Experimental Study on Recovery of Masticatory Function after Resection of the Mandible

下颌骨切除术后咀嚼功能恢复的实验研究

• 批准号: 07838047
• 负责人: IKEMURA Kunio
• 金额: $ 1.47万
• 依托单位: University of Occupational and Environmental Health
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07838047/
• 关键词: segmental mandibulectomy; reconstruction of mandible; rhBMP; fibrin glue; tricalcium phosphate (TCP); poly-L-lactide (PLLA); tray-type plate; implant

The purpose of our study was to make a masticatory function recovery after segmental mandibulectomy, using dental implants into the bone induced by applying recombinant human bone morphogenetic protein-2 (rhBMP-2) to the bone defect area. To accomplish this purpose, an appropriate carrier for expression of the rhBMP-2 activity should be investigated, and moreover it is desired to develop the plate which sustains the carrier and provides sufficient strength to reconstruct the bone defect until new bone replaces the carrier, and which is then degraded after new bone formation.1. Osteoinductive activity in rats(1) The mixture of the rhBMP-2 and its carrier, which was composed of tricalcium phosphate (TCP) and fibrin glue, was implanted subcutaneously and the osteoinductive activity was confirmed. Fibrin glue exhibited many useful benefits as an adhesion agent to other carriers rather than just as a single carrier. The TCP was unsuitable for examining new bone formation by a radiograph, be … More cause of radiopacity. The TCP prevents dental implants from planting into the newly induced mandibular bone.(2) In order to induce the new bone within eleven weeks, more than 50mug/nl of rhBMP-2 seems to be necessary.2. Development of a bioabsorbable plate for reconstructing a mandible and retaining a carrier using dogs.The bioabsorbable boly-L-lactide (PLLA) plate, which is amorphous, ca. 26x10^4 in molecular weight and one-millimeter in thickness, was evaluated.(1) The PLLA and AO plate were used on each side of the mandible, to reconstruct a one-centimeter full thickness defect.Two-point bend testing was performed immediately after mandibular reconstruction. The comparison of both plates revealed that the PLLA plates had a possible adequate fixation force.(2) Preceding the segmental resection, an impression was taken from the mandibular bone stripped of soft tissue, which was followed by making a plaster model. The PLLA plate was heated between 70-75ﾟC and, then, this plate was pressed to the plaster model. This method allows accurate reproduction of the mandibular bone and a tray-type plate.(3) PLLA plates were removed three months after mandibular reconstruction. They showed absorption here and there, and three-point bend testing revealed that the mean value of bending strength was 62% in non-used plates.This PLLA plate fulfillls the requisite for reconstructing a mandible and retaining a carrier, when the new bone can be adequately formed within three months. Less

我们的研究目的是利用重组人骨形态发生蛋白-2 （rhBMP-2）在骨缺损区诱导种植牙，使下颌骨节段性切除术后咀嚼功能恢复。为了达到这一目的，需要研究合适的载体来表达rhBMP-2活性，并且希望开发出支撑载体并提供足够强度的钢板来重建骨缺损，直到新骨取代载体，然后在新骨形成后降解。(1)将rhBMP-2及其载体由磷酸三钙（TCP）和纤维蛋白胶组成的混合物皮下植入，证实其具有骨诱导活性。纤维蛋白胶表现出许多有用的好处，作为一种粘附剂的其他载体，而不仅仅是作为单一的载体。TCP不适合通过x线片检查新骨形成，这是导致射线不透明的更多原因。TCP防止牙种植体植入新诱导的下颌骨。(2)为了在11周内诱导新骨形成，rhBMP-2的用量似乎需要超过50mug/nl。用犬重建下颌骨并保留载体的生物可吸收板的研制。生物可吸收聚l -丙交酯（PLLA）板，它是无定形的，分子量约为26 × 10^4，厚度为1毫米，进行了评估。(1)下颌骨两侧分别使用PLLA和AO钢板，重建1厘米全厚缺损。下颌重建后立即进行两点弯曲试验。两种钢板的比较显示PLLA钢板可能具有足够的固定力。(2)在节段性切除之前，先从下颌骨上取去软组织印模，然后制作石膏模型。将PLLA板加热到70-75℃之间，然后将该板压在石膏模型上。这种方法可以精确地复制下颌骨和托盘式钢板。(3)下颌骨重建后3个月取出PLLA钢板。它们到处都有吸收，三点弯曲测试显示，未使用的板的弯曲强度平均值为62%。当新骨可以在三个月内充分形成时，该PLLA钢板满足重建下颌骨和保留载体的要求。少