿比恒牙明显。年轻恒牙组可见明显的釉柱端凹陷，釉柱表层排列松散；青年恒牙组牙釉质表面排列规整、致密，未见釉柱端凹陷；老年恒牙组牙釉质成不规则的点隙、裂沟，原有的釉质结构部分消失，蜂窝状结构明显。结论不同年龄组牙釉质抗酸能力及脱矿形式不同。

Objective To observe enamel surface morphology of different age groups after teeth etched, so as to guide the further clinical application and provide theoretical basis for treatment. Methods According to age standard, collect samples and divide them into four groups：the deciduous teeth group （9 to 12 years old）, the young permanent teeth group （ 10 to 14 years old）, the youth permanent teeth group（25 to 40 years old）, the old age permanent teeth group（more than 60 years old）. Acid etches were used to etch the surfaces of the buccal enamel. Every experiment sample was flushed, fixed, dehydrated, dried and metal sprayed. And the surfaces of ultra-microstructures were observed by scanning elec- tron microscopy（SEM）. Results The enamel surface was rough in the deciduous teeth group;the arrangement of enamel rods were irregularlar. The depressed enamel rods were obviously seen in the young permanent teeth group, the surface of enamel rods were lined up neatly in the youth permanent teeth group, and the depressed enamle rods were not seen. In the old age permanent teeth group the pit and fissure of enamel and the original enamel structure disappeared, and the honeycomb structure were obviously seen. Conclusion The acid resistance and the demineralization of tooth enamel are different in different age groups.