应用骨探测法探察牙槽骨嵴顶的位置，确定其生物学宽度。
We located the alveolar bone crest by sounding and determined its biological width.
结论：结果表明，只有保持正常的生物学宽度才能达到完美的效果和长久的疗效。
Conclusion: the nice effectiveness and the better curative effect depend on keeping biological width normal.
方法：对38颗牙体缺损达龈下的患牙行牙冠延长术，以恢复患牙的生物学宽度。
Methods:On 38 teeth due to various crown damages or vertical fractures in subgingival lesions were performed with surgical crown lengthening in order to achieve biologic width.
方法：对38颗牙体缺损达龈下的患牙行牙冠延长术，以恢复患牙的生物学宽度。
Methods:On 38 teeth due to various crown damages or vertical fractures in subgingival lesions were performed with surgical crown lengthening in order to achieve biologic width.
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