NOVEL THERAPEUTICS TO TREAT NECROTIC TEETH: THE COMBINATORIAL EFFECT OF A 3D DRUG DELIVERY SYSTEM AND SPATIALLY DESIGNED STEM CELL NICHES

摘要/摘要： 龋齿和牙齿创伤是口腔健康的主要负担。在全球范围内，21%的儿童(6至11岁)有 他们恒牙上的龋齿。在美国，18%的学童经历过牙齿创伤。牙髓损伤 由于龋齿或创伤，会导致炎症，如果不治疗，就会导致坏死。传统型 治疗坏死性未成熟恒牙可以控制感染，但既不支持牙根 牙髓的免疫活性的发展或恢复。到目前为止，还没有临床治疗方法存在 促进根管消毒，持续引导牙髓和牙本质的生长发育 坏死牙。因此，迫切需要开发一种可预测的牙髓-牙本质再生策略。 一个无细菌的环境，最终可能导致建立新的治疗方法 未成熟的牙齿有牙髓坏死。这个应用程序的目标是开发一种新的策略来刺激 构建异种可注射胶原-纤维基质系统促进牙髓和牙本质再生 硬度和选定的生长因子(GFS)，这将首先要求达到无细菌的利基。我们的 第一个假设是，电纺丝可以用来开发无毒和抗菌有效的3D管材 用于根管消毒的药物输送构造，最初释放大量抗生素并维持其 影响了好几天。建议的结构将被评估其释放特性和细胞 体外配伍。抗菌性能将使用体外感染牙片模型和 未成熟犬牙合并根尖周病的活体模型(目标1)我们的第二个假设是牙科 牙髓干细胞在添加骨形态发生蛋白-2(BMP-2)的硬质胶原基质中的移植 或在更顺应性的基质中添加血管内皮生长因子(VEGF)，当同心时 注入消毒后的根管，会分别导致牙本质和牙髓再生。我们建议 通过评估细胞存活率、增殖能力、细胞周期和细胞周期，优化新型自组装胶原-纤维基质系统。 应用基于细胞的体外分析和一种良好的方法实现内皮和成牙本质细胞的凋亡和分化 建立活体牙片SCID小鼠模型(目的2)。最后，最优和最优的回热能力 标准化的可注射胶原-纤维基质系统将使用未成熟犬的体内模型进行评估 使用药物输送结构消毒后患根尖周病的牙齿(目标3)。此应用程序是 我们首次提出了一种细胞友好的电纺3D管状药物的临床作用，这是非常创新的 用于根管消毒的输送结构。此外，我们建议将这种疗法与一种独特的 使用可注射和高度可调的胶原纤维基质扩增牙髓干的再生策略 细胞分化，在适当的位置形成牙髓和牙本质。这项拟议的研究具有重要意义 因为它将加速建立一种可靠的再生疗法来治疗坏死性未成熟 恒牙。

Abstract/Summary: Caries and dental trauma are major oral health burdens. Globally, 21% of children (age 6 to 11 years) have caries in their permanent teeth. In the US, 18% of school children experience dental trauma. Dental pulp injury due to caries or trauma, leads to inflammation, which if left untreated, results in necrosis. Traditional therapeutics of necrotic immature permanent teeth allows for infection control, but support neither root development nor restoration of the immunocompetence of the pulp. To date, no clinical therapy exists that promotes root canal disinfection and can consistently guide the growth and development of pulp and dentin in necrotic teeth. Thus, there is a pressing need to develop a strategy for predictable pulp-dentin regeneration in a bacteria-free environment which may ultimately lead to the establishment of novel therapeutics to treat immature teeth with pulpal necrosis. The objective of this application is to develop a novel strategy to stimulate pulp and dentin regeneration by engineering an injectable collagen-fibril matrix system with heterogeneous stiffness and selected growth factors (GFs), which will first require the attainment of a bacteria-free niche. Our first hypothesis is that electrospinning can be used to develop non-toxic and antimicrobially effective 3D tubular drug delivery constructs for root canal disinfection that release initially high amount of antibiotics and sustain its effects for several days. The proposed construct will be evaluated for its release properties and cell compatibility in vitro. Antimicrobial properties will be determined using an in vitro infected tooth slice model and an in vivo model of immature dog teeth with periapical disease (Aim 1). Our second hypothesis is that dental pulp stem cell transplantation within a stiffer collagen matrix added with bone morphogenetic protein-2 (BMP-2) or within a more compliant matrix added with vascular endothelial growth factor (VEGF), when concentrically injected into a disinfected root canal, will lead to dentin and pulp regeneration, respectively. We propose to optimize the novel self-assembling collagen-fibril matrix system by evaluating the cell viability, proliferation, apoptosis and differentiation to endothelial and odontoblast cells using in vitro cell-based assays and a well- established in vivo tooth slice SCID mice model (Aim 2). Finally, the regenerative capacity of the optimal and standardized injectable collagen-fibril matrix system will be evaluated using an in vivo model of immature dog teeth with periapical disease after disinfection with the drug delivery construct (Aim 3). This application is highly innovative as we propose, for the first time, the clinical role of a cell-friendly electrospun 3D tubular drug delivery construct for root canal disinfection. Further, we propose to couple this therapy with a unique regenerative strategy using injectable and highly tunable collagen-fibril matrices to amplify dental pulp stem cell differentiation to form pulp and dentin in the appropriate locations. The proposed research is significant because it will expedite the establishment of a reliable regenerative therapeutics to treat necrotic immature permanent teeth.