Functional Jowbone Reconstruction Using Biodegradable Materials

本研究的目的是提出一种使用新开发的聚l -丙交酯（PLLA）网状托盘和自体颗粒松质骨和骨髓（PCBM）移植物进行颌骨功能重建的新方法。将填充新鲜PCBM的PLLA单丝、网片和网筒皮下植入22只成年犬背部，观察单丝的降解率、对网片的组织反应以及网筒内PCBM的成骨情况。对13只成年犬进行下颌骨切除术后，采用PLLA网状托盘和PCBM移植物和/或骨内种植体进行重建。丙交脂网托盘被固定在下颌骨1)凹槽表面安装下边界的下颌骨(U-fixation)(4狗),2)凹槽表面被安装上边界的下颌骨(倒U-fixation)(4狗),或3)一种稀释剂丙交脂网托盘制作 ... 更多的h植入的连接器是固定倒U-fixation和endosseous植入conneced托盘(5狗)。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%。PLLA网片植入后2个月内炎症反应轻微。3个月后，PLLA网片纤维表面出现组织细胞和多核巨细胞，随着纤维的降解，组织细胞和多核巨细胞数量逐渐增加。然而，PLLA网片周围组织几乎未见细胞浸润。PLLA网状骨柱内骨形成在植入后1个月达到高峰，骨柱内已基本被新生骨填充。4例患者临床愈合良好，术后2个月内恢复了下颌骨的连续性。术后6个月，新生骨和残余骨之间的界线在x线片上不清楚。然而，牙槽嵴的形状很差。4例倒置u型固定中有3例骨再生良好，牙槽嵴形状良好。然而，PLLA网盘有部分暴露；以上三种中有一种没有接枝吸收，其余一种有接枝吸收。5例采用较薄型PLLA网状托盘进行倒u型固定，骨再生良好，牙槽架形状良好，无托盘外露和感染。术后2个月，所有骨内种植体均稳定。结果表明，PLLA网托与PCBM结合是一种有效的颌骨重建和口腔康复技术。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