Abstract: As the main focus during smiling，any defect of teeth and gingiva in the maxillary esthetic zone may compromise the smile esthetics. The gummy smile，which means smiling with excessive gingiva displayed，is often seen in patients with a high smile line and altered passive eruption. By excising and shaping the periodontal soft and hard tissues，esthetic crown lengthening can effectively establish the position of gingival margin. The increased clinical crown height after surgery can also improve the white esthetics related to crown width-to-length ratio. This article illustrates a case of gummy smile accompanied with diastema in maxillary central incisors which received esthetic crown lengthening and composite resin restorations，including esthetic analysis，treatment planning，clinical implementation process and follow-up observation. This case provides evidence and clinical experience for the management of such patients.

Key words: maxillary anterior teeth, crown lengthening, diastema, resin, direct restoration

摘要： 上颌前牙美学区作为微笑过程关注的重点，区域内任何粉白美学的缺陷都可能损害整体的微笑美学，对于高位笑线伴有被动萌出不足的患者，微笑时显露牙龈过多是常见的美学问题之一。而美学区牙冠延长术通过对牙周软硬组织的切除和成形，可有效重建协调、美观的龈缘位置和曲线，增加被动萌出不足的临床冠高度，同时改善牙冠宽长比等相关白色美学缺陷。文章完整展示了1例针对因被动萌出不足所致露龈笑且存在上中切牙牙间隙的美学治疗过程，包括美学分析、治疗计划的制定、临床实施过程和随访效果观察，详细介绍了美学区牙冠延长术的手术过程，并采用美学树脂直接修复关闭窄牙间隙，为此类患者的临床诊治积累经验。

关键词: 上前牙, 牙冠延长术, 牙间隙, 树脂, 直接修复