中国实用口腔科杂志

中国实用口腔科杂志

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不同参数Er∶YAG激光照射对早期脱矿釉质表面形貌及微区成分影响的实验研究

徐晓雅，徐冬雪，黄文燕，黄毅鹏   

  1. 广州医科大学附属口腔医院·广州口腔疾病研究所·口腔医学重点实验室，广州  510140
  • 出版日期:2019-11-15 发布日期:2020-03-12
  • 基金资助:
    广东省医学科研基金（A2018373）

  • Online:2019-11-15 Published:2020-03-12

摘要： 目的    比较不同参数Er∶YAG激光照射对早期脱矿釉质表面及微区成分的影响，探索早期脱矿釉质防龋的适宜能量密度。方法    将50颗拔除的新鲜前磨牙切割成6 mm × 5 mm × 2 mm大小的釉质块，于每个釉质块唇面建立直径1 mm的开窗区，在脱矿液中浸泡3 d，制备早期釉质龋模型。将标本随机均分为5组，对照组不进行激光照射，实验1组、2组、3组、4组分别用40、50、60、70 mJ的Er∶YAG激光照射脱矿釉质表面5 s。应用扫描电镜及能谱分析仪进行釉质表面形貌观察及成分分析。采用单因素方差分析和SNK-q检验比较各组间的差异。结果    与对照组相比，各实验组均产生釉质表面形态学的改变，实验3组和4组釉质表面消融明显。能谱分析结果显示，激光照射后各实验组釉质中C元素质量分数下降，实验1、2和3组的Ca元素质量分数、实验1组和2组的P元素质量分数以及实验2组和3组的Ca、P元素质量分数比值（Ca/P比值）均升高，差异有统计学意义（P < 0.05），但实验3组的Ca/P比值升高可能与P元素质量分数降低有关。结论    50 mJ的Er∶YAG激光照射早期脱矿釉质表面未造成牙釉质表面实质性缺损，改变了釉质组织化学结构，增加了早期脱矿釉质的耐酸性。

关键词: 早期脱矿釉质, Er∶YAG激光, 扫描电镜, 能谱分析

Abstract: Objective　To evaluate morphological and chemical changes on early demineralized enamel produced by Er∶YAG laser irradiation with different energy densities in vitro，and to explore proper irradiation densities in caries prevention. Methods　Fifty freshly extracted premolar teeth were used in this study. All the teeth were cut into 6 mm × 5 mm × 2 mm enamel blocks. A 1 mm-diameter lesion window was established on the lip surface of each sample and all the samples were immersed in the demineralized solution for 3 d. The windows were randomly divided into 5 groups：Control，G1，G2，G3 and G4. Er∶YAG laser irradiation at 40 mJ，50 mJ，60 mJ and 70 mJ was performed respectively at a pulse duration of 5 s for G1，G2，G3 and G4. Scanning electron microscope（SEM）and energy spectrum analyzer were used to observe the surface morphology and to analyze the composition of enamel. One way analysis of varianceand the Test of SNK-q were used for difference comparison among groups. Results    Compared with control group，the morphological changes of the enamel surface were observed in all the lased groups，G3 and G4 showed more exposed prisms，fractures，and melting surfaces. The results of energy spectrometry analysis showed that C atomic percentage（at %）decreased in all the lased groups；Ca at % increased in G1，G2 and G3；there were increments in P at % in G1 and G2；Ca/P increased in G2 and G3，but in G3，the increase in Ca/P might be related to the decrease of P at %. Conclusion    Early demineralized enamel is not ablated or melted by 50 mJ Er∶YAG laser. Structural and chemical changes and increased acid resistance of early demineralized enamel were observed.

Key words: early demineralized enamel；Er∶YAG laser；scanning electron microscopy, SEM；energy spectrometry analysis