Journal Article β-三リン酸カルシウムナノ粒子配合コラーゲンスキャフォールドのイヌ抜歯窩骨形成促進効果

加藤, 昭人  ,  宮治, 裕史  ,  小川, 幸佑  ,  百瀬, 赳人  ,  西田, 絵利香  ,  村上, 秀輔  ,  吉田, 崇  ,  田中, 佐織  ,  菅谷, 勉  ,  川浪, 雅光

59 ( 4 )  , pp.351 - 358 , 2016-08-31 , 日本歯科保存学会
目的:β-三リン酸カルシウム(β-TCP)は骨補塡材として臨床応用されている が,吸収が遅いため組織置換に時間を要することや,残留材料の汚染による不 良な治癒発現の問題がある.そこでわれわれはナノ化技術を応用し,ナノサイ ズ化したβ-TCP 粒子をコラーゲンスポンジに配合したβ-TCP ナノ粒子配合コラ ーゲンスキャフォールドを創製した.このスキャフォールドをラット頭蓋骨に 応用した研究では,骨増生効果が認められ,またコラーゲンスポンジよりもす みやかに吸収されることが報告された.そこで本研究では,β-TCP ナノ粒子配 合コラーゲンスキャフォールドをイヌ抜歯窩へ埋植して骨形成効果を評価した. 材料と方法:β-TCP 粒子(平均粒径2.3μm)をナノ粒子に粉砕後,コール酸ナ トリウムを分散剤として,β-TCP の水分散液を作製した.次にコラーゲンスポ ンジを分散液に浸漬した後,洗浄乾燥してβ-TCP スキャフォールドを作製した. ナノ粒子の付着状態を観察するために,スキャフォールド表面のSEM 観察を行 った.イヌ抜歯窩埋植試験はビーグル犬の上顎第一前臼歯抜歯窩に,実験群で はβ-TCP ナノ粒子配合コラーゲンスキャフォールド,対照群ではコラーゲンス ポンジの埋植を行い,経時的なエックス線写真撮影による評価,ならびに2,5 週後における組織学的評価を行った. 結果:SEM 観察においてコラーゲンスポンジ線維表面に100nm 程度のβ-TCP ナノ粒子が認められ,スポンジ内部は粒子で埋まることなく維持されていた. 抜歯窩埋植試験の結果,実験群のエックス線写真では対照群と比較して不透過 - 3 - 性の亢進が早期に認められた.組織学的観察では,2 週の実験群で抜歯窩内に既 存骨から連続する新生骨が多く認められ,スキャフォールド内部に多量の細胞 や血管を観察した.一方,2 週対照群の新生骨はわずかであった.5 週の実験群 では抜歯窩内に残存スキャフォールドは認められず,中心部まで新生骨を認め た.対照群5 週では新生骨が観察されたが,一部の標本では抜歯窩中心部が結 合組織と残存コラーゲンスポンジで占められていた.2 週における新生骨形成率 は,実験群が対照群に比べて約3 倍以上と有意に大きく,埋植材残存率は,実 験群が有意に小さかった. 結論:β-TCP ナノ粒子配合コラーゲンスキャフォールドは良好な生体親和性, 吸収性を示し,イヌ抜歯窩の骨形成を促進した.
Purpose: Beta-tricalcium phosphate (β-TCP) exhibits biocompatibility and osteoconductivity and has been used clinically as a bone graft material. However, conventional β-TCP degrades slowly, with residual material frequently inducing aberrant healing. We therefore developed a collagen scaffold containing β-TCP nanoparticles by applying nanoscale dispersing technology. When the nano-β- TCP/collagen scaffold was implanted into rat cranial bone, its degradation and bone augmentation were remarkable when compared with collagen sponge. Accordingly, we evaluated the bone-forming effects of nano-β-TCP/collagen scaffold on extraction sockets in dogs. Methods: β-TCP powder (average particle size: 2.3 μm) was pulverized into nanoscale particles and dispersed into distilled water along with the surfactant sodium cholate (0.2 wt%). Collagen sponge was immersed in a dispersion (1 wt%) of β-TCP nanoparticles. This was followed by rinsing and freeze-drying to yield the nano-β-TCP/collagen scaffold. The surface of the scaffold was characterized by SEM. Subsequently, the extraction socket of a maxillary first premolar was filled with nano-β-TCP/collagen scaffold in the experimental group, while collagen sponge was applied to the socket in the control group. Radiographic images of the socket were then obtained at baseline, and at 1, 3 and 5 weeks after surgery. Histological observations were performed at 2 and 5 weeks. - 20 - Results: SEM images showed nanosized (approx. 100 nm) β-TCP particles attached to the fibers of collagen sponge. The interconnected spaces within the collagen sponge were not filled with β-TCP particles. In the experimental group, the extraction socket showed increased radiopacity when compared with the control group. Histological observation at 2 weeks revealed that new bone was present in the socket in the experimental group. In addition, ingrowth of cells and blood vessels was detected in the nano-β-TCP/collagen scaffold. In contrast, only slight new bone growth was seen in the control group. At 5 weeks in the experimental group, the scaffold had disappeared and the extraction socket was fully filled with new bone. In the control group, although new bone was detected, connective tissue and residual collagen sponge were also observed in part of the extraction socket. Newly formed bone area in the experimental group (25.1%) was significantly greater when compared with the control group (7.6%). Residual material area in the experimental group (59.1%) was significantly less when compared with the control group (81.2%). Conclusion: Nano-β-TCP/collagen scaffold exhibited high biocompatibility and degradability. New bone formation in tooth extraction sockets of dogs was facilitated by implantation of nano-β-TCP/collagen scaffold.

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