The effect of inorganic trace elements on dentin apatite

我们的牙齿是由硬组织组成的，包括牙釉质和牙本质。牙本质是牙釉质外层下面的部分，负责牙齿的机械强度。牙本质主要由一种叫做羟基磷灰石的化合物组成，它由钙、磷酸盐和氢氧化物离子组成。在特定条件下，羟基磷灰石中的钙离子可以被其他类似大小的离子取代。这些取代可能会影响羟基磷灰石的力学和结构特性，从而影响牙本质。虽然类似的研究已经在牙釉质和骨骼等材料上进行过，但这项研究的重点是牙本质，到目前为止还没有得到太多的关注。本研究的目的是研究牙本质羟基磷灰石在不同离子溶液存在下的表现，以及它们是否能改善其性能。本研究将采用探索羟基磷灰石各种结构和力学性能的方法。结合他们的研究成果，首席研究员提出了一项教育倡议，包括为本科生开发牙科材料课程，并为高中生组织讲习班和研讨会。这项基础研究可能会产生深远而广泛的影响，因为它最终可能导致新的干预措施，以改善牙本质的强度，特别是由于糖尿病、类风湿关节炎、心血管疾病和多发性硬化症等疾病可能导致硬组织受损。技术摘要：本项目旨在通过对不同教育水平学生的多元教育和推广活动，研究无机微量矿物质（IoTM）对牙本质羟基磷灰石（HAp）结构和力学性能的影响。本项目旨在研究IoTM，特别是Mn、Cu和Li对牙本质结构和力学性能的影响，这是牙齿的重要组成部分。通过采用多学科方法，结合材料科学，生物学和生物化学，该团队寻求扩大对微量矿物质如何影响牙本质材料特性的理解。本研究的研究目的是回答以下问题：(1)IoTM（在牙本质中测量，无论是自然发生还是通过外在/内在暴露）如何影响牙本质结构，进而影响其力学性能？(2)是什么结构性质驱动了力学变化，这些变化如何根据IoTM类型（Mn、Cu或Li）和暴露时间而变化？这些目标将通过先进的成像和光谱技术来实现，包括x射线衍射、短/广角x射线散射、电感耦合等离子体质谱和扫描电子显微镜来研究IoTM在HAp中的取代、晶体性质和晶格性质。还将测试机械性能，包括塑料参数和溶解度，以确定使用人体模型的IoTM暴露。除了科学研究外，该项目还包含重要的教育目标。它旨在促进牙科材料科学的跨学科研究，培养本科生对STEM领域的兴趣，并为STEM中代表性不足的少数民族和女性提供机会。这项研究的结果可以促进改进技术和生物材料的发展，从而为影响微量矿物质调节的个体提供更好的牙科治疗。同时，它将为矿化组织领域的科学知识做出贡献，并促进STEM教育计划。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Non-technical Abstract:Our teeth are made of hard tissues, including enamel and dentin. Dentin is the part under the outer layer of enamel and is responsible for the mechanical strength of teeth. Dentin is mostly composed of a compound called hydroxyapatite, which consists of calcium, phosphate, and hydroxide ions. Under specific conditions, the calcium ions in hydroxyapatite can be substituted by other ions of similar size. These substitutions may impact hydroxyapatite's mechanical and structural properties and, consequently, dentin. While similar studies have been conducted on materials like enamel and bones, this research focuses on dentin, which has yet to receive much attention thus far. The goal of this study is to study how dentinal hydroxyapatite behaves in the presence of different ionic solutions and if they improve its properties. Methods exploring various structural and mechanical properties of hydroxyapatite will be employed in this study. In conjunction with their research efforts, the principal investigator proposes an educational initiative that involves developing a curriculum on dental materials for undergraduate students and organizing workshops and seminars for high school students. This foundational study can have far-reaching broader impacts, as it can eventually lead to new interventions that improve the strength of dentin, especially as hard tissues may be compromised due to diseases such as diabetes, rheumatoid arthritis, cardiovascular disease, and multiple sclerosis.Technical Abstract:This research project aims to investigate the influence of inorganic trace minerals (IoTM) on the structure and mechanical properties of dentinal hydroxyapatite (HAp) while engaging in multiple education and outreach activities for students at various education levels. The proposed project aims to investigate the influence of IoTM, specifically Mn, Cu, and Li, on dentin's structure and mechanical properties, a vital component of teeth. By employing a multidisciplinary approach, combining materials science, biology, and biochemistry, the team seeks to expand the understanding of how trace minerals impact dentin's material properties. The research objectives of this study are to answer the following questions: (1) How does IoTM (as measured in the dentin, either occurring naturally or through extrinsic/intrinsic exposure) affect dentin structure and, in turn, its mechanical properties? (2) What structural properties drive the mechanical changes, and how do these changes vary according to IoTM type (Mn, Cu, or Li) and exposure duration? These objectives will be accomplished via advanced imaging and spectroscopy techniques using X-Ray diffractometry, short/wide angle X-Ray scattering, inductively coupled plasma mass spectrometry, and scanning electron microscope to study the IoTM substitution in HAp, crystal properties, and lattice properties. The mechanical properties, including the plastic parameters and solubility, will also be tested to determine the IoTM exposure using human models. In addition to the scientific research, this project incorporates important educational goals. It seeks to promote interdisciplinary studies in dental material science, foster interest in STEM fields among undergraduate students, and provide opportunities for underrepresented minorities and women in STEM. The outcomes of this research can facilitate the development of improved technologies and biomaterials, leading to enhanced dental treatments for individuals with conditions impacting trace mineral regulation. Simultaneously, it will contribute to scientific knowledge in the field of mineralized tissues and promote STEM education initiatives.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.