Permalink : http://hdl.handle.net/2115/65477

KEYWORDS : α-TCP;BMP;4-META/MMA-TBB resin;bone-resin contact;4META/MMA-TBBレジン;骨-レジン接触

4-META/MMA-TBBレジンは優れた接着性と生体親和性を有し，歯根端切除術や垂直歯根破折などの接着治療に応用されている．さらに，4-META/MMA-TBBレジンは骨にも接着し，α-TCPを複合化すると硬化したレジン表面への骨の増生や新生骨基質とレジンとの接触が増加することが示唆されている．そこで，本研究では4-META/MMA-TBBレジンにα-TCPを複合化することが，レジン上への骨増生に有効であるか，さらにBMP-2で骨を誘導し，レジン上への骨増生やレジンと増生骨との接触が得られるかを検討することである． α-TCPを0wt%または60wt%で複合化したスーパーボンドのポリマー粉末１カップ，モノマー液４滴，キャタリスト１滴の割合で混和して頭蓋骨上に塗布した．さらに，rhBMP-2を含浸したコラーゲンスポンジでレジン上を被覆した群と，しない群を作製した．術後４，８週で脱灰薄切標本を作製して，レジン上部への骨形成状態を光学顕微鏡で観察し，レジンと母床骨との接触率，増生骨によるレジン被覆率，レジンと増生骨の接触率を計測した． その結果，α-TCPを複合化するとレジン上への骨増生が増加し，レジンと増生骨との接触率も向上したが，レジン上の骨増生は14.2（6.0-23.5）%（中央値，四分位範囲）と低い値であった．一方，BMPでレジン上に骨誘導するとレジン全面を骨で被覆することが可能であり，レジンと新生骨との接触率も高くなった．以上より，4-META/MMA-TBBレジンにα-TCPを複合化させ，さらにBMPでレジン表面を被覆すると，レジン全面が骨に被覆され，レジンと骨との接触率が高まることが示唆された．
It is the case that 4-META/MMA-TBB resin (Super-Bond, Sun Medical) has been used for root-end sealing following apico-ectomy and the bonding treatment of vertical root fractures because of the high adhesive property and biocompatibility. Furthermore, 4-META/MMA-TBB resin containing α-TCP was covered with augmentation of bone during the healing of a bone marrow defect and showed partially direct contact with new bone. In this study, we evaluated bone formation ratio and the direct contact ratio following BMP application on 4-META/MMA-TBB resin containing α-TCP on skulls of rats. The skin flap was elevated and periosteum was peeled out of the skull parietal bone of rats. One cup of polymer powder containing 0wt% or 60wt% α-TCP of Super-Bond was mixed with four drops of a monomer liquid and one drop of an initiator, and was applied to the bone. Two groups were prepared : one in which the resin was covered with a collagen sponge infused with rhBMP-2, and one in which it was not. Histological specimens were prepared at 4 and 8 weeks postoperation, and the sections were stained with H-E. New bone formation and histological measurements were histologically observed in bone coverage ratio over the resin and the direct contact ratio with new bone and the resin itself. As a result, bone coverage ratio and the direct contact ratio were significantly higher in the case of the resin containing α-TCP more than in case of the resin only. Bone coverage ratio in case of the resin containing α-TCP was 14.2(6.0-23.5)%. On the other hand, entire bone coverage was induced by application of BMP on the resin containing α-TCP or the resin only. The direct contact ratio in case of BMP application on the resin containing α-TCP was significantly higher than that in case of BMP application on resin only. In summary, it was suggested that the BMP application on the resin containing α-TCP, can induce bone growth covering the entire surface of the resin and increase the direct contact ratio between the resin and new bone.