In the oral and maxillofacial region, autologous grafting has been used to treat tissue defects caused by congenital anomaly, trauma or tumor resection. However, as long as autologous grafts are used, these operations must include the process of harvesting the patient’s tissues, and the amount obtained for the graft may be limited. To overcome such issues with the conventional approach, we have tried to develop tissue-engineered bone and cartilage.
We have succeeded in making custom-made artificial bone （CT-Bone） by printing alpha-tricalcium phosphate particles with a 3D printer based on DICOM data of CT images. Clinical research and trials of CT-Bone have been conducted in 30 patients with bone defects in the oral and maxillofacial region, confirming its efficacy in restoring facial features. Based on this technique, we are now developing a next-generation bio-3D printer.
To develop implant-type tissue-engineered cartilage with proper 3D morphological form and mechanical strength, we have optimized the culture medium of chondrocytes and the scaffold. Following a preclinical study, we have conducted clinical research in three patients with nasal deformity associated with cleft lip and palate, and are now starting a clinical study. We are also engaged in research on ear reconstruction using iPS cells.

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Patients with a defect of the hard palate caused by tumor resection suffer a remarkable decline in speech function due to abnormality of the resonance cavity and articulation. However, the speech function may be improved by wearing a prosthesis. The purpose of this study was to clarify how much a soft palate defect affects speech function. Thirteen patients with a soft palate defect participated in this study. Conversation intelligibility, blowing test and nasometry were performed. In patients with soft palate defects, speech intelligibility improved with wearing a prosthesis. However, some cases showed little difference between with and without a prosthesis even though the extent of deficiency was similar to that of cases whose speech improved. Individual differences were seen in the test results. The results of this study indicate that it is important to evaluate patients with extensive deficits by considering individuals’ residual function such as velopharyngeal function.

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要旨：上顎切除患者の補綴的リハビリテーションは，チームアプローチが必要である．本研究では，上顎切除患者の術後の顎顔面補綴治療上の考慮事項に関する外科医の意識を調査することを目的として，28項目のクローズエンド型で複数選択肢のアンケートを実施した．アンケートは，東京医科歯科大学（TMDU）口腔外科，および頭頸部外科に配布し，その結果70％の回答率だった．回答者の48％は口腔外科医，52％は頭頸部外科医だった．上顎切除の経験は，口腔外科医で53％，頭頸部外科医で39％だった．上顎切除後の外科的再建を進めた経験は，口腔外科医0％に比して，頭頸部外科医は17％だった．回答者の大半は，術前から術後の補綴治療を検討していた．上顎切除の前と後の補綴的リハビリテーションの検討に関しては，頭頸部外科医は，口腔外科医47％に比して22％と，小さかった．回答者の63％は患者らを顎顔面補綴専門外来に紹介し，補綴治療を行っていた．上顎切除患者の補綴的リハビリテーションは機能回復と審美回復に寄与する．よりよい術後補綴治療を提供するために，顎顔面補綴医と外科医らが術前よりコミュニケーションを密にとり，顎顔面補綴医から外科医らへの術後の補綴装置への情報提供などをさらに行う必要があることが明らかとなった．

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Mandibular bone defects resulting from tumor resection are generally treated with mandibular reconstruction plates. In our institution, the mandibular reconstruction plates are bent using a mandibular mock-up model before operation. In this study, we investigated the usefulness of 3D printers and mock-up models. Mock-up models were prepared with a 3D printer on the basis of DICOM data from computed tomographic images of the head, which were obtained preoperatively and used to assess the range of excision of the mandibular bone. On the basis of this analysis, the mandibular reconstruction plate was bent and sterilized preoperatively and fixed to the mandibular bone intraoperatively. In this study, we compared plate fixation time between preoperative bending and intraoperative bending. The range of mandibulectomy could be sufficiently assessed before surgery by using a mock-up model. The preparation and bending of the mandibular reconstruction plate before surgery allowed the plate to be applied to the bone with minor adjustment during surgery, significantly shortening the operation time as compared with intraoperative bending of the plate. Preoperative bending of mandibular reconstruction plates based on mock-up models using a 3D printer shortens the plate-fixation time.

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