This paper reports the root separation and tunneling therapy for the furcation treatment of mandibular second molar with narrow furcation entrance diameter.

• 本文提出有关下颚第二大臼齿根叉齿槽骨病变合并根叉入口径狭窄的牙齿分割合并牙冠隧道穿通术的牙周补缀治疗。