Due to the complicated anatomical structures in the furcation area of multirooted mandibular first molars, dental hygiene is greatly compromised once the furcation is involved in the periodontitis, leading to the unfavorable prognosis of teeth with furcation involvement. A patient came to a dental office with the chief complaint of "mobile mandibular posterior tooth" 27 years ago. The periapical film showed alveolar bone resorption at the root furcation of the right mandibular first molar. Flap surgery and fine supportive therapy were conducted. The patient was diagnosed with "furcation involvement Class Ⅲ" during a revisit three years ago. Satisfactory and healthy periodontal statuses were observed 2, 9, 24, and 33 months after the periodontal flap surgery plus tunneling procedures. A follow-up of 27 years in the present case demonstrated that a favorable prognosis of furcation involvement can be achieved after adequate periodontal treatment.
下颌第一磨牙根分叉处解剖结构复杂，牙周破坏累及根分叉后，清洁困难，影响其临床预后。27年前患者因“右下后牙松动”就诊，X线根尖片显示46牙根分叉处牙槽骨破坏；经翻瓣术后，定期牙周维护治疗。3年前复诊，临床诊断为Ⅲ度根分叉病变，经过翻瓣术+隧道成形术治疗后，2、9、24和33个月复查显示牙周组织健康。本病例27年的随访结果提示，根分叉病变经完善的牙周治疗可以获得良好的预后。.
Keywords: furcation involvement; mandibular first molar; tunnel preparation.