Photodynamic Therapy for Endodontic Disinfection

描述（由申请人提供）：由于根管系统的复杂性，根管内残留细菌的增殖导致根管失败，单靠器械和冲洗几乎不可能完全清创。我们的长期目标是发展光动力疗法（PDT）作为一种辅助技术，以消除次氯酸钠（NaOCI）器械和冲洗后残留的根管细菌。本研究要验证的具体假设是，在光活性药物致敏后，可见光可以实现对残留根管微生物的快速和完全杀灭。具体目标是：1。在拔牙的根管系统表面和牙本质小管中，利用常见的根管失效和/或感染中常见的微生物形成单一和多物种生物膜。我们将(i)通过扫描电子显微镜和共聚焦扫描激光显微镜来表征这些生物膜，我们将（ii）使用棋盘DNA-DNA杂交、聚合酶链反应（PCR）检测和培养来分析它们。2. 探讨光对根管生物膜的体外破坏。我们将(i)建立光和光敏剂的参数，以完全消除根管微生物生物膜，（ii）评估细菌杀灭，（iii）评估生物膜内细胞杀灭的分布。3. 评估光动力疗法的安全性。我们将（i)确定治疗后人类牙周韧带和骨细胞的活力，（ii）确定在不影响宿主细胞活力的情况下灭活微生物的治疗窗口，以及iii）研究细胞凋亡的诱导。4. 评价光动力疗法在人牙体内的抗菌效果。我们将使用刚拔出的受感染的人牙，评估光动力治疗对NaOCI完全预备和冲洗后根管系统残留细菌的影响。与公共卫生相关：在美国，每年因残留微生物进行的根管再治疗超过200万例。光动力疗法可能是一种辅助方法，用于杀死残留的根管细菌，这些细菌在使用光活性药物致敏后，随后暴露于光下。

DESCRIPTION (provided by applicant): 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 and 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 re-treatments 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.