Photodynamic Therapy for Endodontic Disinfection

根管治疗失败是由于残留细菌的增殖是留在根 由于根管系统的复杂性，使用器械进行完全清创 和灌溉几乎是不可能的我们的长期目标是发展光动力疗法（PDT）作为一种 根管预备后根管内残留细菌的清除 次氯酸盐（NaOCl）。这项研究要检验的具体假设是，可见光可以实现 快速和完全杀死残余根管微生物后，他们的敏化与光敏 药具体目标是： 1.用根管治疗失败中常见的微生物开发单种和多种生物膜 和/或拔出牙齿的根管系统的表面上以及牙本质小管中的感染。 我们将（i）通过扫描电子显微镜和共聚焦激光扫描来表征这些生物膜 我们将（ii）使用棋盘DNA-DNA杂交，聚合酶链 反应（PCR）测定和培养。 2.探讨根管生物膜的光破坏作用。我们将（i）建立光的参数 和光敏剂用于完全消除根管微生物生物膜，（ii）评估细菌 杀伤，和（iii）评估细胞杀伤在生物膜内的分布。 3.评估光动力疗法的安全性。我们将（i）确定人类牙周组织的活力， 韧带和骨细胞，（ii）确定微生物可以 在不影响宿主细胞活力的情况下被灭活，和iii）研究细胞凋亡的诱导。 4.评价光动力疗法对离体人牙的抗菌效果。我们将使用新鲜的 提取感染的人牙，以评估光动力疗法对牙体中残留细菌的影响。 根管治疗后根管系统的改变 与公共卫生的相关性：超过200万根管再治疗由于残留微生物， 每年在美国举行。光动力疗法可能是杀灭残根管的一种有效方法 在用光敏药物致敏并随后暴露于光之后，细菌的光致变色。

Endodontic failures are caused by the proliferation of residual bacteria that are left behind within the root canal due to the complexity of the root canal system that makes complete debridement with instrumentation and irrigation alone almost impossible. Our long-term goal is to develop photodynamic therapy (PDT) as an adjunctive technique to eliminate residual root canal bacteria after instrumentation and irrigation with sodium hypochlorite (NaOCI). The specific hypothesis to be tested by this research is that visible light can achieve a rapid and complete killing of residual root canal microorganisms after their sensitization with a photoactive drug. The specific aims are to: 1. Develop mono- and multi-species biofilms with microorganisms that are common in endodontic failures and/or infections on the surface as well as in the dentinal tubules of root canal systems of extracted teeth. We will (i) characterize these biofilms by scanning electron microscopy and confocal scanning laser microscopy and we will (ii)analyze them using checkerboard DNA-DNA hybridization, polymerase chain reaction (PCR) assays and culture. 2. Investigate the photodestruction of root canal biofilms in vitro. We will (i) establish the parameters of light and photosensitizers for the complete elimination of root canal microbial biofilms, (ii)evaluate bacterial killing, and (iii)assess the distribution of cell killing within the biofilms. 3. Assess the safety of photodynamic therapy. We will (i) determine the viability of human periodontal ligament and bone cells after treatment, (ii)determine the therapeutic window whereby microorganisms can be inactivated without affecting host cell viability, and iii) investigate the induction of apoptosis. 4. Evaluate the antimicrobial effects of photodynamic therapy in human teeth ex vivo. We will use freshly extracted infected human teeth to evaluate the effect of photodynamic therapy on residual bacteria in the root canal system after complete instrumentation and irrigation with NaOCI. Relevance to public health: More than 2 million root canal retreatments due to residual microorganisms are performed yearly in the US. Photodynamic therapy may be an adjunctive procedure to kill residual root canal bacteria after their sensitization with a photoactive drug and their subsequent exposure to light.