患儿男,6岁,2012年9月17日因上颌乳中切牙龋损且松动到北京市门头沟区医院口腔科就诊。专科检查:61龈缘以上牙冠缺失,断面平齐牙龈,龋损呈墨浸状,探腐质软,无疼痛,叩击痛(-),冷刺激痛(-),松动Ⅱ度,牙龈无明显异常。牙齿X线片及曲面断层片(图1)显示:61牙根中度吸收,21牙冠 Children male, 6 years old, September 17, 2012 due to maxillary deciduous caries in the caries and loose to the Mentougou District Hospital of Stomatology clinic. Specialist examination: 61 above the gingival margin of the crown, the alignment of the gums, caries lesions were ink-immersed, the probe soft, no pain, percussion pain (-), cold stimulation of pain No obvious abnormalities. Tooth radiographs and surface tomographs (Fig. 1) show: Moderate tooth root absorption, 21 crowns