臨床上可能因去除下顎阻生第三大臼齒手術，而造成第二大臼齒遠心側骨內缺損和牙周囊袋的形成，尤其是在25歲以上的患者。而引導組織再生術(GTR)合併脫鈣冷凍乾燥異質移植骨(DFDBA)應用於重建失去的牙周組織有超過二十年的歷史，而且有令人滿意的結果。本病例報告的目的是觀察用引導組織再生術(GTR)合併脫鈣冷凍乾燥異質移植骨(DFDBA)於治療第二大臼齒遠心側骨內缺損的長期臨床治療效果。一位36歲女性患者，自述曾在31歲時拔除上顎兩側第三大臼齒及下顎兩側阻生第三大臼齒，由診所轉介來治療局部牙齦發炎。經過第一階段牙周基本治療之後，在下顎兩側第二大臼齒遠心側，仍有7毫米的囊袋深度，因此使用引導組織再生術(GTR)以可吸收再生膜合併脫鈣冷凍乾燥異質移植骨(DFDBA)來治療。術後12個月的臨床觀察，在囊袋深度的減少和放射線X光片檢查的新骨形成，有令人滿意的結果。在往後十年的回診追蹤檢查及觀察，牙周狀況大致維持在穩定的狀態。

Impacted lower third molar surgery may cause periodontal complications on the distal surface of the adjacent second molar, such as formation of deep probing pocket depth and intrabony defects, more often to the patients group age over 25. Guided tissue regeneration (GTR) technique combined with DFDBA implantation has been applied in the field of restoring lost periodontal tissues for more than two decades with satisfactory results. The objective of this case report is to observe the long-term clinical results of combining GTR technique with DFDBA to treat the intrabony defect on the distal surface of the mandibular second molar. A 36 years old female patient who claimed her bilateral upper third molars and lower impacted third molars were extracted in age 31, was referred to our hospital to treat localized gingival inflammation. After routine periodontal phase 1 therapy, deep probing pocket depth (7mm) on distal surface of the bilateral mandibular second molar was treated by GTR procedures using bioresorbable membrane combined with DFDBA. At the 12 months postoperatively, clinical observations showed satisfactory results in reduction of probing pocket depth and radiographic bone fill. Moreover, stable clinical periodontal status had been observed during the 10 years follow-up period.