CALCIUM PHOSPHATE BONE REPAIR MATERIALS

磷酸钙骨修复材料

• 批准号: 6379788
• 负责人: LAURENCE C. CHOW
• 金额: $ 19.11万
• 依托单位: AMERICAN DENTAL ASSOCIATION FOUNDATION
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-05-01 至 2004-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6379788
• 关键词: analog; bicarbonates; biomaterial development /preparation; biomaterial evaluation; biomechanics; calcium phosphate; cementum; crystallization; dental bonding material; glycerol; hardness; hydrolysis; hydroxides; hydroxyapatites; oral facial restoration material; potassium; sodium; solid state; solubility; solutions; statistics /biometry; stoichiometry; tensile strength

DESCRIPTION (Adapted from the Investigator's Abstract): A calcium phosphate cement (CPC), developed under this research project, was approved by the FDA in 1996 for cranial defects repair applications in humans, thus becoming the first material of its kind to be available for clinical use. While CPCs were shown to be very useful in a number of dental and medical applications for which other materials do not work well, in vivo study results suggest that in order to achieve the best results, CPC should have handling and in vivo properties that are best suited for the particular clinical application. The objectives of the proposed research are to elucidate mechanisms of cement setting reactions and to understand the physicochemical factors that influence cements= handling and in vivo properties. Four specific aims are proposed. Aim 1 proposes to understand factors that control the hydrolysis reactions of tetracalcium phosphate (TTCP), alpha-tricalcium phosphate (alpha-TCP), dicalcium phosphate dihydrate (DCPD), dicalcium phosphate anhydrous (DCPA) and calcium hydroxide. These calcium phosphate salts are the major components of different CPCs. Hydrolysis of one or more of the salts that form hydroxyapatite (HA) is responsible for the hardening of the cement. A better understanding of the hydrolysis reaction of each of these salts will provide important insights into factors that influence some important cement properties, including the rate of conversion to HA, formation of Ca-deficient or stoichiometric HA, the crystallinity HA, etc. Defective or non-stoichiometric HAs are believed to be more bioresorbable. Aim 2 proposes to study the dissolution rate of cement products in demineralizing solutions having ionic compositions mimicking the acidic environment produced by osteoclasts. A dual constant-composition titration system was developed during the report period for measuring dissolution rates of calcium phosphate biomaterials under simulated acidified physiological solutions. The Principal Investigator proposes to use this technique as an in vitro model for predicting resorption rates of CPC and to understand factors that control the dissolution rate. Aim 3 proposes to study properties of non-rigid and resorbable calcium phosphate cements. Experiments are described to study composites of CPC and chitosan, a biocompatible polymer to form self-hardening, bioresorbable, and non-rigid bone graft materials. These materials should be useful in a number of applications in which the implant can remain stable and firmly attached to the bone defect surface despite micro-movements of the defect walls. Aim 4 will study properties of injectable premixed calcium phosphate cement pastes. Premixed CPC pastes have the advantages that they are stable in the package and harden only after delivery to the defect site where the non-aqueous liquid is replaced by water from the surrounding tissue. While premixed CPC is considerably easier to use and is injectable, its properties are quite different from the conventional CPCs. The hardening time, resistance to washout, and HA conversion of premixed pastes consisting of CPC powder and non-aqueous liquids, such as glycerin, will be studied. The Principal Investigator also proposes to determine mechanical properties of the hardened CPC pastes.

描述（改编自研究者的摘要）：磷酸钙 根据该研究项目开发的水泥（CPC），已获得FDA的批准 1996年，用于人类中的颅缺陷修复应用，因此成为第一个 此类材料可供临床使用。当CPC被证明 在许多其他牙科和医疗应用中非常有用 材料效果不佳，体内研究结果表明，为了 达到最佳结果，CPC应该具有处理和体内特性 最适合特定的临床应用。目标的目标 拟议的研究旨在阐明水泥设定反应的机制和 了解影响cements =处理和的理化因素 体内特性。提出了四个具体目标。目标1提议 了解控制四钙的水解反应的因素 磷酸盐（TTCP），α-磷酸盐（Alpha-TCP），磷酸二钙磷酸盐 二氢酸盐（DCPD），磷酸二二硫酸二核无水（DCPA）和氢氧化钙。 这些磷酸钙盐是不同CPC的主要组成部分。 一种或多种形成羟基磷灰石（HA）的盐的水解为 负责水泥的硬化。更好地理解 每种盐的水解反应将提供重要的见解 影响某些重要水泥特性的因素，包括 转换为HA，形成CA缺陷或化学计量的HA， 据信，结晶度HA等。 更多的生物可吸收。 AIM 2建议研究水泥的溶解速率 具有离子成分的脱矿质化溶液中的产品模仿了 破骨细胞产生的酸性环境。双重恒定组合 在报告期间开发了滴定系统以测量 模拟酸化的磷酸钙生物材料的溶解速率 生理解决方案。主要调查员建议使用此 技术作为预测CPC的吸收率和TO的体外模型 了解控制溶解速率的因素。 AIM 3建议学习 非刚毛和可吸收磷酸钙水泥的性质。实验 被描述为研究CPC和壳聚糖的复合材料，这是一种生物相容性聚合物 形成自我刻痕，可生物可闻和非刚性骨移植物材料。 这些材料应该在许多应用中有用 植入物可以保持稳定并牢固地连接到骨缺损表面 尽管缺陷壁微动。 AIM 4将研究 可注射的预混合磷酸钙水泥糊。预处理CPC糊有 它们在包裹中稳定并仅在此之后变硬的优点 输送到缺水液体被水代替的缺陷部位 来自周围的组织。虽然预处理的CPC非常容易使用 并且是可注射的，其特性与常规的特性完全不同 CPCS。较固的时间，抵抗冲洗和HA转换为预混合 由CPC粉末和非水液（例如甘油）组成的糊状物将 被研究。主要研究者还建议确定机械 硬化CPC糊的特性。