Abstract:

Abstract：A number of residual roots of the tooth were reserved by crown lengthening surgery. At the same time this surgery put us at the risk of medical tangle. It is a key of success to correctly select surgery indications and communicate. Clinical examination includes：the location of the margin of root，the width of keratinized gingiva，frenum position，the ratio of crown and root and furcation involvement. In order to expose residual roots of the tooth and maintain the width of keratinized gingival，the different incision design and reposition of flap must be performed.

Key words: crown lengthening surgery, biological width, bone resection, apically repositioned flap

摘要：

牙冠延长手术保留了大量的残根、残冠，但也带来了医疗纠纷的隐患。选择好手术适应证及充分的交流是手术成功的关键。临床检查包括断端的位置、角化龈的宽度、系带的附丽、冠根比、根分叉病变等情况。为了充分地暴露断端，保留角化龈的宽度，必须采取不同的手术方式。

关键词: 牙冠延长手术, 生物学宽度, 骨切除, 根向复位瓣