Photodynamic Therapy for Endodontic Disinfection

描述(申请人提供)：根管治疗失败是由于根管系统的复杂性导致残留在根管内的细菌的扩散，这使得仅用器械和冲洗几乎不可能完成清理。我们的长期目标是开发光动力疗法(PDT)作为一种辅助技术，以消除器械和次氯酸钠(NaOCI)冲洗后残留的根管细菌。这项研究要检验的具体假设是，可见光可以实现对光活性药物敏化后的残留根管微生物的快速完全杀灭。其具体目标是：1.开发单物种和多物种生物膜，其微生物在拔除牙齿的根管系统的根管系统的表面和牙本质小管中常见的根管失败和/或感染中很常见。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，并(Ii)使用棋盘DNA-DNA杂交、聚合酶链式反应(PCR)分析和培养来分析它们。2.研究光对根管生物膜的体外破坏作用。我们将(I)建立完全消除根管微生物生物膜的光和光敏剂的参数，(Ii)评估细菌杀灭，以及(Iii)评估细胞杀灭在生物膜中的分布。3.评价光动力疗法的安全性。我们将(I)确定治疗后人牙周膜和骨细胞的活性，(Ii)确定微生物在不影响宿主细胞活性的情况下被灭活的治疗窗口，以及iii)研究细胞凋亡的诱导。4.评价光动力疗法对人牙体外抑菌效果。我们将使用新鲜拔除的受感染的牙齿来评估光动力疗法对根管系统中残留细菌的影响，这些细菌在完成根管预备和NaOCI冲洗后。与公众健康相关：在美国，每年有超过200万例因残留微生物而进行的根管再治疗。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，这些细菌被光活性药物敏化后暴露在阳光下。

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.