Functional Jowbone Reconstruction Using Biodegradable Materials

本研究的目的是介绍一种用于颌骨功能重建的新手术，包括使用新开发的聚（L-丙交酯）（PLLA）网状托盘和自体颗粒松质骨和骨髓（PCBM）移植物。将填充有新鲜PCBM的PLLA单丝、网片和网筒皮下植入22只成年犬的背部，并评价单丝的降解速率、对网片的组织反应以及网筒内PCBM的骨形成。在13只成年狗的下颌骨切除术后，使用PLLA网状托盘和PCBM移植物和/或骨内植入物进行重建。将PLLA网片托盘固定在下颌骨上，1）滑槽的凹面与下颌骨的下缘配合（U型固定）（4只狗），2）滑槽的凹面与下颌骨的上级缘配合（倒置U型固定）（4只狗），或3）较薄类型的PLLA网片托盘， ...更多信息 将种植体连接器固定为倒U形固定，将骨内种植体连接到托盘上（5只犬）。随访时间为1个月至1年。PLLA单丝的机械强度在植入后2个月内没有变化，3个月后仍保持其初始强度的80%。植入后2个月内，PLLA补片的炎症反应轻微。3个月后，PLLA网片的细丝表面出现组织细胞和多核巨细胞，随着细丝降解，数量逐渐增加。然而，在PLLA补片周围的组织中几乎没有观察到细胞浸润。PLLA补片圆柱体内的骨形成在植入后1个月达到高峰，圆柱体几乎被新形成的骨填充。4例U形固定均获得良好的临床愈合，术后2个月内恢复了下颌骨的连续性。术后6个月，X线片显示新骨和残留骨的边界不清。然而，牙槽嵴形状不佳。4例倒置U形固定中有3例显示骨再生良好，牙槽嵴形态良好。然而，PLLA补片托盘部分暴露;上述3例中的1例无移植物吸收，其余1例有移植物吸收。5例使用较薄PLLA网状托盘的倒U形固定均显示良好的骨再生，牙槽嵴形状良好，无任何托盘暴露或感染。术后2个月，所有骨内种植体均稳定。这些结果表明，PLLA网状托盘和PCBM移植物的组合是用于颌骨重建和口腔康复的有用技术。少

The purpose of this study is to present a new procedure for functional reconstruction of jowbone that involves the use of a newly developed poly (L-lactide) (PLLA) mesh tray and autogenous particulate cancellous boneand marrow (PCBM) grafts. PLLA monofilaments, mesh sheets and mesh cylinders filled with fresh PCBM were implanted subcutaneously into the back of 22 adult dogs and evaluated with regard to the degradation rate of the monofilaments, the tssue reaction to the mesh sheets, and the bone formation of PCBM within the mesh cylinders. After mandiblectomy, reconstruction using PLLA mesh tray and PCBM grafts and/or endosseous implants were performed in 13 adult dogs. PLLA mesh tray was fixed to the mandibular bone as 1) the concave surface of the chute was fitted to the inferior border of the mandible (U-fixation) (4 dogs), 2) the concave surface of the chute was fitted to the superior border of the mandible (inverted U-fixation) (4 dogs), or 3) a thinner type of PLLA mesh tray whic … More h had the connectors for implants was fixed as inverted U-fixation and endosseous implants were conneced to the tray (5 dogs). Follow-up periods ranged from 1 month to 1 year. The mechanical strength of PLLA monofilaments did not change for 2 months after implantation, and 80% of its initial strength was retained after 3 months. The inflammatory response to PLLA mesh sheets was slight within 2 months after implantation. Histiocytes and multinucleate giant cells appeared on the surface of filaments of the PLLA mesh sheets after 3 months and gradually increased in number as the filaments were degraded. However, almost no cellular infiltration was seen in the tissue around the PLLA mesh sheets. The bone formation within PLLA mesh cylinders reached its peak 1 month after implantation and the cylinders were nearly filled with newly formed bone. All of 4 U-fixation showed good clinical healing, and the continuity of mandible was regained within 2 months postoperatively. The boundaries between the newly formed bone and the residual bone were radiographically unclear 6 months after surgery. The alveolar ridges, however, were poorly shaped. Three of 4 inverted U-fixation showed good bony regeneration with a well-shaped alveolar ride. However, there were partial exposures of the PLLA mesh tray ; without graft resorption in one of the above 3 and with graft resorption in the remaining one. All of 5 inverted U-fixation using the thinner type of PLLA mesh tray showed good bony regeneration with a well-shaped alveolar ride, and there was not any tray exposure or infection. Two months postoperatively, all of the endosseous implants were stable. These results suggest that a combination of the PLLA mesh tray and PCBM grafts is a useful technique for jowbone reconstruction and oral rehabilitation. Less