STUDY ON APPLICATION OF BONE MORPHOGENETIC PROTEIN/FIBROUS GLASS MEMBRANE TO DIRECT PULP CUPPING

近年来，日本进入高龄化社会，人们认识到咬合和咀嚼是维持和促进人类健康的基本和重要功能之一。保存牙髓可以长期维持牙齿和咬合功能。直接拔牙罐和活髓切断术是保存牙髓的治疗方法。传统上，氢氧化钙被用于直接拔牙罐和活髓截断术。但是，由于氢氧化钙的强烈刺激而引起的副作用是令人担忧的。骨形态发生蛋白存在于硬组织中，是诱导软骨或骨形成的生长和分化因子之一。由于BMP具有很强的生物活性，临床应用前景广阔。本研究对BMP诱导牙本质二次形成进行了基础研究。首先，在动物实验中，我们发现玻璃纤维膜是骨形态发生蛋白的良好载体。接下来，我们发现磷酸根在牙本质的形成中起着重要的作用，而磷酸基团是矿物质诱导所必需的。然而，在牙本质脱矿过程中，磷酸基和羧基的协同作用对牙本质基质中矿物质的诱导非常重要。此外，牙本质胶原蛋白的稳定增加了磷酸盐在牙本质中诱导矿化的能力。

Recently, we have advanced age society in Japan, and people recognize that occlusion and mastication are one of fundamental and important function to maintain and promote human health. Conserving dental pulp leads to maintain of tooth and function of occlusion for a long time. Direct pulp cupping and vital pulp amputation have been applied as pulp conservation therapy. Conventionally calcium hydroxide has been used for direct pulp cupping and vital pulp amputation. But, side effect caused by strong stimulation of calcium hydroxide is feared. Therefore, development of new materials which have bio-afinity and function such as promotion of calcification is required.Bone morphogenetic protein (BMP) exists in hard tissues, and is one of growth and differentiation factors that induces cartilage or bone formation. Due to its strong bio-activity, clinical application of BMP in many fields is anticipated.In this study, I did fundamental study on BMP-induced secondary dentin formation. First, we found that fibrous glass membrane is an excellent carrier of BMP in the experiment using animals. Next, we found that phosphophoryn plays an important role in dentinogenesis, and phosphate group is essential for mineral induction. However, co-operation of phosphate group and carboxyl group is very important for mineral induction in dentin matrix when dentin is demineralized. Furthermore, stabilization of dentin collagen increases the ability of mineral induction by phosphophaoryn in dentin.