A case of immediate tooth transplantation after residual cyst extirpation.

今回我々は，受容部に認めた残留嚢胞の摘出と同時に軽度の歯周炎を有する歯を移植し，良好に経過した症例を経験したので報告するとともに，その成功要因について移植歯と受容部の予後因子について検討した。症例は53歳，女性。移植歯は上顎左側智歯で，歯周ポケット4mm，付着の喪失4mm で軽度の歯周炎を呈していた。受容部は下顎右側第一大臼歯相当部歯槽堤で，パノラマおよびデンタルＸ線写真で歯槽頂のやや下方に境界明瞭で類円形のＸ線透過像が認められた。移植歯は3根でやや肥大していたが，歯根膜の付着量は口蓋根で11mm，頬側根で8mmであった。嚢胞の摘出に際しては，同部が移植窩となることを考慮して病変にアプローチしたところ，歯槽頂より7～8mm下方に嚢胞を認め摘出した。そのため移植窩はその下方で嚢胞摘出腔と連続したが，歯槽頂から7～8mmの高さでは4壁の歯槽骨が確保でき，移植歯と移植窩の適合は良好であった。術後3週目で固定を除去し，根管治療を開始した。術後3か月目に根管充填を行い，移植後8か月で最終補綴治療を行ったところ，デンタルＸ線写真でも移植歯周囲の骨新生は良好であった。現在，術後6年を経過しているが経過は良好である。この理由として，移植窩形成時に移植窩上縁に4壁の歯槽骨が確保でき，移植歯の歯頸部付近での適合が良好であったこと，移植歯の歯根膜付着が確保できたことなどが考えられた。The purposes of this article were to report a successful case of immediate autotransplantation after surgical extirpation of a residual cyst, and to review donor tooth- and recipient site-associated factors that favored the outcome. The case is of a 53 years old female. The donor tooth was the maxillary left third molar that developed mild periodontitis with probing pocket depth of 4 mm and attachment loss of 4 mm. In panoramic and dental x-rays, the lesion appeared at the alveolar crest slightly downward in the mandibular right first molar region as a well-demarcated unilocular radiolucency. The donor tooth had three slightly hypertrophic roots, but with enough attached periodontium on root surfaces. As a result of surgical extirpation of the cyst observed at 7-8mm depth below the alveolar ridge, the bottom of the transplant socket became continuous with the extirpation defect. However, we were able to preserve the buccal and lingual walls of the alveolar bone, and successfully prepared a 7-8-mm-deep, 4-wall transplant socket that conformed well to the transplanted tooth. We removed the resin-wire splint used for fixation 3 weeks postoperatively and started endodontic treatment. We performed root canal filling with gutta-percha 3 months postoperatively and prosthetic treatment was done 8 months postoperatively. Control radiographs taken during 6 years of follow-up displayed disappearance of radiolucency, clearly visible periodontal ligament space around the transplant, and no signs of root resorption, indicating good healing. The favorable outcome of this case may be attributable to the following factors: (i) successful creation of a four-wall transplant socket; (ii) good initial stability due to good conformity of the cervix of the transplant; (iii) absence of osteosclerotic findings around the cystic radiolucency at the first molar region; and (iv) successful periodontal reattachment of the donor tooth